### Visit the National Academies Press online and register for...

Instant access to free PDF downloads of titles from the

Distribution, posting, or copying of this PDF is strictly prohibited without written permission of the National Academies Press. Unless otherwise indicated, all materials in this PDF are copyrighted by the National Academy of Sciences. Request reprint permission for this book

Copyright © National Academy of Sciences. All rights reserved. 10% off print titles

Custom notification of new releases in your field of interest

Special offers and discounts NATIONAL ACADEMY OF SCIENCES

NATIONAL ACADEMY OF ENGINEERING

INSTITUTE OF MEDICINE

NATIONAL RESEARCH COUNCIL This PDF is available from The National Academies Press at http://www.nap.edu/catalog.php?record_id=13027

ISBN

978-0-309-16254-8

200 pages
6 x 9 PAPERBACK (2011) 

## Preventing Transmission of Pandemic Influenza and Other Viral

Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

Elaine L. Larson and Catharyn T. Liverman, Editors; Committee on Personal Protective Equipment for Healthcare Personnel to Prevent Transmission of Pandemic Influenza and Other Viral Respiratory Infections: Current Research Issues; Institute of Medicine

## Committee on Personal Protective Equipment for

Healthcare Personnel to Prevent Transmission of

Pandemic Influenza and Ot her Viral Respiratory

Infections: Current Research Issues

Board on Health Sciences Policy

Elaine L. Larson and Catharyn T. Liverman, EditorsTHE NATIONAL ACADEMIES PRESS • 500 Fi fth Street, N.W. • Washington, DC 20001

NOTICE: The project that is the subject of this report was approved by the Governing Board of the National Resear ch Council, whose members are drawn

from the councils of the National Acad emy of Sciences, the National Academy of Engineering, and the Institute of Medicine.

This study was requested by the Nationa l Institute for Occupational Safety and

Health of the Centers for Disease Cont rol and Prevention and was supported by Contract No. 200-2005-10881 (Task Order #8) between the National Academy of Sciences and the Centers for Disease Control and Prevention. Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the organizations or agencies that provided support for this project.

International Standard Book Number-13: 978-0-309-16254-8

International Standard Book Number-10: 0-309-16254-8

Additional copies of this report are available from the National Academies Press, 500 Fifth Street, N.W., Lockbox 285, Washington, DC 20055; (800) 624- 6242 or (202) 334-3313 (in the Wash ington metropolitan area); Internet, http://www.nap.edu.

For more information about the Institute of Medicine, visit the IOM home page

at: www.iom.edu.

Copyright 2011 by the National Academy of Sciences. All rights reserved.

Printed in the United States of America

The serpent has been a symbol of long life, healing, and knowledge among almost all cultures and religions since the beginning of recorded history. The serpent adopted as a logotype by the Institute of Medicine is a relief carving from ancient Greece, now held by the Staatliche Museen in Berlin.

Suggested citation: IOM (Institute of Medicine). 2011. Preventing transmission of pandemic influenza and other viral respiratory diseases: Personal protective equipment for healthcare personnel. Update 2010. Washington, DC: The

National Academies Press.The National Academy of Sciences is a private, nonpro fit, self-perpetuating society of distinguished scholars engaged in scientific and engineering research,

dedicated to the furtherance of science and technology and to their use for the general welfare. Upon the authority of the charter granted to it by the Congress in 1863, the Academy has a mandate that requires it to advise the federal government on scientific and technical matters. Dr. Ralph J. Cicerone is president of the National Academy of Sciences.

The National Academy of Engineering was established in 1964, under the charter of the National Academy of Sciences, as a parallel organization of outstanding engineers. It is autonomous in its administration and in the selection of its members, sharing with the National Academy of Sciences the responsibility for advising the federal government. The National Academy of Engineering also sponsors engineering programs aimed at meeting national needs, encourages education and research, and recognizes the superior achievements of engineers. Dr. Charles M. Vest is president of the National Academy of Engineering.

The Institute of Medicine was established in 1970 by the National Academy of

Sciences to secure the services of em inent members of appropriate professions in the examination of policy matters pertaining to the health of the public. The Institute acts under the responsibility given to the National Academy of Sciences by its congressional charter to be an adviser to the federal government and, upon its own initiative, to identify issues of medical care, research, and education. Dr. Harvey V. Fineberg is president of the Institute of Medicine.

The National Research Council was organized by the National Academy of

Sciences in 1916 to associate the broa d community of science and technology with the Academy’s purposes of furthering knowledge and advising the federal government. Functioning in accordance with general policies determined by the Academy, the Council has beco me the principal operating agency of both the National Academy of Sciences and the National Academy of Engineering in providing services to the government, the public, and the scientific and engineering communities. The Council is administered jointly by both Academies and the Institute of Medicine. Dr. Ralph J. Cicerone and

Dr. Charles M. Vest are chair and vice chair, respectively, of the National

Research Council.

www.national-academies.orgCOMMITTEE ON PERSONAL PROTECTIVE EQUIPMENT

FOR HEALTHCARE PERSONNEL TO PREVENT

TRANSMISSION OF PANDEMIC INFLUENZA

AND OTHER VIRAL RESPIRATORY INFECTIONS:

CURRENT RESEARCH ISSUES

ELAINE L. LARSON ( Chair ), Professor of Pharmaceutical and

Therapeutic Research, Columbia University GLORIA ADDO-AYENSU, Director, Fairfax County Department of

Health ALLISON E. AIELLO, John G. Searle Assistant Professor of Public

Health, University of Michigan School of Public Health HOWARD J. COHEN, Consultant, Professor Emeritus, University of

New Haven ROBERT COHEN, Director, Pulmonary and Critical Care Medicine,

Cook County Health and Hospitals System, and Chair, Division of Pulmonary Medicine/Critical Care and Occupational Medicine, Stroger Hospital of Cook County KAREN COYNE, Research General Engineer, U.S. Army Edgewood

Chemical Biologic Center DAVID M. DEJOY, Professor, University of Georgia KEN GALL, Professor, Georgia Institute of Technology WILLIAM H. KOJOLA, Industrial Hygienist, Department of

Occupational Safety and Health, AFL–CIO

ALLISON M C GEER, Director, Infection Control, Mount Sinai

Hospital, University of Toronto PETER PALESE, Professor and Chair, Mount Sinai School of

Medicine DAVID PREZANT, Chief Medical Officer and Special Advisor to the

Fire Commissioner for Health Policy, Fire Department of the City of New York, and Professor of Medicine, Pulmonary Division, Albert Einstein College of Medicine M. E. BONNIE ROGERS, Director, North Carolina Occupational

Safety and Health Education and Research Center and Occupational Health Nursing Program, School of Pu blic Health, University of North Carolina–Chapel Hill RICHARD P. WENZEL, Professor and Former Chair, Department of

Internal Medicine, Virginia Commonwealth University

vvi Study Staff

CATHARYN T. LIVERMAN, Project Director ANDREW M. POPE, Director SARAH CODREA, Associate Program Officer (until July 2010) LARA ANDERSEN, Research Associate JUDY ESTEP, Program Associatevii 

## Reviewers

This report has been reviewed in dr aft form by individuals chosen for their diverse perspectives and technical expertise, in accordance with procedures approved by the National Research Council’s Report Review Committee. The purpose of this indepe ndent review is to provide candid

and critical comments that will assist the institution in making its published report as sound as possible and to ensure that the report meets institutional standards for objectivity, evidence, and responsiveness to thestudy charge. The review comments and draft manuscript remain confidential to protect the integrity of the deliberative process. We wish to thank the following individuals for their review of this report:

Lisa Brosseau, University of Minnesota Benjamin Cowling, University of Hong Kong Lewis R. Goldfrank, Bellevue Hospital Center and New York University Medical Center Kathleen Harriman, California Department of Public Health Sundaresan Jayaraman, Georgia Institute of Technology Mark Nicas, University of California Daniel R. Perez, University of Maryland Trish M. Perl, Johns Hopkins University School of Medicine Peg Seminario, AFL–CIO Michael Tapper, Lenox Hill Hospital, New York City David Weber, University of North Carolina–Chapel Hill Annalee Yassi, University of British Columbia

Although the reviewers listed above have provided many constructive comments and suggestions, they were not asked to endorse the con-viii REVIEWERS

clusions or recommendations, nor di d they see the final draft of the report before its release. The review of this report was overseen by Caroline Breese Hall, University of Rochester School of Medicine, and Johanna T. Dwyer, Tufts University School of Medicine. Appointed by the National Research Council and Institute of Medicine, they were responsible for making certain that an independent examination of this report was carried out in accordance w ith institutional procedures and that

all review comments were carefully considered. Responsibility for the final content of this report rests entirely with the authoring committee

and the institution.

## Contents

ACRONYMS AND ABBREVIATIONS xi

SUMMARY 1

1 INTRODUCTION 15 Scope of the Report, 15 Background and Context, 17 Healthcare Personnel and PPE, 21 Overview of Influenza and Other Viral Respiratory Diseases, 23 Defining an Integrated Approach to PPE Research, 25 References, 27

2 UNDERSTANDING THE RISK TO HEALTHCARE

PERSONNEL 29 Background and Context from the 2008 Report, 29 Update on Recent Research, 35 Summary of Progress, 57 Findings and Research Needs, 57 Recommendations, 60 References, 60

3 DESIGNING AND ENGINEERING EFFECTIVE PPE 71 Background and Context from the 2008 Report, 72 Update on Recent Research, 74 Summary of Progress, 101 Findings and Research Needs, 102 Recommendations, 104 References, 105

ixx CONTENTS

4 USING PPE: INDIVIDUAL AND ORGANIZATIONAL

ISSUES 113 Background and Context from the 2008 Report, 113 Update on Recent Research, 116 Summary of Progress, 123 Findings and Research Needs, 124 Recommendations, 127 References, 128

5 POLICY RESEARCH AND IMPLEMENTATION: HEALTHCARE SYSTEMS, STANDARDS, AND

CERTIFICATION 133 PPE Standards and Certification, 133

Lessons Learned from 2009 H1N1 Policies Relevant to PPE for Healthcare Personnel, 141 Summary of Progress, 148 Findings and Research Needs, 149 Recommendations, 150 References, 152

APPENDIXES

A Workshop Agenda 157

B Participants List 163

C Studies of the Clinical Effectiveness of Personal Protective Equipment During Outbreaks of Severe Acute Respiratory Syndrome and Respiratory Syncytial Virus 173

D Examples of Relevant Voluntary Consensus Standards 177

E Committee Biographies 179

## Acronyms and Abbreviations

AAMI Association for the Advancement of Medical

Instrumentation

B.R.E.A.T.H.E. Better Respiratory Equipment Using Advanced Technologies for Healthcare Employees

CBRN chemical, biological, radiological, and nuclear

CDC Centers for Disease Control and Prevention CFR Code of Federal Regulations

CI confidence interval

CO 2 carbon dioxide

DOL Department of Labor

FDA Food and Drug Administration FFP2 or FFP3 filtering facepiece respirator class P2 or P3

HHS Department of Health and Human Services

ICU intensive care unit

IOM Institute of Medicine

IV intravenous

MPPS most penetrating particle size

NaCl sodium chloride

NIOSH National Institute for O ccupational Safety and Health

xixii ACRONYMS AND ABBREVIATIONS

NPPTL National Personal Prot ective Technology Laboratory NVHA Northern Virginia Hospital Alliance NYC New York City

OSHA Occupational Safety and Health Administration

PAPR powered air-purifying respirator PPE personal protective equipment PPT personal protective technologies

RNA ribonucleic acid RSV respiratory syncytial virus RT-PCR real-time polymerase chain reaction

SARS severe acute respiratory syndrome SNS Strategic National Stockpile

TICD 50 tissue culture infective dose 50 TIL total inward leakage

UV ultraviolet

WHO World Health Organization

## Summary

In 2008, the Institute of Medicine (IOM) published the report Preparing for an Influenza Pandemic: Personal Protective Equipment for

Healthcare Workers . At the time of that report, the major influenzarelated concern was avian influenza (H5N1). As novel H1N1 influenza A became a reality in 2009, the ma ny unknowns about the virulence, spread, and nature of the virus rai sed to the forefront issues regarding personal protective equipment (PPE) for healthcare personnel. A majorissue was the nature of respiratory protection required because much remains to be learned about the mechanisms of influenza transmission.This report comes at a time when controversies continue on issues related to PPE for healthcare personnel, while at the same time, new horizons in PPE research and attention to PPE innovations offer promise ofimprovements in healthcare worker safety. Keeping the research momentum going is critical, because between pandemics the focus of research efforts often moves to other issues and the nation remains underprepared.

SCOPE OF THE REPORT

The 2009–2010 H1N1 experience and its accompanying unansweredresearch questions provided the impetus for the National Personal Protective Technology Laboratory (NPPTL) at the National Institute for Occupational Safety and H ealth (NIOSH) to ask the IOM to conduct a study

12 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

that would update progress on research and identify future directions regarding PPE for healthcare personnel. 1
This report is the result of a 12-month study conducted by an ad hoc IOM committee composed of experts in the fields of infectious disease, infection control, public health, occupational safety and health, pulmonary medicine, health promotion, microbiology, emergency response andpreparedness, epidemiology, nursing, community health, industrial hygiene, and materials engineering. The IOM committee was charged with identifying new research directions, certification 2 and standards-settingissues, and risk assessment issues specific to PPE for healthcare personnel to prevent transmission of pandemi c influenza and other viral respiratory infections. The committee was specifically asked to focus on the following issues:

• research needed to understand and improve the efficacy and effectiveness of PPE, particularly face masks and respirators, forpreventing transmission of pandemic influenza or other viral respiratory infections. Specific attention was sought on issues related to the research needed to de termine the type of respiratoryprotection needed for the given exposure, to determine the requirements for protective ensembles to provide an appropriatelevel of protection based on work tasks, and to improve functionality and address human factor issues such as wearability, compliance, and communications;

• necessary certification, testing, and standards development issues; and

• priorities and resources for research and certification efforts.

To accomplish its charge, the committee held three meetings and gathered information through a scientific workshop that included a public comment session, through discussions with numerous individuals in the infection control and occupational saf ety and health fields, and through a

review of the relevant literature. As mentioned above, this report builds

on the work of the IOM committee th at released the 2008 report, and

1 The committee broadly defines “healthcare personnel” to encompass all workers in direct patient care and support services who ar e employed by private and public healthcare

offices and facilities as well as those work ing in home health care and emergency medical services, including those who are self-employed.

2 The committee broadly defines “certification” to encompass the entire conformity assessment process.SUMMARY 3

throughout this report, the prior work is summarized. In large part, this

committee’s task w as to examine research conducted since the 2008 report, to assess where research stands on issues key to improving PPE for healthcare personnel exposed to infectious respiratory diseases, and tomake recommendations to address current research gaps. Many PPE issues relevant to healthcare personnel are also directly relevant to the PPE needs of workers in other occupa tions, as well as the general public.

PPE FOR HEALTHCARE PERSONNEL

The term “personal protective equipment” encompasses the specialized clothing or equipment worn by workers for protection against health and safety hazards. For healthcare personnel, PPE may include respirators, face masks, gloves, 3 eye protection, face shields, gowns, and head and shoe coverings. Integrating the various types of protective equipment to ensure that they work together as ensembles (e.g., eye protection with a respirator) is an ongoing concern. Infection prevention and control in healthcare workplaces involve, among many other measures, the use ofPPE. Infection control precautions follow a tiered approach that considers the possible routes of transmission among patients and healthcare personnel. One of the challenges for the health care field is to clearly understandthe differences between respirators and face masks as well as their appropriate uses. Respirators are specifically designed as respiratory protection. They work either by puri fying the air inhaled by the wearer through filtering materials or by inde pendently supplying breathable air. For air-purifying respirators (often the type used by healthcare personnel) the major issues are the filtration and the fit—the effectiveness of

the filter and the extent to which the respirator has a tight seal with the wearer’s face to restrict inward leakage. Face masks, including surgical masks and procedure masks, areloose-fitting coverings that are designed to protect the patient from secretions from the nose and mouth of the physician, nurse, or other healthcare professional. Face masks are not designed or certified to protect the wearer from exposure to respiratory hazards; the role of face masks as PPE requires further research.

3 Hand hygiene is another important and eff ective component of infection control of respiratory diseases, but is not wi thin the scope of this report.4 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Measures to prevent influenza tr ansmission to healthcare personnel

include all levels of hazard controls . PPE along with vaccination and antiviral medications are components of an overall infection prevention and control program that uses engineering, administrative, and work practice controls. Although all levels of this hi erarchy are important, this report is focused on opportunities to improve PPE and the correct use of PPE in healthcare settings. In discussing the issues relevant to the use of PPE by healthcare personnel, the committee identified a set of criteria as a starting point for decisions on PPE selection and use. PPE for healthcare personnel should

• effectively reduce risks of di sease or injury to healthcare personnel;

• minimize negative interactions with or effects on patients, their families, and caregivers;

• be acceptable and usable by healthcare personnel in their daily tasks, including ease of communication and comfort;

• be practical regarding issues of cost, time, and training; and

• be appropriate to the occupational risk being encountered.

Having recently been through the 2009–2010 experience with H1N1 influenza, the committee is well aware of the ongoing challenges and controversies surrounding PPE for heal thcare personnel. At this time, it is particularly important to build on that experience and take the actions needed to address the research and policy questions that will allow the healthcare community to be better pr epared for the next epidemic or pandemic. Experience has shown that relevant research on these issues wanes between pandemics, and not perm itting that to happen this time is crucial to resolving the research questions and setting evidence-based policies in place.

UPDATE ON PROGRESS: 2007 TO 2010

Transmission of Influenza and Other Viral Respiratory Diseases

Animal studies have found that the ferret and guinea pig models appear to be highly representative of hu mans in terms of their susceptibility to infection, the influenza viral stra ins that display a transmissible phenotype, and the kinetics with which transmission occurs. Experiments per-SUMMARY 5

formed in both of these animal models suggest that transmission of influenza viruses can proceed by both droplet spray and aerosol routes, which would include respirable particles. Animal studies have alsopointed to a number of environmental factors, including relative humidity and temperature, that may influence transmission. Recent studies that employed environmental monitoring of air for influenza as well as others

that examined the contamination of fomites and hands with H1N1 have provided insights on the potential for influenza virus contamination of

the healthcare environment. Nonetheles s, data on the viability of influenza and other respiratory viruses in air samples and on fomites in these settings are limited. Mathematical m odels have been de veloped to better

characterize the relative contribution of influenza transmission modes.Available, well-specified parameters for these models are limited because information is lacking on the vi ability of influenza in aerosols, salivary virus concentrations, the amount of virus in respirable and inspirable particles, and the quantity and pe rsistence of viability on various fomites in the healthcare setting. Take n together, progress has been made in understanding the modes of transmission, but the relative contribution

of the modes are still unclear. Much remains to be learned about the effectiveness of control measures to prevent transmission.

Observational and controlled studies relevant to PPE use and transmission of influenza or other viral respiratory diseases are limited because study protocols were not usually in place for 2009 H1N1 or forrecent seasonal flu periods, and studies have not provided adequate power to answer questions regarding the effectiveness of using PPE in reducing or preventing disease transmission.

Designing and Engineering Effective PPE

PPE is a critical component in the hierarchy of controls used to protect healthcare personnel from influenz a and other viral respiratory diseases. Understanding the functional issues related to the design of PPE, as well as the factors that impact use, is critical to ensuring that healthcare personnel are adequately protected and comfortable and can perform their jobs. Important advances have been made in some areas since the last report, but other areas, particularly regarding improvements in gowns, gloves, face masks, and face sh ields, need to be more fully addressed. Much research has been done regarding filtration of respirator media, but ways to improve fit, including new technologies specifically6 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

for filtering facepiece respirators, n eed more research because face sealleakage greatly exceeds filter penetration in the overall total inward leakage of respirators. The physiological impact of respirators has been studied in depth, but research in this ar ea is lacking regarding other types of PPE. Integration issues concerning PPE and medical equipment and the impact on operational performance have not been adequately studied.Effective decontamination methods that do not impact the physical characteristics of respirators have been st udied for some types of respirators, but with inconclusive results. Finally, the characteristics of a respirator that would specifically address the needs of healthcare personnel (e.g., patient–provider interaction, comfort, reduced physiological burden) have been identified. Addressing these issues is important for developing PPE for healthcare personnel that is safe, effective, and comfortable.

Using PPE: Individual and Organizational Issues

Research during the past several years reveals modest gains in understanding that self-protective behavi or in the healthcare settings involves a constellation of interacting and independent components. At a minimum, consideration should be given to the user, the device, the task, and the general work and organiza tional context. The growing acknowledgment of contextual and organizatio nal factors means that research on PPE and healthcare personnel is closi ng in on the larger body of occupational safety research, which increasingly emphasizes those factors in understanding occupational safety performance. Although there are clear gaps and deficiencies in our knowledge baseabout PPE usage in health care, existing knowledge is sufficient to recommend a four-pronged strategy fo r immediate implementation. Thefour elements are: (1) deliberate planning and preparation at the leadership and organizational levels; (2) comprehensive training, including supervisors and managers; (3) widespread and convenient availability of appropriate PPE devices; and (4) a ccountability at all levels of the organization. In essence, there should be universal acknowledgement that PPE use is an integral component of providing quality health care. As with other priorities, this asp ect of healthcare delivery needs to be carefully planned at the organizational/instituti onal level. Furthermore, managers

and frontline workers alike need to understand and accept their roles and responsibilities, and PPE use needs to be as easy and convenient as poss-SUMMARY 7

ible. PPE should be factored into all decisions involving task design, staffing, and work assignments. Input from frontline workers should beused to facilitate planning and decision making and to maximize acceptance. Environmental/engineering cont rols should be utilized wherever possible to control exposures, with PPE used as a supplement or alternative when environmental/engineering controls are not sufficient or feasible. The overall implementation of the PPE program should be monitored regularly, with the goals of continuous improvement, adoption of best practices, and accountability of both supervisor and worker.

Policy Research and Implementation

Preparations and implementation of infection control plans for 2009 H1N1 influenza brought into sharp focus the efforts by healthcare professionals, emergency planners, professional associations, healthcare facilities, policy makers, government agen cies, labor unions, and others to address PPE policies and logistics. Artic les continue to be published on the recent experience and the challenges and successes in providing face masks, respirators, and other PPE to healthcare personnel. As lessons learned during that experience continue to add to the body of knowledge, incorporating this information into research, policy, and practice efforts will be important. In the initial phases of an epidemic or pandemic— when there are many unknowns about the virus or agent—one of the challenges is to determine PPE policy and then to adapt those policies asinformation is gained on the severity, transmission, and nature of the disease, with an emphasis on communicating the changes. Standardssetting, regulatory, training, and research efforts continue to move toward improved respiratory protection, and recent work has begun to focus on the specifics of how to tailor PPE devices and PPE training to address the specific needs of healthcare personnel.

RECOMMENDATIONS: A SYSTEMS APPROACH

TO PPE RESEARCH

Providing care to ill or injured patients involves a range of potentially hazardous exposures for healthcare personnel. Current infection control precautions address this challenge by providing guidance on PPE and other precautions that varies dependi ng on the mode of transmission of8 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

the pathogen. The ultimate goal would be to have the definitive information that would match the appropriate type of PPE with the pathogen, itsmode of transmission, the infectious dose, and its risk to healthcare personnel. In many cases in industrial settings, this level of specificity is available for chemical exposures, although other industrial settings with unknown or mixed exposures continue to pose challenges. Reaching that point for protecting healthcare personnel will require concerted research

efforts. This report explores an integrated approach that addresses the full spectrum of research (from basic resear ch to policy research) and translates research findings into improvements in the standards of healthcare practice (Figure S-1). This approach ensures that basic science initiatives are fully explored while also addr essing clinical needs and testing the results in real-world settings, with th e expectation that adaptations along the way will be made and tested. Feedback loops to prior stages are alsocritically important. Such an integrated approach calls for active collaboration and discourse among scientists and clinicians who may not have had previous interactions. Throughout this report, the committee has highlighted a number of

areas in which research is needed. This research has the potential toquickly translate new understandings of disease transmission or PPE engineering into more effective PPE products. Fully implementing these research directions and realizing breakthroughs for improved safety and

health for healthcare personnel will require commitments from multiple

CONCEPT PROOF OF

PRINCIPLE STANDARD OF

PRACTICE

Basic Science

Research (Safety) Clinical and Applied

Research (Efficacy) Systems

Research (Effectiveness) Policy and Regulatory

Research (Disease Reduction

in Populations)

T2 T3 T4 T1

FIGURE S-1 An integrated system moving research into practice, depicting the

translation of research from basic scien ce research (T1) through policy and regulatory research (T4). See Chapter 1 for further discussion.SUMMARY 9

federal agencies as well as ongoing, innovative efforts by PPE designers and manufacturers. The report mak es the following recommendations to

advance research and transfer these into practice across the spectrum of research opportunities.

Across the Spectrum of Research

Recommendation: Develop Standardized Terms and Definitions The Centers for Disease Control and Prevention (CDC) and the Occupational Safety and Health Administration (OSHA), in partnership with other relevant agencies and organizations, should work to develop standardized terms, definitions, and appropriate classifications to describe transmission routes and aerodynamic diameter of pa rticles associated with respiratory disease transmission. This effort should involve a consensus from the industrial hygiene, infectious disease, and

healthcare communities.

Recommendation: Develop and Implement a Comprehensive Research Strategy to Understand Viral Respiratory Disease

Transmission The National Institutes of Health, in collaboration with other research agencies and organizations, should develop andfund a comprehensive research strategy to improve the understanding of viral respiratory disease transmission, including, but not limited to, examining the characteristics ofinfluenza transmission, animal models, human challenge studies, and intervention trials. This strategy should include

• an expedited mechanism for funding these types of

studies and

• clinical research centers of excellence for studying influenza and other respiratory virus transmission.10 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Safety to Efficacy: Basic Science Research (T1) to Clinical and Applied Research (T2)

Recommendation: Continue and Expand Research on PPE

for Healthcare Personnel NPPTL and other agencies, private-sector companies, and other organizations should continue to advance research indesigning and evaluating the effectiveness of respirator protection for healthcare personnel and expand its research efforts to improve and evaluate the effectiveness of gloves, gowns, eye protection, face shie lds, and face masks in preventing the transmission of influenza or other viral respiratory diseases. Areas of focu sed research needs include

• effectiveness in preventing fomite, droplet spray, or aerosol transmission;

• decontamination and reusability;

• comfort, fit, and usability;

• impact on task performance; and

• development of technologies specifically for healthcare personnel.

Recommendation: Examine the Effectiveness of Face Masks

and Face Shields as PPE NPPTL should investigate the effectiveness of face masks and face shields in preventing transmission of viral respiratory

diseases.

Recommendation: Improve Fit Test Methods and Evaluate

User Seal Checks NPPTL should develop novel, simpler fit test methods and evaluate the effectiveness of performing user seal checks on N95 respirators.

Efficacy to Effectiveness: Clinical and Applied Research (T2) to Systems Research (T3)

Recommendation: Explore Healthcare Safety Culture and Work OrganizationSUMMARY 11

NIOSH and other relevant agencies, such as the Agency forHealthcare Research and Quality, and professional organizations should conduct research to better understand the role of safety culture and other behavioral and organizational factors on PPE usage in heal thcare settings. These efforts

should include

• conducting human factors and ergonomics research relevant to the design and organization of healthcarework tasks to improve worker safety by reducing hazardous exposures and effectively using PPE (e.g., reduce unnecessary PPE donning and doffing),

• exploring the links between patient safety and healthcare worker safety and health that are relevant to the use of PPE, and

• identifying and evaluating strategies to mitigate organizational barriers that limit the use of PPE by healthcare personnel.

Recommendation: Identify and Disseminate Effective Leadership and Training Strategies and Other Interventions to Improve PPE UseNIOSH and other relevant agencies and professional organizations should support intervention effectiveness research toassess strategies, including innovative participatory approaches to training, for healthcare and supervisory staff at all levels to improve PPE usage and other related outcomes across the range of healthcare setti ngs. To identify best practices, efforts should be made to

• conduct observational studies of PPE use by healthcare personnel in different types of work settings;

• develop, implement, and evaluate comprehensive leadership and training strategies and interventions that go beyond simple knowledge-based training;

• design training interventions specifically for supervisory and managerial personnel in different types of healthcare settings;

• examine long-term practice change and safety culture implementation related to educational interventions;12 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

• improve use and understanding of PPE by home and community healthcare personnel;

• develop assessment tools and metrics that take abroader approach to PPE and acknowledge the interaction of worker, task, and environmental factors;

and

• be informed by a lessons-learned summit on PPE use by healthcare personne l during the 2009 H1N1 experience.

Effectiveness to Disease Reduction in Populations: Systems Research (T3) to Po licy and Regulatory Research (T4)

Recommendation: Develop and Certify Po wered Air-Purifying Respirators (PAPRs) for Healthcare PersonnelNPPTL should develop certification requirements for a lownoise, loose-fitting PAPR for healthcare personnel.

Recommendation: Move Forward on Better Fitting RespiratorsNPPTL should continue rulemaking processes for total inward leakage regulations that require respirators to meet fit

criteria. To improve consumer and purchaser information on fit capabilities, NIOSH should establish a website to disseminate fit test results for specific respirator models on an anthropometric (NIOSH) test panel, where such data exist.

Recommendation: Clarify PPE Guidelines for Outbreaks of Novel Viral Respiratory Infections NIOSH, other divisions of CDC, OSHA, and other public health agencies should develop a coordinated process to make, announce, and revise consistent guidelines regarding the use of PPE to be worn by healthcare personnel during a

verified sustained national/international outbreak of a novel viral respiratory infection. The agencies should tailor theirguidance in a timely and coordinated manner as the virulence, contagiousness, and aff ected populations are further

characterized.SUMMARY 13

Recommendation: Standards and Certification for Face Masks

and Face Shields NIOSH, OSHA, and standards- development organizations should develop the standards and certification processes needed to assess the performa nce of face masks and faceshields as PPE. The development of standards and certification processes should be guid ed by research regarding their efficacy as PPE:

• OSHA and CDC should clarify that face masks are governed by the general PPE standard (29 CFR1910.132) and not by the respiratory protection standard (29 CFR 1910.134).

• NIOSH should work with other agencies and standardssetting organizations to develop voluntary consensus standards and independent third-party testing and certification processes for fa ce shields and face maskswith specific tests for assessing prevention of transmission of viral respiratory diseases.

Recommendation: Establish PPE Regulations for Healthcare

Personnel CDC, including NIOSH, and OSHA should develop andpromulgate guidelines and regulations that are consistent regarding the use of PPE by healthcare personnel for influenza and other viral respiratory diseases:

• To assist employers in complying with the OSHA PPE standard, OSHA should specify the voluntary

consensus standards that a re required to be met for non-respirator PPE (e.g., gowns, gloves, face shields, face masks) in the event of influenza and other viral respiratory diseases.

• OSHA, with input from CDC and other agencies and organizations, should work toward promulgating an

aerosol-transmissible diseases standard that would include prevention of the transmission of influenza and other viral respiratory diseases.14 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

While the optimist can seek comfort in the fact that progress has been made in the past several years, the pragmatist must wonder aboutthe rate of progress (or lack thereof) on such a critical issue that potentially threatens the security and eco nomic well-being of the nation and

the world. The committe e hopes that this revi ew will jumpstart and strengthen improvements in PPE for he althcare personnel that could be relevant to a range of viral respiratory diseases.

## 1

Introduction

In 2008, the Institute of Medicine (IOM) published the report Preparing for an Influenza Pandemic: Personal Protective Equipment for

Healthcare Workers (IOM, 2008). When the report was released, the major influenza-related concern was avian influenza (H5N1). As novel H1N1 influenza A became a reality in 2009, the many unknowns about the virulence, spread, and nature of th e virus raised to the forefront issues regarding personal protective equipment (PPE) for healthcare personnel. One of the major issues was the nature of respiratory protection required

because much remains to be learned about the mechanisms of influenza transmission. This current report co mes at a time when controversies continue on issues related to PPE for healthcare personnel while new

horizons in PPE research and atten tion to PPE innovations offer promise for improvements in healthcare worker safety. Keeping the research momentum moving forward is critical, because between pandemics the

focus of research efforts often moves to other issues and the nation remains underprepared.

SCOPE OF THE REPORT

The 2009–2010 H1N1 experience and its accompanying unansweredresearch questions provided the impetus for the National Personal Protective Technology Laboratory (NPPTL) at the National Institute for Occupational Safety and H ealth (NIOSH) to ask the IOM to conduct a study that would update the progress on research and identify future directions regarding PPE use for healthcare personnel.

1516 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

This report is the result of a 12-month study conducted by an ad hoc IOM committee composed of experts in the fields of infectious disease, infection control, public health, occupational safety and health, pulmonary medicine, health promotion, microbiology, emergency preparednessand response, epidemiology, nursing, community health, industrial hygiene, and materials engineering. The IOM committee was charged with identifying new research directions, certification 1 and standards-settingissues, and risk assessment issues specific to PPE for healthcare personnel to prevent transmission of pandemi c influenza and other viral respiratory infections. The committee was asked to focus specifically on the following areas:

• research needed to understand and improve the efficacy and effectiveness of personal protective equipment, particularly face masks and respirators for preventing transmission of pandemic influenza or other viral respiratory infections. Specific attention was sought on issues related to the research needed to determine the type of respiratory protection needed for the given exposure,to determine the requirements for protective ensembles to provide an appropriate level of protection based on work tasks, and to improve functionality and address human factor issues, such as wearability, compliance, and communications;

• necessary certification, testing, and standards development issues; and

• priorities and resources for research and certification efforts.

To accomplish its charge, the committee held three meetings and gathered information through a scientific workshop (Appendix A) that included a public comment session, discu ssions with numerous individuals in the infection control and occupatio nal safety and health fields, and a

review of the relevant literature. As mentioned above, this report builds

on the work of the IOM committee that released the 2008 report. Throughout this report, the prior work is summarized. In large part, this

committee’s task w as to examine research conducted since the 2008 report in order to assess where research stands on issues that are key to improving PPE for healthcare personnel exposed to infectious respiratory diseases and to make recommendations to address current research gaps.

1 The committee broadly defines “certification” to encompass the entire conformity assessment process.INTRODUCTION 17

Many PPE issues relevant to healthcar e personnel are also directly relevant to the PPE needs of workers in other occupations as well as the general public. In 2009, an Institute of Medici ne committee addressed the questionof what type of PPE was needed for the 2009 H1N1 pandemic. In addition to recommending the use of respirators because respiratory protection was deemed appropriate, the report recommended increased research on “the next generation of persona l respiratory protection technologies for healthcare workers to enhance safety, comfort, and ability to perform work-related tasks” (IOM, 2009).

BACKGROUND AND CONTEXT

Readers of this report may be familiar with the 2008 report or knowledgeable about the extensive bac kground issues regarding PPE and itsuse in healthcare settings. In lieu of including extensive background materials, the committee provides an overv iew of the context for this report by addressing the following series of questions.

What Are PPE and Personal Protective Technologies?

The term “personal protective equipment” encompasses the specialized clothing or equipment worn by workers for protection against healthand safety hazards. Specific types of PPE are selected based on the occupational hazard faced in specific work tasks or sites. “Personal protective technologies” is a broader term that includes the protective equipment as well as the technical methods, processes, techniques, tools, and materials that support their development, evaluation, and use (NIOSH, 2007; OSHA, 2002). This report most often discusses the equipment used by healthcare personnel and uses the te rm “PPE,” although in some cases

the broader term is needed. For healthcare personnel, PPE may include respirators, face masks, gloves, 2 eye protection, face shields, gowns, and head and shoe coverings. Respirators provide respiratory protection; the other products are designed primarily to provide a barrier against microbes contacting theskin or mucous membrane surfaces. Integrating the various types of pro2 Hand hygiene is another important and eff ective component of infection control of respiratory diseases, but it is not within the purview of this report.18 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

tective equipment to ensure that they work together as ensembles (e.g.,eye protection with a respirator) is an ongoing concern. Infection prevention and control in healthcare workplaces involve, among many other measures, the use of PPE.

What Are the Roles of Face Masks and Respirators?

One of the challenges for the health care field is to clearly understandthe differences between respirators and face masks as well as their appropriate uses. In this report, the terminology used by the investigators or authors of the cited journal article or report is used, but in some cases, determining whether the authors’ use of the term “masks” refers to face masks, respirators, or both was impossible.Face masks, including surgical and procedure masks, are loosefitting coverings of the nose and mouth that are designed to protect the patient from secretions from the nose or mouth of the physician, nurse, or other healthcare professional. Face masks are not designed or certified to protect the wearer from exposure to respiratory hazards. Some studies have looked at the variation in filtration capabilities of face masks (Chapter 3), but the role of face m asks as PPE requires further research. Respirators are specifically designed as respiratory protection and are certified by NIOSH (42 Code of Federal Regulations [CFR] Part 84).They work either by purifying the air inhaled by the wearer through filtering materials or by independently supplying breathable air. For airpurifying respirators (often the type used by healthcare personnel), the major issues are the filtration and th e fit—the effectiveness of the filter and the extent to which the respirator has a tight seal with the wearer’s face to restrict inward leakage. A t ype of respirators, termed surgical N95 respirators, is cleared by the Food and Drug Administration (FDA) as medical devices. To be effective, respirators must fit tightly to the face. Annual fit testing for respirators is required by the OccupationalSafety and Health Administration (OSHA), and user seal checks are required with each use (29 CFR 1910.134).INTRODUCTION 19

How Does PPE Fit into the Range of Other Workplace Safety and Preventive Measures?

Efforts to promote worker safety and health traditionally follow a hierarchy of controls. Engineering and environmental measures , such asair exchanges (including non-recirculated exchanges) or negativepressure rooms that can isolate the hazard or reduce exposure, are ubiquitous measures that affect a large number of workers and patients and do not depend on individual compliance (IOM, 2008). Administrative

controls are next in the hierarchy and include the policies, standards, procedures, and practices established within an organization to limit hazardous exposures and improve worker safety (e.g., vaccination policies,cohorting or isolating patients, hand hygiene measures, provision of appropriate and effective PPE, organi zational commitment to creating and sustaining a culture of worker safety) (IOM, 2009). At the level of work practice controls , including individual practices , the healthcare employer and individual personnel are responsible for appropriate use of PPE as well as being vaccinated and adhering to work safety practices.Measures to prevent transmission of influenza or other viral respiratory diseases to healthcare personnel incl ude all levels of hazard controls. PPE, along with vaccination and antiviral medications, are components of an overall infection prevention an d control program that uses engineering, administrative, and work practice controls. Vaccination against

influenza has been found to be eff ective in preventing the illness in the recipient with overall efficacy rates over 70 percent (Fiore et al., 2009; Treanor et al., 1999). 3 Although all levels of this hierarchy are important, this report focuses on opportunities to improve PPE and the correct use of PPE in healthcare settings.

What Federal Agencies Are Involved in Healthcare Personnel PPE?

The testing, regulation, and use of PPE by healthcare personnel involve several federal departments and agencies. Responsibilities for occupational health and safety are w ithin the purview of both the Department of Health and Human Services (HHS) and the Department of

3 The Centers for Disease Control and Prevention has noted that the influenza vaccination coverage goal for healthcare personnel shoul d be 100 percent of employees who do not

have medical contraindications and that the level of vaccination cove rage among healthcare personnel can serve as a measure of a patie nt safety quality program (CDC, 2010b).20 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Labor (DOL). The Occupational Safety and Health Act of 1970 (Public Law 91-596) created two federal agencies that focus on worker safetyand health: NIOSH (in HHS) is designated with responsibilities for relevant research, training, and education; and OSHA (in DOL) is designated with responsibilities for developing and enforcing workplace safety and health regulations.NPPTL, a NIOSH laboratory, conducts and funds research on improvements in PPE and ensembles used in a variety of occupations. NPPTL also plays an integral role in standards-setting efforts relevant toPPE. Respirators used by personnel in OSHA-regulated workplaces, including healthcare workplaces, must be NIOSH certified. OSHA respirator regulations detail employer responsibilities for establishing and maintaining a comprehensive respiratory protection program, including selection, training, and fit testing requirements. For other types of PPE, OSHA specifies the voluntary consensu s standards that the equipment must meet as well as relevant selection and training requirements. NIOSH, through NPPTL, conducts an extensive array of tests to assess respirator performance characteristics and to determine if the respirator meets the certification requirements.

To be marketed in the United States as medical devices, manufacturersof respirators, face masks, and some other types of healthcare PPE are required to obtain FDA approval or cl earance by demonstrating equivalence with a similar product on the market. A number of other departments and agencies are involved in va rious aspects of healthcare PPE. In

addition to NIOSH within the Centers for Disease Control and Prevention (CDC), the National Center fo r Emerging and Zoonotic Infectious Diseases, in conjunction with the exte rnal Healthcare Infection Control Practices Advisory Committee (HICPA C), develops infection control guidance for healthcare settings (CDC, 2010c). Public health agencies at the local, state, and federal levels play an instrumental role in developing guidelines, providing training, and assisting healthcare facilities with PPE-related issues. The Department of Defense and the Department of Veterans Affairs are actively involv ed in testing and developing PPE for military and veterans’ care applicati ons. The Department of Homeland Security focuses on emergency res ponse PPE and works to coordinate and improve standards and equipment- related issues. The Environmental Protection Agency addresses PPE issues relevant to emergency responsereadiness. The Consumer Product Safety Commission has oversight responsibilities for products sold in th e commercial marketplace, includingINTRODUCTION 21

PPE. 4 Professional associations, standa rds development organizations, and other entities also play important roles in ensuring that PPE products meet performance criteria.

How Does This Report Define the Scope

of the Term “Healthcare Personnel”?

More than 14 million U.S. worker s are employed in health care (BLS, 2010). The committee broadly defines “healthcare personnel” to encompass all workers in direct patient care and support services who are employed by private and public h ealthcare offices and facilities as well as those working in home healthcare and emergency medical services,including those who are self-employed. This broad definition of healthcare personnel encompasses those working in administration, patient care, and facilities upkeep, and it includes health professional students who are receiving instruction or who are working in healthcare facilitiesas well as volunteers trained to provide systematic, regulated, and licensed healthcare services (including emergency medical responders) (IOM, 2008, 2009). All relevant work situations with the potential forinfection risk (e.g., cleaning patient rooms, delivering food) are considered part of the healthcare workfor ce. This definition is expanded from the definition used in the 2008 repor t. The committee acknowledges that,in the midst of an influenza pandemic, many people outside the traditional healthcare workforce will become caregivers, including many family members, and they may need access to PPE.

HEALTHCARE PERSONNEL AND PPE

Many work environments offer challenges for protecting personnel— the heat and smoke of firefighting, the heights of construction work on rooftops and high-rise buildings, an d worksite noise or hazardous chemicals in industrial settings—to name a few. For healthcare personnel, several aspects of the job provide challenges for designing and wearing

4 As noted in the 2008 report, PPE products th at assert protection against a specific health hazard must have FDA approval or market clearance. Other PPE products sold in the commercial marketplace do not have requirements stipul ating premarket or other testing prior to their sale to the public. For those products that asse rt NIOSH certification, NIOSH has the authority to act against mislabeled products.22 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

appropriate PPE. These issues include in teractions with patients and family members that make communication critically important, split-second

actions in some healthcare situations that can have major consequences, and challenges in exposure monitoring. Because most types of PPE work by acting as a barrier to hazardous ag ents, healthcare personnel face challenges posed by barrier materials, including having difficulties in verbal communications and interactions with patients and family members, maintaining tactile sensitivity throu gh gloves, and addressing physiological burdens.Some types of PPE are used routinely by clinicians as part of standard infection control precautions d esigned to protect both the healthcareprofessional and the patient from disease acquisition. CDC has developed a tiered approach to infection control precautions that is detailed and reviewed by HICPAC. Standard precautions 5 (first tier) are applied to the care of all patients and include the use of gloves and hand hygiene.The second tier of precautions is used in cases where patients have documented or presumed infections or conditions that could be transmitted to healthcare personnel. The details of these transmission-based precautions are specific to situations with the potential for contact, airborne, or droplet transmission of infectious agents as defined by HICPAC (Siegel et al., 2007). Care of patients with suspected respiratory infections with viral agents—such as respiratory s yncytial virus, adenovirus, parainfluenza, influenza, or human metapneumovirus—requires the use of contact and droplet precautions to protect the healthcare worker from exposure to droplet spray and contact. The guideline further notes that once adenovirus and influenza have been ruled out, droplet precautions can be discontinued (Siegel et al., 2007, p. 121).As noted in the 2008 report, opportunities abound to provide innovative approaches that could improve PPE design to better fit healthcare needs, incorporate an emphasis on wo rker safety, and integrate worker and patient safety efforts. In discussing the issues relevant to the use of PPE by healthcare personnel, the committee identified a set of criteria asa starting point for decisions on selecting and using PPE. PPE for healthcare personnel should

• effectively reduce risks of di sease or injury to healthcare personnel;

5 See Siegel et al. (2007) for details on PPE used at each level of precautions.INTRODUCTION 23

Work Task/Procedure

Environmental and Organizational Context Healthcare

Personnel Agent/Pathogen PPE Device or

Ensemble

FIGURE 1-1 The major components and factors involved in the use of personal protective equipment in health care.

• minimize negative interactions with or effects on patients and their families and caregivers;

• be acceptable and usable by healthcare personnel in their day-today tasks, including ease of communication and comfort;

• be practical regarding issues of cost, time, and training; and

• be appropriate to the occupational risk being encountered.

In developing the report, the co mmittee considered the issues relevant to the pathogen (virus), the device, and the worker while realizing it needed to keep in mind the various work tasks of healthcare personnel, the safety culture, and other organizational issues regarding where and how they work, and the broader policy and regulatory issues. Figure 1-1 is a depiction of the major components or factors involved in PPE use in

health care.

OVERVIEW OF INFLUENZA AND OTHER VIRAL

RESPIRATORY DISEASES

This report draws on the 2009–2010 experience with H1N1 influenza A. However, a brief background secti on is included here to set the context for the report and to broaden the discussion to include other viralrespiratory diseases. Although not the focus of this report, bacterial pathogens may also be transmitted via respiratory aerosols. Influenza is a serious respiratory illness caused by infection with influenza type A or type B virus. Each year, more than 200,000 U.S.24 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

hospitalizations result from seasonal influenza and its complications (Thompson et al., 2004). Estimates of the number of deaths in the United States associated annually with seasonal influenza (from 1976 to 2007) ranged from a low of about 3,300 to a high of about 49,000, with most of the excess mortality in persons 65 ye ars and older (Thompson et al.,2010). Cases of influenza peak during the winter months in each hemisphere. The influenza A virus is cate gorized by the subtypes of its major surface glycoproteins: hema gglutinin and neuraminidase. 6 The influenza virus undergoes frequent changes in antigenicity. Vaccines and antiviral medications have been developed to prevent or mitigate the disease, although major challenges remain, particularly in determining the appropriate viral strain to be included in the annual vaccine. In contrast to seasonal occurrences of influenza, global outbreaks orpandemics occur more rarely. In the twentieth century, influenza pandemics occurred in 1918, 1957, and 19 68. The highest mortality was in the 1918 pandemic, which is estimat ed to have resulted in 675,000

deaths in the United States and 50 mi llion or more deaths worldwide (Johnson and Mueller, 2002; Morens and Fauci, 2007). The 2009 H1N1

virus was first detected in Mexico in April 2009 and quickly appeared in the United States. Although the incidence was high and difficult to measure (as only a small percentage are laboratory-confirmed cases), it was milder than expected and more likely to affect people under age 65than seasonal influenza (CDC, 2010e). In the United States, CDC estimates there were between 43 and 89 million cases of H1N1 between April 2009 and April 10, 2010, with an estimate of 8,870 to 18,300 deaths related to the 2009 H1N1 (CDC, 2010e). In late April 2009, CDC began to release 25 percent of the supplies in the Strategic National Stockpile that could be needed to protect against

the influenza virus and treat influen za patients. This equated to approximately 11 million regimens of antiviral drugs and 39 million pieces of PPE, including face masks, respirators, gowns, gloves, and face shields (allocations were based on each st ate’s population) (CDC, 2010a). Other viral respiratory diseases are also a concern for the health and safety of healthcare personnel, ranging from emerging diseases, such as severe acute respiratory syndrome (SARS), to the highly prevalent and seasonal respiratory syncytial virus (RSV). In 2003, worldwide attentionfocused on an outbreak of infections caused by a previously unrecognized coronavirus that resulted in SARS. Healthcare personnel, partic6 Hemagglutinin mediates the binding of infl uenza virus to the cells. Neuraminidase is

involved in the release of virus from infected cells.INTRODUCTION 25

ularly those not using PPE and other infection control practices, wereamong the vulnerable groups (CDC, 2003). RSV infections are especially a concern in infants and older adu lts. The symptoms of RSV infectionsare similar to other respiratory diseases, including influenza, and transmission routes of RSV include direct and indirect contact, droplet spray, and aerosol routes. Each year in the United States, 75,000 to 125,000 infants are hospitalized with RSV (CDC, 2010d), and their care may involve many types of healthcare personnel. Having recently been through the 2009–2010 experience with H1N1 influenza, the committee is well aware of the ongoing challenges and controversies surrounding PPE for health care personnel. Lessons continue to be learned regarding strategi es to address why some healthcare personnel do not use preventive measures that are available and effective,particularly because preventing disease has implications for both improving the health of the workers and their patients. At this time, it is particularly important to build on the recent H1N1 experience and take the

actions needed to address the research and policy questions that will allow the healthcare community to be be tter prepared for the next epidemic or pandemic. While the optimist can seek comfort in the fact that progress has been made in the past several years, the pragmatist mustwonder about the rate of progress (or lack thereof) on such a critical issue that potentially threatens the security and economic well-being of the nation and the world. Experience has shown that relevant research on these issues wanes between pandemics. Avoiding that scenario this time is crucial to resolving the research questions and setting evidence-based policies in place.

DEFINING AN INTEGRATED APPROACH

TO PPE RESEARCH

Providing care to ill or injured patients involves a range of potentially hazardous exposures for healthcare personnel. Current infection control precautions address this challenge by providing guidance on PPE and other precautions that varies dependi ng on the mode of transmission of the pathogen. The ultimate goal would be to have definitive information that would match the appropriate type of PPE with the pathogen, itsmode of transmission, the infectious dose, and its risk to healthcare personnel. In many cases in industrial settings, this level of specificity is available for chemical exposures, although other industrial settings with26 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

unknown or mixed exposures continue to pose challenges. Reaching that point for protecting healthcare personnel will require concerted research

efforts. This report explores an integrated approach that addresses the full spectrum of research (from basic resear ch to policy research) and translates research findings into improvements in the standards of healthcare practice (Figure 1-2). This approach ensures that basic science initiatives are fully explored, while also addressing clinical needs and testing the results in real-world settings, with th e expectation that adaptations will be made and tested along the way. Feedback loops to prior stages are also critically important. Such an inte grated approach calls for active collaboration and discourse among scientis ts and clinicians who may not have had previous interactions. Chapters 2 to 5 each begin with a short summary of the relevant discussion of the 2008 report, followed by an update of recent research efforts outlining the state of progress in that area, and concluding with the

committee’s recommendations on resear ch needs and directions. The committee examined four major areas of research:

• transmission of influenza and other viral respiratory diseases and the use of PPE in preventing transmission (Chapter 2);

CONCEPT PROOF OF

PRINCIPLE STANDARD OF

PRACTICE

Basic Science

Research (Safety) Clinical and Applied

Research (Efficacy) Systems

Research (Effectiveness) Policy and Regulatory

Research (Disease Reduction

in Populations)

T4 T3 T2 T1

FIGURE 1-2 An integrated system moving research into practice, depicting the

translation of research from basic scien ce research (T1) through policy and regulatory research (T4). SOURCE: Adapted from Henderson and Palmore (2010) with permission from University of Chicago Press.INTRODUCTION 27

• design and engineering of PPE to be effective and wearable (Chapter 3);

• use of PPE by healthcare personnel (Chapter 4); and

• policy, standards setting, and certification (Chapter 5).

The report covers PPE issues that are relevant to preventing the transmission of a number of viral respiratory diseases; however, much ofthe recent research and discussion is focused on influenza and, as a result, influenza is the primary disease discussed in the report. The priorities noted throughout this report are to determine the type of PPE needed for given exposures and to move effective, wearable, and innovative PPE products through the basic research and initial testing phases and on to active use and evaluation by the worker community.

REFERENCES

BLS (Bureau of Labor Statistics). 2010. Career guide to industries, 2010-2011

edition: Healthcare . http://www.bls.gov/oco/cg /cgs035.htm (accessed November 19, 2010). CDC (Centers for Disease Control and Prevention). 2003. Cluster of severe acute respiratory syndrome cases among protected health-care workers— Toronto, Canada, April 2003. Morbidity and Mortality Weekly Report 52(19):433-436.

———. 2010a. The 2009 H1N1 pandemic: Summary highlights, April 2009- April 2010 . http://cdc.gov/h1n1flu/cdcresp onse.htm (accessed November 19, 2010).

———. 2010b. 2010-11 influenza prevention and control recommendations: Additional information about vaccination of specific populations . http:// www.cdc.gov/flu/professi onals/acip/specificpopula tions.htm (accessed November 30, 2010).

———. 2010c. Prevention strategies for seasonal influenza in healthcare
settings . http://www.cdc.gov/flu/professiona ls/infectioncontrol/healthcare settings.htm (accessed December 20, 2010). ———. 2010d. Respiratory syncytial viru s activity—United States, July 2008-

December 2009. Morbidity and Mort ality Weekly Report 59(8):230-233.

———. 2010e. Updated CDC estimates of 2009 H1N1 influenza cases, hospitalizations and deaths in the United States, April 2009-April 10, 2010

. http://www.cdc.gov/h1n1flu/estimates_2009_h1n1.htm (accessed November 19, 2010). Fiore, A. E., C. B. Bridges, and N. J. Cox. 2009. Seasonal influenza vaccines. Current Topics in Microbiology and Immunology 333:43-82.28 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Henderson, D. K., and T. N. Palmore. 2010. Critical gaps in knowledge of the epidemiology and pathophysiology of healthcare-associated infections. Infection Control and Hospital Epidemiology 31(Suppl. 1):S4-S6. IOM (Institute of Medicine). 2008. Preparing for an influenza pandemic: Personal protective equipmen t for healthcare workers . Washington, DC:

The National Academies Press.

———. 2009. Respiratory protection for healthcare workers in the workplace against novel H1N1 Influenza A: A letter report . Washington, DC: The

National Academies Press. Johnson, N. P., and J. Mueller. 2002. Updating the accounts: Global mortality of the 1918-1920 “Spanish” influenza pandemic. Bulletin of the History of

Medicine 76(1):105-115. Morens, D. M., and A. S. Fauci. 2007. The 1918 influenza pandemic: Insights for the 21st century. Journal of Infectious Diseases 195(7):1018-1028. NIOSH (National Institute for Occupational Safety and Health). 2007. Evidence for the National Academies’ review of the NIOSH personal protective technology program . http://www.cdc.gov/niosh/nas/ppt/pdfs/PPT_EvPkg_ 090707_FinalR.pdf (accesse d November 30, 2010). OSHA (Occupational Safety and Health Administration). 2002. OSHA fact sheet: Personal protective equipment . http://www.osha.gov/OshDoc/data_ General_Facts/ppe-factsheet.pdf (accessed November 30, 2010). Siegel, J. D., E. Rhineh art, M. Jackson, L. Ch iarello, and the Healthcare Infection Control Practices Advisory Committee. 2007. 2007 guideline for isolation precautions: Preventing transmission of infectious agents in healthcare settings . http://www.cdc.gov/hicpac/pdf/isolation/Isolation2007. pdf (accessed December 20, 2010). Thompson, M., D. Shay, H. Zhou, C. Bridges, P. Cheng, E. Burns, J. Bresee,

and N. Cox. 2010. Estimates of deaths associated with seasonal influenza— United States, 1976–2007. Morbidity and Mortality Weekly Report 59(33):1057-1062. Thompson, W. W., D. K. Shay, E. Weintraub, L. Brammer, C. B. Bridges, N. J. Cox, and K. Fukuda. 2004. Influenza- associated hospitalizations in the

United States. Journal of the American Medical Association 292(11):1333-

1340. Treanor, J. J., K. Kotloff, R. F. Betts, R. Belshe, F. Newman, D. Iacuzio, J. Wittes, and M. Bryant. 1999. Evaluati on of trivalent, live, cold-adapted (CAIV-T) and inactivated (TIV) influe nza vaccines in prevention of virus infection and illness following challenge of adults with wild-type influenza A (H1N1), A (H3N2), and B viruses. Vaccine 18(9-10):899-906.

## 2

Understanding the Risk

to Healthcare Personnel

Interest in the transmission of influenza viruses has increased in recent years due to the ongoing zoonotic infection of humans with avian H5N1 influenza viruses and the pande mic spread of a swine-like H1N1strain in 2009. In particular, the recognition that person-to-person transmission is a major criterion that must be met for pandemic infection has

stimulated research into the mechan isms by which influenza viruses are

transmitted and what factors enhance or interfere with this transmission. In considering preventive efforts to avoid viral respiratory disease transmission, the committee emphasizes the importance of the use of a range of hazard controls, including vaccination, to protect healthcare personnel. This chapter provides a synopsis of the discussion in the 2008 report regarding influenza transmission followed by an overview of recent (2007 to mid-2010) research on viral respiratory disease transmission.Studies on personal protective equipment (PPE) use to prevent viral respiratory disease transmission are also reviewed. The chapter concludes with the committee’s thoughts on imme diate research needs and longterm research opportunities.

BACKGROUND AND CONTEXT

FROM THE 2008 REPORT

The prior Institute of Medicine repo rt examined research studies conducted through 2007 on the modes of influenza transmission and highlighted the paucity of data on the relative contributions of each to the risk of illness in the community or clinical setting. A major challenge in research on this issue has been the lack of consistency in the use of terms

2930 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

to describe particle size and to describe potential transmission routes (Box 2-1). As research efforts move forward, agreement is needed on terminology to be used so that stud ies can be compared. Box 2-1 provides the definitions used by the comm ittee throughout the report, including in describing earlier studies. The term s and definitions of the transmissionroutes were developed at a recent Centers for Disease Control and Prevention (CDC) workshop (David Weissm an, personal communication, CDC, November 2010) and are provided as a starting point. These are operational

BOX 2-1 Terminology—Particle Size and Transmission Routes

As noted above, the terms and definit ions here are used to frame the discussion, and efforts are needed to r each consensus agreement among the many relevant areas of research and clinical care.

Particle Size:

• Respirable particles

— particles with d a ≤ 10 μ m that can be inhaled and penetrate to the alveolar region; although a substantial fraction deposit in the alveolar region, they deposit throughout the respiratory tract. These are the equivalent of “droplet nuclei.”

• Inspirable particles

— particles with 10 μ m ≤ d a ≤ 100 μ m, which can be inhaled but cannot penetrate to t he alveolar region; nearly all deposit in the head airways region.

Transmission Routes:

• Contact transmission:

o Direct contact transmission occurs when the virus is transferred by contact from an infected per son to another person without a contaminated intermediate object.

o Indirect contact transmission involves the transfer of viral agents by contact with a contaminated intermediate object.

• Droplet spray transmission: Person-to-person transmission of the virus through the air by droplet sprays. A key feature is deposition by impaction on exposed mucous membranes.

• Aerosol transmission: Person-to-person transmission of influenza or other respiratory viruses through the air by aerosols in the inspirable (inhalable) size range or smaller. Particles are small enough to be inhaled into the oronasopharynx and distally into the trachea and lung.

NOTE: d a = aerodynamic diameter. Terminology regarding particles with d a >
100 μ m is needed. SOURCES: Nicas and Jones (2009); Personal communication, D. Weissman,
November 2010.UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 31

definitions and are not CDC policy. The definitions of particle size are adapted from a set of definitions d escribed by Nicas and Jones (2009). Further work is needed on standardization of terminology. A common set of definitions accepted by the industrial hygiene, infectious disease, andhealthcare communities would be most helpful in discussing future research and policy. Much of the discussion regarding in fluenza transmission has focused on the continuum between droplet spray and aerosol transmission, as

well as on the role of contact transm ission and the potential for transmission through inoculation of the conjunctivae. Aerosol transmission, anissue in healthcare settings where patients have diseases such as tuberculosis and measles, can occur at a short range between persons but can also involve infectious agents carried for longer distances by air currents. Fabian and colleagues (2008) collected exhaled breath of patients with active influenza. In 4 of 12 subjects, exhaled breath contained influenza, and more than 87 percent of exhaled particles were < 1 μm.One of the main reasons why there is no clear understanding of longrange transmission is because aerosol transmission of influenza and other respiratory viruses is difficult to study in human populations. To study long-range aerosol transmission properly, the background prevalence ofthe disease would need to be low in the community, and many other factors would need to be controlled to rule out other transmission routes, such as droplet spray and contact (Tellier, 2009). Production of aerosols also varies by individual; some individuals produce large amounts of bioaerosols in coughs, sneezes, and even tidal breathing, while others do not. Therefore, some individuals may be more or less likely to transmit influenza infection or other viral respiratory diseases via aerosols. Context is likely to play an important role in shaping the importance of these transmission pathways in relation to illness occurrence. Researchers have shown that contextual factors may include environment,humidity, temperature, number and types of fomites, air flow, age of susceptible and infected populations, a nd number of individuals and their interactions within space. Biological factors that may influence transmission include virus strain characteris tics, human physiology, immune status, and genetic susceptibility of the host. Modifications to the living environment have the potential to reduce the transmission of influenza virus or other respiratory viral agents. These modifications include increasing the rate of air exchange, using non-recirculated air, irradiating air prior to recirculation, and changing absolute humidity (Lowen et al., 2007; Shaman et al., 2010). Increased32 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

air exchange is expected to affect transmission by an aerosol route through a reduction in the concentration of infectious particles in the air. Because both temperature and humidity are known to impact the stability of influenza viruses in an aerosol (Harper, 1961, 1963; Hemmes et al.,1960; Schaffer et al., 1976), interventions to reduce transmission by altering these environmental conditions may be useful.

Influenza A transmission has been st udied in various animal species— including mice, guinea pigs, monkeys, and ferrets—with variable results. These studies show that animals develop influenza infection, and mostdemonstrate the possible role of aerosol transmission. Experiments performed in the 1930s demonstrated that influenza virus–naïve, asymptomatic ferrets that were caged with in fluenza virus–infected ferrets wouldsubsequently develop disease and that, even in the absence of experimental infection, ferrets occasionally di splayed an influenza-like illness, after which they became immune to subse quent virus inoculation (Francis and Magill, 1935; Smith et al., 1933). Andrewes and Glover (1941) demonstrated transmission using an experimental design in which air flowed from infected to naïve ferrets through a tube containing S- and U-shaped bends, which would be expected to allow the transfer of only small (< 5 μ m) respirable particles. In hamsters, by contrast, transmission of influenza viruses appeared to depend on contact between infected and exposed animals (Ali et al., 1982). A seri es of experiments with mice in the 1960s also provided some evidence suggesting aerosol transmission (Schulman, 1968; Schulman and Kil bourne, 1962). More recently, the guinea pig has been successfully used to study influenza transmission (Lowen et al., 2006). Transmission among humans has been studied less. Early volunteer studies found that infection via inhalation of respirable particles requires considerably less virus than infec tion via droplets placed on the nasal membranes (Alford et al., 1966; Couch et al., 1971, 1974; Douglas, 1975). Several observational studies of naturally occurring influenza provided insights into the challeng es of studying transmission modes.One of the most well-known incidents of an influenza A outbreak happened among passengers on a grounded ai rplane (Gregg, 1980; Moser et al., 1979). An observational study of 49 passengers delayed on a 737 jet for 3 hours and exposed to an index case with influenza suggested aerosol transmission. Within 72 hours, 72 percent of the passengers became ill. Specimens from 31 of the 38 cases were cultured and found to have

similar isolates. A second airline tr avel–associated outbreak also suggested aerosol transmission with a 37 percent attack rate and wide seat-UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 33

ing distribution of secondary cases throughout the aircraft (Klontz et al., 1989). More recent studies of airline travel indicate close-proximity transmission (Baker et al., 2010; Han et al., 2009; Ooi et al., 2010), which could occur via one or more routes. Newer airplanes have morelaminar air flow and improved filters over older planes, which may reduce long-range aerosol transmission. Studies examining how air flow may help prevent transmission of viral respiratory diseases in closed and crowded settings, such as an airplane, are warranted.Wong and colleagues (2010) recently reported a nosocomial outbreak of seasonal influenza in an acute -ward setting that appeared to be attributed to aerosol transmission. An aerosol-generating device was used on the influenza index case patie nt. At the same time, the authors

identified an imbalance in the indoorairflow that likely created a directional dispersion of air and potentially carried influenza aerosols to other areas of the ward. Other patients were infected following a temporal and spatial pattern of air flow originatin g from the index patient. Two of the staff also became ill even though they were required to adhere to strict hand hygiene and medical mask use.

Additional observational studies of human influenza have provided further descriptions of influenza outbreaks, but the findings do not clarifypotential mechanisms of transmission (discussed in IOM, 2008). For example, Drinka and colleagues (1996, 2004) compared influenza rates in several buildings of a long-term care facility during several seasons of influenza. Their initial study found that persons working in buildingswith ventilation systems that provided outside air had much lower infection rates than those working in buildings with partially recirculated air(Drinka et al., 1996). However, an update of this study found similar infection rates (Drinka et al., 2004). Reviews of other reported influenza outbreaks suggest droplet spray and contact transmission routes based on temporal and spatial patterns (Brankston et al., 2007; Cunney et al., 2000; Drinka et al., 1996; Morens and Rash, 1995).

Studies of the clinical effectiveness of PPE have had mixed results inpreventing severe acute respiratory syndrome (SARS) or respiratory syncytial virus (RSV) infections (see Appendix C). Challenges in studies of this type include difficulties in retr ospectively separating the effects of

PPE from the effects of other infection control measures. Specific issues regarding respiratory disease transmission to healthcare personnel have focused on medical procedures that have a potentialfor creating aerosols, and data are primarily available for SARS, not influenza. Fowler and colleagues (2004) observed a greater risk of devel-34 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

oping SARS for physicians and nur ses performing endotracheal intubation. Similarly, in a retrospective study of 43 nurses who worked in Toronto with SARS patients, Loeb and colleagues (2004) found thatassisting during intubation, suctioning before intubation, and manipulating the oxygen mask were high-risk activities for acquiring SARS; wearing a face mask or N95 respirator was protective. As stated throughout the 2008 report, establishing how influenza istransmitted and understanding the contribution of each mode of transmission is critical to preventing its spread and reducing morbidity and mortality due to influenza infection, especially in healthcare settings. The 2008 report outlined a number of questions that remained to be addressed regarding influenza transmission (IOM, 2008):

• Questions regarding transmission mode, including: What are the major modes of transmission? How much does each mode of transmission contribute individually or with other modes of transmission? What is the size distribution of particles expelled by infectious individuals, and how does that continuum of sizes affect transmission? Is the virus viable and infectious on fomites, and for how long? Are fomites a means of transmission, and are

some more able to transmit than others?

• Questions regarding infectivity, including: Can infection take place through mucous membranes or conjunctiva exposure? What is the time sequence of infectivity?

• Questions specific to transmissi on in healthcare settings, including: What activities in the healthcare setting are associated with

minimal or increased transmission? How distinct is transmissionin different venues including health care, schools, and households?

• Questions specific to the role of PPE in preventing or reducing transmission, including: How effective is each type of PPE in reducing the risk of influenza transmission? How effective are

face masks? What innovations re garding PPE are needed to enhance effectiveness? What is the impact on transmission risk when patients wear face masks?

• Questions specific to other potential forms of prevention, including: What is the role of ultraviolet (UV) light, humidity, temperature, pressure differentials, air flow and exchange, and ventilation in preventing transmission?UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 35

The 2008 report concluded its discussion regarding research on influenza transmission with a recommendation that a Global Influenza Research Network should be initiated an d supported. This network would facilitate an understanding of the tr ansmission and prevention of seasonal and pandemic influenza, with priority funding given to short-term clinical and laboratory studies. Furthermore, the recommendation stressed the need to develop rigorous, evidence-ba sed research protocols and implementation plans for clinical studies for use during an influenza pandemic (IOM, 2008).

UPDATE ON RECENT RESEARCH

In the 3 years since the writing of the prior report (IOM, 2008), research efforts continue to examine the various routes of transmission and explore approaches to preventing transmission. The following sectionprovides an overview of recent research (2007 to mid-2010) and describes animal studies, environmental monitoring and persistence studies, transmission modeling studies, and human studies. The literature

searches on disease transmission conduc ted by the committee focused on influenza. Searches of bibliographic databases for studies on PPE use

and transmission were broader and in corporated other viral respiratory diseases; only a few recent studies on other viral respiratory diseases were identified, however, and those are discussed and referenced in this

report.

Animal Studies

Animal models complement epidemiological approaches by allowing

the examination of influenza virus transmission from an infected to a susceptible host under well-controlled conditions. The ferret and guinea pig models are the current models of choice in influenza studies. Ferrets are naturally susceptible to infection with human influenza viruses, andthese viruses transmit among them, making the ferret the current goldstandard animal model for the study of influenza. Prompted by the need for a more convenient animal model than the ferret in which to study transmission, the guinea pig was recently developed as such a model host(Lowen et al., 2006). Although signs of disease are generally not observed in influenza virus–infected guinea pigs, these animals are highly36 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

susceptible to infection with human strains, and human influenza viruses transmit efficiently from one guinea pig to another.

Animal Models on Modes of Transmission

The relative contributions of the various modes by which influenza viruses transmit is currently a subject of debate in the field. In the context of experimental studies using animals, transmission by the contact route is normally modeled by placing infected and naïve animals into the same cage together. It is important to note, however, that this set-up does not allow one to distinguish transmission by a contact route from short-rangespread mediated by an aerosol. To study transmission specifically by inspirable or respirable aerosols, animals are placed into separate cages so that air exchange can occur among them , but they cannot touch. Although this arrangement rules out contact- based transmission, when cages areplaced in close proximity (as is usually the case), transmission may proceed via the droplet spray or aerosol modes. Transmission of human seasonal and 2009 H1N1 pandemic strains among either ferrets or guinea pigs oc curs efficiently using both experimental designs, indicating that transmission among ferrets and guineapigs can proceed in the absence of direct or indirect contact among animals (recent studies include Lowen et al., 2006, 2007, 2008; Maines et al., 2009; Munster et al., 2009; Steel et al., 2010; Tumpey et al., 2007). In addition, evidence for transmission of influenza viruses by the aerosol

route has been obtained in the ferre t and guinea pig models; early workin ferrets (Andrewes and Glover, 1941) and recent experiments performed in guinea pigs (Mubareka et al., 2009) demonstrate transmission over a distance of up to 3.5 feet. Recent attempts to model influen za virus transmission in BALB/c mice have been unsuccessful (Lowen et al., 2006); nevertheless, a mouse model was used by Schulman and Kil bourne to study transmission in the 1960s (Schulman, 1968; Schulman and Kilbourne, 1962). Because of the inefficiency of transmission and the low susceptibility of mice to human

influenza viruses that have not been ser ially adapted in this host, currently the mouse model is not used widely for research on influenza virustransmission. Hamsters are also not in widespread use as a model for influenza virus infection, but Ali and colleagues (1982) showed that certain

human influenza isolates transmitted well when infected and naïve ham-UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 37

sters were housed in the same cage; transmission in the absence of contact was not, however, observed. The potential for contact with cont aminated surfaces to mediate influenza virus transmission among guinea pigs was examined by Mubareka and colleagues (2009). Naïve guinea pigs were placed in cages that either had previously housed an acutely in fected animal or had been contaminated with high titers of influenza virus through direct application onto non-porous cage surfaces. In the former case, approximately 20 percent of exposed animals contracted infection, while with the latter design, no exposed animals became infected (Mubareka et al., 2009). When these results are compared to the high efficiency of transmission of the same virus by the aerosol route, they su ggest that—at least in the guinea pig model—spread via fomites makes a minor contribution to the overall

transmission of influenza viruses.

Relationships Between Transmission and Symptoms, Timing Post-Infection, and Shedding Titers

Because of their potential to pro duce infectious aerosols, coughing and sneezing are generally thought to promote transmission (Tumpey et al., 2007). Evidence against a critical role for sneezing and coughing arises from the guinea pig model: Although these animals do not sneeze or cough following influenza virus infection, viral spread is efficient among guinea pigs (Lowen et al., 2007). Influenza viruses have been isolated from the air surrounding infected guinea pigs (Mubareka et al., 2009) and even mice (Schulman, 1967); this virus is most likely expelled into the environment through normal breathing (Fabian et al., 2008).The timing of transmission events relative to initial infection of donor animals has not been examined cl osely (through the use of defined exposure periods) in the ferret or gui nea pig models; the serial collection of nasal wash samples over the cour se of exposure does, however, allow an estimate of the time of transmission to be made. In the guinea pig model after exposure by contact and aerosol routes, virus was detected initially in the nasal washings of exposed animals at 1–3 days and 3–5 days, respectively (Lowen et al., 2006, 2007, 2008, 2009; Steel et al., 2009). The infection of exposed ferrets occurs with similar timing by

contact and aerosol routes: Initial det ection of virus in the nasal passages of exposed animals usually occurs between 1 and 3 days post-exposure (Itoh et al., 2009; Maines et al., 2006, 2009; Tumpey et al., 2007). Varia-38 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

tions in transmissibility among differing strains of influenza viruses do not show a strong correlation with di fferences in peak shedding titers (Maines et al., 2006, 2009; Mubareka et al., 2009; Steel et al., 2009; Tumpey et al., 2007), suggesting that, although efficient growth in the upper respiratory tract is most likely required for an influenza virus to transmit, additional criteria must be met for transmission to proceed.

Relative Transmissibility of Influen za Viruses Derived from Different Host Species

Viral strain and subtype specific differences in influenza virus

transmission have been observed in recent studies of animal models. One strength of both the ferret and guinea pig models is that influenza viruses adapted to human hosts generally tran smit more efficiently than avian-, swine-, or mouse-adapted strains. Thus, the low pathogenic avian strains A/duck/Alberta/35/1976 (H1N1) a nd A/duck/Ukraine/1963 (H3N8) did not transmit among guinea pigs, while certain highly pathogenic H5N1

influenza viruses have been observed to transmit among co-caged guinea pigs to a limited extent (Gao et al ., 2009; Steel et al., 2009). Swine influenza isolates of the H3 subtypes tr ansmitted with 25 percent efficiency by the aerosol route among guinea pigs (Steel et al., 2010). By contrast,human H3N2 subtype viruses, as well as the H1N1 pandemic strain, generally transmit to all exposed guinea pigs by either contact or aerosol routes (Lowen et al., 2006; Steel et al., 2010). Overall, seasonal H1N1subtype viruses have been found to transmit less efficiently among guinea pigs than epidemic strains of the H3N2 subtype (Mubareka et al.,2009). A similar pattern of transmissibility is observed in the ferret model: Avian influenza viruses do not transmit to exposed animals by an aerosol route (Tumpey et al., 2007; Van Hoeven et al., 2009), but some low and highly pathogenic strains do transmit by contact to a limited extent (Belser et al., 2008; Maines et al., 2006; Sorrell et al., 2009; Van Hoeven et al., 2009; Wan et al., 2008). Human seasonal strains of both H3N2 and H1N1 subtypes transmit readily among ferrets (Itoh et al., 2009; Maines et al., 2006, 2009; Wan et al., 2008), and the pandemic

H1N1 strain has been observed to tr ansmit with similar efficiency (Itoh et al., 2009; Munster et al., 2009) or somewhat lower efficiency (Maines et al., 2009) by an aerosol route than seasonal influenza viruses.UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 39

Interventions: Blocking Influenza Virus Transmission in

Animal Models

Interventions that offer the potential to limit transmission of influenza viruses in healthcare settings incl ude vaccination; the prophylactic and therapeutic use of antiviral drugs; non-pharmaceutical interventions, suchas the use of good hand hygiene and PPE; use of source control; cohorting the patients; and modifications to the indoor environment. Changes in transmission achieved through vaccination were studied in the guinea pig model, and it was found that transmission could be abrogated through

vaccination. This was the case whether the vaccinated animals were the donors or recipients in the transmission experiment. Vaccination was particularly effective in blocking spread if sterilizing immunity was achieved (as was seen using a live attenuated vaccine), but transmission was also reduced following suboptimal vaccination 1 (Lowen et al.,2009). Also in guinea pigs, twice-daily treatment with oseltamivir reduced titers shed from the upper respir atory tract of treated donor guinea pigs and, in turn, prevented transmission to untreated aerosol contacts. This is similar to recent and past studies of prophylactic treatment of household contacts of infected persons that has been found to be very effective (Halloran et al., 2007; Hayden et al., 2000, 2004; Monto et al., 2002; Welliver et al., 2001). Research in the past several years has demonstrated in the guinea pig

model that transmission between anim als in separate cages occurs with lower frequency (or not at all) when the surrounding air is warm (30°C) or maintained at high (80 percent) or intermediate (50 percent) relativehumidities (Lowen et al., 2007, 2008). Although field studies are required to translate these findings to th e human situation, they suggest that the modification of relative humidity in healthcare settings may be a means of controlling the spread of in fluenza virus infection. The impact

of UV treatment of air on influenza vi ral spread has not been assessed in an animal model; if transmission proceed s at least in part by an aerosol route, however, such treatment is expected to be effective.

1 The authors describe suboptimal vaccines as those that may provide only partial protection against the disease but are effective at limiting transmission (Lowen et al., 2009).40 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Environmental Monitoring and Persistence Studies

Air Monitoring

To learn more about the distribution of aerosol influenza virus in an urgent care setting, two studies have recently been conducted. A study by Blachere and colleagues (2009) of real-time polymerase chain reaction (RT-PCR) identified the presence of aerosolized influenza in several areas of an emergency department , including a waiting room, a reception area, and personal samplers placed on physicians. On 3 of 6 separate days, aerosolized influenza A virus was detected. Half of the influenza particles were found to be in the respirable size range. The follow-up study by Lindsley and colleagues (2010a) looked at both influenza and RSV. Seventeen percent of the stationary samplers contained influenza Aribonucleic acid (RNA), and 32 percent contained RSV. Nineteen percent and 38 percent of clinical sta ff samplers contained influenza A and RSV RNA, respectively. A correlati on was found between samplers thatcontained influenza and presence of patients who were positive for influenza (r = 0.77). A slightly smaller proportion of the influenza A RNA was in particles ≤ 4.1 μm in aerodynamic diameter (42 percent) compared with the earlier study by Blachere and colleagues (2009) (53 percent). These studies indicate that aerosolized particles exist in thisspecific urgent care setting. However, the viability of the influenza viruses was not ascertained, and therefore it is not possible to quantify the importance of the identified aerosol pa rticles to transmission in the hospital setting. A recent study by Lindsley and colleagues (2010b) showed that 84 percent (32/38) of influenza-positive patients had influenza viral RNA in their cough aerosols as identified by a National Institute for OccupationalSafety and Health two-stage bioaerosol cyclone sampler or an SKC BioSampler. Of the influenza viral RNA detected, 65 percent was containedin particles in the respirable range (< 4 μm), suggesting that these particles could be inhaled and deposited in the alveolar region of the lungs.Viable virus was detected in the cough aerosols of some infected patients. A limitation of the collection system was the inability to collectlarger particles. Therefore, this study was unable to quantify the proportion of small versus large particles or the total amount of viral material contained in the cough of an influenza-infected patient.UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 41

Fomite Persistence

Studies examining fomite contamination have focused largely on virus survivability on environmental su rfaces. The type of fomite surface appears to play a significant role in influenza virus survival with low survival times on porous materials, such as paper and cloth, ranging from 8 to 12 hours and on non-porous materials, such as stainless steel andplastic, ranging from 24 to 72 hours (Boone and Gerba, 2007). Other factors likely to affect survival of influenza on fomites include cleanliness and moisture. In experimental st udies reviewed by Boone and Gerba,transfer of influenza virus to the hands occurred up to 24 hours after contaminating stainless steel fomites with influenza virus. Hands appear notto be a very hospitable environment for influenza, with viral decay occurring within the first 5 minutes of fomite-to-hand transfer. Nonetheless, if hands are continually inocul ated by a touch to contaminatedfomites, direct infection is likely. In the case of commonly touched fomites, influenza virus may be transfe rred from the fomite to the hands of a human host through consistent contact . As noted in an earlier study, among clinicians, 1 in 3 healthcare professionals rubbed their eyes and42 percent picked their nose per 1-hour observation, suggesting that selfinoculation of influenza virus among these healthcare personnel would be likely if hands became contamin ated in the hospital environment (Boone and Gerba, 2007; Hendley et al., 1973). The significance of fomites in the spread of respiratory disease has been assessed through experimental seeding studies and assessments of inactivation rates (Boone and Gerba, 2007). Of the inactivation rates reviewed across a range of respiratory viruses (rhinovirus, RSV, coronaviruses, parainfluenza virus, avian influenza, and influenza A and B viruses), avian influenza and influe nza A viruses had the lowest log 10 reductions per hour. The log 10 reduction per hour on non-porous fomites were 22 and 45 times lower for avian influenza and influenza A virus, respectively, compared to RSV, which had the highest log 10 reductionper hour on surfaces. The only other respiratory virus with similar survivability as influenza on non-porous surfaces was rhinovirus, which can

also survive for more than 24 hours. Avian influenza virus, in particular, was shown to have high survival rates on both porous and non-porous surfaces, including stainless steel, latex gloves, and cotton—as long as 144 hours. Survival on fomites, therefore, is much longer than what has

been observed for human influenza su rvival in artificially produced aero-42 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

sols, where rates ranged from 6 to 16 hours (Brankston et al., 2007; Mitchell and Guerin, 1972; Mitchell et al., 1968). In a recent experimental study, coronavirus was detected on PPE at a minimum of 4 hours following initial exposure (Casanova et al., 2010). N95 respirators, contact isolation gow ns, and latex gloves all had detectable virus 24 hours after exposure. The authors concluded that coronaviruses were able to survive on hospital PPE longer than the duration of contact with an infected patient. Far fewer observational studies have been done on influenza and other respiratory viruses on surfaces and PPE in the clinical setting. There are some developments in antimicrobial masks, but the utility and risks associ ated with these embedded materialsare unclear. For example, Li and colleagues (2006) examined the antimicrobial activity of nanoparticle material with a mixture of silver nitrate and titanium dioxide for reducing bacteria on N95 respirators. There were large reductions in S. aureus and E. coli after 48 hours of incubation, but whether this material woul d have any activity against influenza was unclear because no respiratory viruses were tested in the study (Li et al., 2006). Macias and colleagues (2009) examined the extent of 2009

H1N1 contamination on the hands of healthcare personnel and patients and on environmental surfaces in a hospital in Mexico. The computer mouse, hands, and bed rails were all found to be positive for the influenza virus, but viability of the virus was not assessed. Studies have also

examined the role of the contact tran smission route in the transfer of rhinovirus and RSV (Gwaltney et al., 1978; Hall et al., 1980, 1981). Taken together, these experimental and observational studies support a role for the contaminated environment and PPE as a potential source of viable respiratory viruses, such as influe nza. Nonetheless, no recent studies identified by the committee have exam ined whether infection can be transmitted directly from contact with a contaminated fomite.

Inactivation of Influenza A Viruses

A review by Weber and Stilianakis (2008) examined studies on the inactivation of influenza A viruses in the environment and the impact on modes of transmission. Currently little is known about inactivation of influenza virus. Experimental studies indicate that low relative humidity in heated indoor areas promotes influe nza survival in the closed environment. However, the converse relationship has been observed outside of the United States, where outbreaks have occurred in tropical regionsUNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 43

during hot and rainy months. Relative humidity does not independently predict virus survivability. Because of the variability in global outbreak patterns by relative humidity, some have argued that contact transmission may predominate in tropical climates whereas aerosol transmission ismore common in temperate climates (Lowen and Palese, 2009). Modeling studies support a role of humidity in predicting disease outbreaks. Shaman and colleagues (2010) report that absolute humidity provided a robust correlate for seasonal variation in temperate climates.

Transmission Models

Although empirical studies have show n that influenza transmission is feasible by aerosol, droplet spray, and contact routes, the results of these studies have not provided a comprehe nsive understanding of the relative contribution of each mode in causing outbreaks. Mathematical modelscan be used as a method for testing hypotheses about the spread of respiratory infections (Brauer, 2009). Not all components of disease spread are measured in these models, but important parameters can be identifiedand estimated. Unfortunately, the lack of basic scientific data on transmission and survivability of influenza makes it very difficult to accurately determine the parameters for these models or to assess the fit of these models with available data. Many transmission models looking at the spread of influenza and other respiratory diseases include simulationsthat provide varying estimates on different modes of transmission, including the case reproductive number (R 0 ), social patterning, susceptibility, and influenza strain characteristics. The following summary of recent research in this area focuses on the key findings and assumptions inherent in these models in a way that may apply to healthcare personnel. Multiple modes of influenza transmission have been explored using modeling information. Potential s ources of influenza transmission to healthcare personnel through commun ity and nosocomial exposures have

also been modeled.

Models of the Dynamics of Influenza Transmission

Nicas and Jones (2009) examined the contribution of four modes of influenza transmission: hand contact; respirable particles (cough particles < 10 μm in diameter); inspirable particles (cough particles 10–100 μm in44 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

diameter); and droplet spray (> 100 μm in diameter). This study used two very different assumptions regarding in fectivity: (1) the ratio of infectivity was 3,200:1 for influenza virus deposited in the lower respiratory tract compared to the upper respiratory tract, and (2) the ratio of infectivity was 1:1 for influenza virus deposited in the lower respiratory tract versus the upper respiratory tract. The infectivity ratio assumptions played a major role in determining which method of transmission was most likely to cause disease. Assuming a 3,200:1 infectivity ratio for influenza virus deposited in the lower respiratory tr act compared with the upper respiratory tract, droplet spray accounted for 58 percent of the infection risk at low salivary viral concentrations, comp ared to 27 percent of the risk for fomite or hand contact and 14 percent of risk from respirable particles.

Little is known about virus saliva c oncentrations in humans, which may vary widely. As the salivary viral concentration increased, the risk of infection from droplet spray decreased, while the importance of hand contact in spreading disease increased. However, with a 1:1 ratio of infectivity inthe lower versus upper respiratory tract, hand contact was the major driver of infection across all viral salivar y concentrations (Nicas and Jones, 2009). The main measures assessed for reducing the risk of influenza transmission in the healthcare setting included hand washing, disposable gloves, and face masks to reduce t ouching the face. Measures for preventing infection caused by droplet spray included fluid-resistant masks and eye goggles or face shields. Besides social distancing, the modelfound that the most effective way to reduce respirable and inspirable particles included the use of an N95 filtering respirator and/or increasing the room ventilation. When the model used an infectivity ratio of 1:1, the research found that if influenza-pos itive individuals have a low concentration of salivary virus, healthcare personnel can significantly decrease the risk of transmission through simple methods, such as hand washing, standard surgical face masks with gogg les, or face shields. At an infectivity ratio of 3,200:1, respirable particles would make up a substantial part of the risks, and respirators would be required. Chen and colleagues (2009a) speci fically assessed the dynamics of aerosol influenza transmission and found the volume of particles released from a sneeze were approximately th ree-fold higher than for a cough.Using an equation to estimate the total volume of particles had the following results: with cough, the highest volume occurred with a particle sized 5.8 μm (which would be classified as respirable particles by Nicas and Jones [2009]), leading to a volume of virus of 500 × 10 –10 mL, andUNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 45

26 μm for sneeze (classified as inspirable particles by Nicas and Jones),

with a volume of virus of 3 × 10 –7 mL. The predicted tissue culture infective dose 50 (TCID 50 ) for influenza was estimated to be 0.57 at 5.5 μm per cough 2.6 days after infection, and 264 per sneeze at 10 μm after 2.6 days. This model suggests that the TCID 50 produced by a sneeze is higher than that emanating from a cough.

A model of the risk of aerosol tr ansmission was examined in the setting of a commuter train. Assuming the inhalation of aerosol infectious agents during a commute, the estimated R 0 was found to be 2.22 (geometric standard deviation [SD] = 1. 53), with a specified number of air ventilation cycles per hour (Furuya, 2007). An exposure time of less than 30 minutes was found to reduce the likelihood of transmission, as weresurgical masks to reduce droplet spray transmission (assuming a reduction in the risk of contaminated air inhaled by 40 percent), and highefficiency particulate air masks (assuming a reduction in contaminated air inhaled by 97 percent) to reduce smaller particulate transmission. Of significance for healthcare personnel, do ubling the number of air ventilation cycles per hour was found to reduce the risk of infection to R 0 = 1. Although not all healthcare settings ar e comparable to the close and extended proximity found on a commuter train, the effectiveness of increasing the number of air ventilation cycles per hour may be useful for reducing the likelihood of inhalation e xposure to aerosol particles in the clinical setting. Other factors to consider in addition to ventilation would be the number of windows, number of stops, opening and closing of doors, and movement of people.

Models of Household Transmission

Household transmission models may be useful as a proxy for transmission within the healthcare setting. A single household model with two bedrooms and a common living quarter was used to assess the likelihood of influenza infection (Atkinson and Wein, 2008). The model included one infected individual, one primary caregiver, and two other householdresidents. The authors assumed that the death rate (rate of viral inactivation) on porous surfaces was more than one magnitude higher than the death rate on non-porous surfaces (0. 12 per hour versus 1.78 per hour). The death rate of virus in the air was estimated to be 0.36 per hour. The

authors assumed viral transmission occurred from the infected individual to the caregiver only within the infected individual’s room, through un-46 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

protected aerosol transmission with no deposition on surrounding surfaces. Transmission was assumed through close contact at the time of the infected individual’s emission, and that aerosol virus would be deposited on either porous or non-porous surfaces. The authors then compared totalinfluenza virus shed, infectious dose likely to infect half of the population, and death rate of the viruses on different surfaces between influenza virus and the rhinovirus. They found a higher total shed virus (1.93 × 10 5

TCID 50 compared to 1.57 × 10 5 TCID 50 ), higher TCID 50 required for respiratory epithelium (0.671 TCID 50 compared to 0.216 TCID 50 ), and much higher TCID 50 for nose and eyes (500 TCID 50 compared to 0.032 TCID 50 ) for influenza compared to rhinovirus. Although the death rate on hands was much higher for the influenza viru s (55.3 per hour) compared to rhinovirus (0.61 per hour), the death rate on porous and non-porous surfaceswas lower for influenza than rhinovirus. Atkinson and Wein (2008) concluded that aerosol transfer was the most likely mode of infection in the described setting.

Models of Healthcare-Associated Infection

The committee was unabl e to identify any studies since 2007 that modeled transmission of influenza within the hospital setting among healthcare personnel. Earlier, Nicas and Sun (2006) modeled the risk of transmissible respiratory diseases in a healthcare setting. The authorsprovided an integrated method of examining transmission between infected individuals, contaminated e nvironments, and direct patient-tohealthcare worker exposure, which could be used as a template for an influenza-specific model in the healthcare setting.

Models of Asymptomatic Carriers

The role of asymptomatic carriers in spreading influenza was examined using a Susceptible Exposed Infective Recovered model, with two additional categories: asymptomatic and hospitalized (Hsu and Hsieh, 2008). The model assumed that exposed individuals could either become infectious, and then move to ward a hospital or recover withouthospitalization, or become asymptomatic, and spread disease before recovering. Building on previous literature that up to a third of all influenza cases are asymptomatic, the authors assumed that asymptomaticUNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 47

individuals contributed less to viral shedding as a result of a decrease in symptoms, such as coughing, that ma y spread disease. The authors found that the way that the public responds to information about an outbreakcan reduce the number of influenza infections. However, due to asymptomatic influenza infections, community response alone cannot affect the basic dynamics of the model without additional steps, such as quarantine or other intervention measures, which were not included in the model because of additional complexities in thei r basic model. Therefore, with an asymptomatic subpopulation that is shed ding virus, influenza can continue to persist within the community even with an R 0 of less than 1.

Human Challenge, Observational, and Clinical Studies

Infectivity, Viral Shedding, and Symptoms

The timing of infection and quantity of viral shedding obviously play a role in the spread of influenza. A meta-analysis of 56 volunteer challenge studies attempted to quantify the time of peak viral shedding among healthy human volunteers (Carrat et al., 2008b). Two different

strains of virus were examined: in fluenza A/H1N1 strains (recovered earlier than 2009 H1N1) and influen za A/H3N2. In human volunteers, viral shedding showed a quick incr ease the first day following inoculation, with a maximum value reached after 2 days, and a return to baseline, on average, 8 days following inoculation. The first signs of shedding were observed in 83 percent of subjects 1 day after inoculation, 14 percent of subjects 2 days after i noculation, and 3 percent of subjects 3 days after inoculation, with an average duration of 1.1 days until viral shedding occurred. The mean duration of viral shedding was 4.80 days(95% confidence interval [CI] = 4.31, 5.29), with no significant difference in duration between H1N1 and H3N2 strains. One dose-varying study included in the meta-analysis found that shedding duration was dependent upon the initia l inoculation dose. Consistent with previous findings , Carrat and colleagues (2008b) determined that an average of 66.9 per cent of influenza-inoculated participants showed clinical symptoms. Total symptom scores peaked 2 to 3 days after inoculation, and returned to baseline after 8 days. The mean duration of illness was 4.4 days (SD = 1.8 days). The curves plotted for influenza viral shedding and symptom severity were similar, with viral48 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

shedding peaking 1 day prior to clinical symptoms. However, limited information across the studies was provided on the participants who did not develop clinical illness. The aut hors concluded that viral sheddingpeaked rapidly and that symptoms for influenza-like illness varied widely, making an influenza-like illness case definition unreliable for identifying infectious individuals to implement control measures. Moreover, the study populations were adults a nd generally healthy. Thus, variability in age, immune status, and underlyi ng health conditions may have profound effects on these estimates, as has been observed recently for 2009 H1N1 (Goodman, 2009). For example, children under age 9 infected with 2009 H1N1 shed virus for a median duration of 6 days after fever was detected, 1 day longer than overall median duration for all age groups, and some children showed signs of shedding for up to 13 days (Goodman, 2009). Historically, controlled viral cha llenge studies have provided key insights on respiratory virus transmission (Carrat et al., 2008a). Current preliminary efforts to develop influenza voluntary challenge studies areunder way in the United Kingdom and may provide an opportunity to better understand the relative contribution of differing transmission modes of influenza (Van-Tam, 2010). A household model of transmission of pandemic 2009 H1N1 virus found an average time between symptom onset of the primary case and secondary cases to be 2.6 days (95% CI = 2.2–3.5 days), similar to previous reports of time of disease spread between household members, but shorter than the secondary infections reported below (Cauchemez et al.,2009). Another study that recruited index patients to study the serial interval of influenza leading to a sec ondary infection within the household found the period to be longer than previously reported: an average of 3.6days (95% CI = 2.9–4.3 days). The interval measured time from symptom onset in a laboratory-confirmed case of influenza to the time of symptom onset in a corresponding household contact (Cowling et al.,2009b). More recently, Lau and colleagues (2010) used a communitybased study of households to show that the bulk of viral shedding happened during the first 2 to 3 days after illness onset and only 1 to 8 percent of infectiousness occurs prior to symptom onset. Moreover, only 14 percent of cases that had RT-PCR–detectable influenza virus RNA were asymptomatic, and the quantity of viral particles was low among these cases, suggesting that asymptomatic cases are unlikely to play a large

role in transmission.UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 49

An observational study examined influenza and rhinovirus infections among healthcare personnel. Bellei and colleagues (2007) collected both acute respiratory illness reports and laboratory samples among healthcare personnel. Nearly 50 percent of staff reporting influenza-like illnesses

had rhinovirus rather than influen za. Thus, surveillance by symptomsmay not accurately predict influenza viral activity among healthcare personnel. Influenza vaccination in this study population was low (19.7 percent), and varied by the departme nt where hospital personnel wereassigned. Of the 203 personnel recruited with any acute respiratory illness symptom, 48.3 percent reported direct contact with a patient, and 39.4 percent had preschool children expos ure either at the hospital or at

home.

Disease Transmission

In a recent study in an infant ward, of 122 susceptible patients with single rooms, only 6 (5 percent) acquired influenza in the ward, while 17 percent (13/77) of infants in a mu ltiple-crib room acquired nosocomial infection (Hall, 2007). Overall, child ren with one or two roommates were nearly 4 times more likely to acquire influenza in the hospital (odds ratio = 3.90, 95% CI 2.88–4.92). The author notes that one to three separate influenza cases occurred before peak influenza activity began over the two influenza seasons that were studied, and that neither of these cases was followed by a quick outbreak in the ward. Similarly, novel data examining outbreaks of 2009 H1N1 in airplanes, buses, and schools primarily implicate close proximity transmission (Baker et al., 2010; Han et al., 2009; Kar-Purkayastha et al., 2009; Ooi et al., 2010). In a review by Chen and colleagues (2008), transmission routes ofSARS were examined. Major transmission modes that have been demonstrated include close contact via droplet spray or contaminated fomites with respiratory excretion. In add ition, diarrhea accompanied infection and SARS virus was found in the greatest quantities in feces compared to nasopharyngeal and urine samples 14 days after first onset of symptoms.

Avian influenza H5N1 virus has been studied in several family clusters, and both droplet spray and cont act with stool have been hypothesized as important transmission routes. In a household cluster study byWang and colleagues (2008), an index case (the son) transmitted the infection to his father while his father cared for him in the hospital. The index case had large amounts of s putum, frequent coughing, and watery50 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

diarrhea with H5N1 infection. His father had no known exposure to poultry or other ill individuals. Neither the index case’s mother nor girlfriend, both of whom also had close contact, became infected. Transmission tothe father may have occurred through inhalation of respirable or inspirable particles or contact with feces-contaminated clothes. Of note, 2009 H1N1 illness symptoms also included vomiting and diarrhea (Bryant et al., 2010; Riquelme et al., 2009). Research on the potential for fecal oral

transmission of 2009 H1N1 influenza is warranted.

PPE Use to Prevent Respiratory Disease Transmission

Models on the Use of PPE

The effectiveness of surgical masks and N95 respirators in reducing the spread of influenza were direc tly modeled as a method of preventing the 2009 H1N1 (Tracht et al., 2010). Considering that the likelihood ofwearing a surgical mask or respirator can vary by many factors, including age and marital status, the authors assumed that compliance with the recommended intervention would only occur in the closed population when a minimal level of susceptible individuals became infected, and that individuals within the population could switch between wearing and not wearing masks or respirators. Several scenarios were explored, with the following results:

• when neither masks nor respirator s were used, the total percentage of the population infected was estimated at 75 percent (in a population of 1 million people);

• if 10 percent of the population wore surgical masks (assumed in this scenario to be 2 percent effective in reducing susceptibilityand infectivity), the total number of cases would be only minimally reduced (to approximately 73 percent);

• increasing the percentage of the population wearing surgicalmasks to 50 percent (assumed in this scenario to be 5 percent effective in reducing susceptibility an d infectivity) reduced the infected population to approximately 69 percent;

• if 10 percent of the population wore N95 respirators (assumed in this scenario to be 20 percent effective in reducing susceptibility and infectivity), the total number of cases would be reduced toUNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 51

approximately 55 percent (a re duction of approximately 19 percent from not wearing masks or respirators); and

• increasing the percentage of the population wearing N95 respirators to 50 percent (assumed in this scenario to be 50 percent effective in reducing susceptibility and infectivity) dropped the total number of cases drastically to approximately 0.1 percent.

The authors concluded that surgical masks were unlikely to impact the epidemic because of low effectiv eness at reducing the spread of influenza among susceptible and infected individuals, while N95 respirators could reduce the impact of the epid emic, though they could not reduce the

R 0 below 1. The authors acknowledge that the effectiveness of the interventions are time dependent and that delays in mask-use initiation can have strong effects on the findings. The results from the model suggest that healthcare personnel would benefit from widespread use of properly fitting N95 respirators among susceptible and infected individuals.

Community Studies of PPE Use

Several recent studies have looked at community use of PPE. Results

of these studies have been inconsis tent because of differences in study design, setting, intervention type, a nd ability to control for confounding factors. MacIntyre and colleagues (2009) conducted a study on the use of face masks in households in Australia during the winters of 2006 and2007. The participating 145 households included adults with known exposure to a child with fever and other respiratory symptoms. The households were randomized to one of thr ee arms of the trial: (1) surgical

masks that were to be worn when in the same room as the ill child; (2) P2 masks (equivalent to N95 respirators), also to be worn when in the same room; and (3) a control group with no masks used. Adherence to the use of masks was found to be low (less than 50 percent). Of those who used the masks, a reduction in the risk of acquiring a respiratory infection wasnoted in the range of 60 to 80 percent, and no differences were seen between surgical masks and P2 masks, but the study was underpowered to

determine differences between these two interventions. In addition, the authors noted that some adults may have already been in the incubation period for infection because enrollmen t occurred in conjunction with a

sick child visit to a healthcare fac ility. Thus, the mask intervention may52 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

have been applied too late in the course of illness transmission within the

household.Hand hygiene has been demonstrated to provide a reduction in respiratory infections in the community setting (Aiello et al., 2008), but therole of face masks in combination with hand hygiene (i.e., layered interventions) had not been studied in a controlled intervention trial until recently. Several recent randomized community intervention studies have attempted to compare face-mask use and hand hygiene or a combination of both interventions during seasonal influenza seasons. In one study, researchers randomized university r esidence halls housing 1,297 student participants to use of face masks, face masks with hand hygiene, or a control group for a 6-week period during the influenza season (Aiello et al., 2010). Significant reductions in influenza-like illnesses were seen in the group using face masks and hand hygiene as compared with the control group (reductions of 35 to 51 percent after adjusting for vaccination and other factors). Compliance data were difficult to ascertain, and the mild influenza season may have impa cted the results. This study provided some insights on primary prevention rather than secondary prevention of illness because the participants were asked to wear masks before influenza-like illness was observed on campus. Larson and colleagues (2010) conducted a study examining secondary transmission of influenza infection (i.e., other than the index case) by providing one of three interventi ons to urban households. The 509

households were randomized to receiv e one of the following: (1) education on the prevention and treatment of upper respiratory infections and influenza, (2) the same educational component plus alcohol-based hand sanitizer, or (3) the educational component plus hand sanitizer and face masks (Larson et al., 2010). Compliance with wearing the face masks was low; half of the households provi ded with face masks reported usingthe face masks when they had a household member with an influenzalike illness. In multivariate analyses no differences were observed in the

rate of infection. A study by Cowling and colleagues (2 009a) assessed several interventions in 259 households and used seco ndary transmission of laboratoryconfirmed influenza infection in family members as the outcome measure. Households were identified through household members presenting to outpatient clinics with influen za-like illness confirmed as influenza A or B by rapid testing. An education intervention was provided to the 134 households in the control group, hand hygiene supplies were provided to 136 households, and 137 households received face masks and hand hy-UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 53

giene supplies. Data for all the households in the study found that someone in the household developed confir med influenza in 19 percent of the households. A significant reduction in confirmed influenza was seen for households receiving an intervention within 36 hours of the onset of symptoms in the index patient; no differences were seen in a comparison of the hand hygiene and the hand hygiene plus face masks groups.Challenges in studies of interventions in the community setting include adherence, observations for co mpliance, and disentangling the contribution of layered interventions (i.e., face masks and hand hygiene together) when the effect estimate size between layered and non-layeredinterventions may be small. Moreover, in a light influenza season difficulties in identifying cases rapidly can impact the statistical power and effectiveness of the interventions, r espectively. Last, these types of studies are unable to provide insights on the modes of transmission of influenza because face masks may bloc k both droplet spray and direct contact inoculation from hands contaminated with influenza virus.

Clinical Studies of PPE Use by Healthcare Personnel

Although the benefits of vaccination are clear (Fiore et al., 2009; Treanor et al., 1999), much less is certain about what types of respiratory

PPE are needed or the value of face masks worn by healthcare personnel.

Few studies have been conducted of effective PPE interventions to reduce the transmission of influenza in hospitals or other healthcare facilities to guide policy makers seeking to ensure the health and safety of healthcare personnel. The relative valu e of face masks versus N95 respirators in preventing influenza transmission is especially debated, and

recent reviews have concluded that there are insufficient data for recommending effective PPE approaches for preventing influenza transmission (Cowling et al., 2010; Gralton and McLaws, 2010; Jefferson et al., 2010). The possible modes of transmission of influenza, the confounding variables that exist in testing alte rnative interventions, and the common issues inherent with study design (see Box 2-2) suggest the complexity of the problem facing both investigators and policy makers.

Several observational studies have looked at various aspects of PPE use, but usually in small numbers of healthcare personnel. Ng and colleagues (2009) performed a survey of 133 on-duty nurses, and then divided them into cases (nurses who contracted influenza-like illness during the study period) and compared them to nurses who did not. A54 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

significant difference was noted between cases and controls in use of PPE, specifically the use of gloves, gowns, and face shields. No mention was made of respiratory protection. A significant difference between the cases and controls was that cases were less likely to be vaccinated and were also more likely to have been exposed to a sick colleague without using PPE. In a survey of healthcare personnel participating in a medical mission and treating patients in crowde d conditions, fewer cases of acuterespiratory illness were noted for personnel using hand sanitizer; however, use of face masks was not reported to make a difference (Al-Asmary et al., 2007). A study of 32 healthcare personnel (in which one group

wore face masks and the other di d not) found no differences in occurrence of the common cold, but the smal l number of study participants did not allow for adequate exploration of the study question (Jacobs et al., 2009). A retrospective study compared “frontline” healthcare personnel confirmed to have SARS with those who did not acquire the disease (Chen et al., 2009b). The risk of contracting SARS increased for those who performed tracheal intubations of SARS patients and for those who cared for “super-spreader” SARS patie nts. Risk decreased for those healthcare personnel wearing multiple pairs of gloves and for those who avoided face-to-face contact with SARS patients. Observations during the 2009 H1N1 epidemic were reported from a Singapore hospital that documented th e varying requirements for respirators or face masks based on different departments of the hospital or work tasks during three phases of the 2009 H1N1 epidemic (Ang et al., 2010).

No difference was seen in the tran smission of H1N1 to healthcare personnel. Many healthcare personnel w ho were confirmed to have H1N1 had not cared for H1N1 patients and may have acquired the disease in community settings. This hospital ha d worked with cases of SARS in 2003, and the authors stated that adherence to PPE, although not documented, was usually strict. Recently, the first randomized trial assessing the value of face masks compared with N95 respirators in preventing influenza among healthcare personnel was published (Loeb et al., 2009). Among the 446 nurses from 8 tertiary care hospitals in Ontario who participated in the study, 225 were assigned to wear surgical masks (the brand used at their respective hospitals), and 221 were assigned to wear N95 respirators during the 2008–2009 winter influenza season. Study participants also wore gowns and gloves (as part of routine infection control practice) when caring for patients with febrile respiratory illnesses. Online questionnaires wereUNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 55

BOX 2-2 Confounding Issues for Understanding the Transmission of Influenza and Other Viral Respiratory Diseases

Confounding Variables in Testing Interventions

• Variability in types of and fit of mask or respirator

• Compliance with appropriate use of mask or respirator

• Measuring compliance of mask or respirator use

• Hand hygiene rates

• Levels of environmental contamination

• Duration and intensity of exposure to influenza

• Variations among patients regarding di spersal of infectious particles after cough, sneeze, normal talking

• Susceptibility of healthcare personnel (antibody titer, vaccine status)

• Community and home exposure to the virus

Issues with Study Design

• Avoiding bias

• Accounting for confounders

• Measuring all possible modes of transmission

• Study power

• Measuring infection accurately, including measuring severity (indirect measure of exposure to infecting dose)

used twice a week to assess symptoms of influenza. The primary outcome examined by the study was laboratory-confirmed influenza. Compliance with PPE use was determined through audits during several weeks in March and early April 2009 that were anticipated to be the peak

of the influenza season. If the unit had patients with influenza or a febrilerespiratory illness, auditors were sent to observe use of masks or respirators. The study stopped collecting data in late April 2009, with the reporting of novel H1N1 influenza A and the recommendation by the Ontario Ministry of Health and Long- Term Care that N95 respirators beused for caring for patients with febrile respiratory disease. Laboratoryconfirmed influenza was documented in 50 of the 225 nurses allocated to wear surgical masks (23.6 percent) and in 48 of the 221 nurses allocated to wear N95 respirators (22.9 percent). The authors concluded that the similar results between groups indicated that surgical masks were noninferior to N95 respirators. Study limitations noted by the authors included challenges in assessing compliance with PPE use; lack of measurement on rates of hand hygiene or gown and glove use; and the source of infectious exposure (hospital or community exposure) could not be ascer-56 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

tained. Several subsequent letters to the editor noted issues including that measures of exposure risk were miss ing and the value of triage procedures and the adherence to cough etiquette were not measured (Srinivasan and Perl, 2009), concer ns about study power (Clynes, 2010), and concerns about the lack of eye-shield protection among nurses in the study (Finkelstein et al., 2010). This study has pointed out the many challenges in assessing the effectiveness of respirators and face masks in preventing influenza transmission, incl uding the rates of correct use and fit of respirators and masks, the level of environmental contamination, the duration and intensity of exposur e, and the susceptibility of healthcare personnel to H1N1. Similar to the community intervention studies,this type of study cannot provide information on the modes of transmission of influenza in the clinical setting. In future studies, the severity of infection might be an important secondary endpoint of interest because it may reflect infectious dose. Moreover, it will be important to add higher levels of monitoring for compliance and assessment of close contacts (such as household members) to bette r identify sources of infection in these types of studies.

Use of Face Masks and Respirators as Source Control

Face masks and respirators have al so been used as source control, that is, placing a mask on patients w ith respiratory illnesses in clinics or emergency departments to reduce the potential for disease transmission to other patients, family members, or healthcare personnel. Johnson and colleagues (2009) studied nine patients with documented influenza and asked each to cough 5 times into a 90 mm diameter petri dish containing transport media. With no mask on, 7 of 9 patients had detectable virus. However, with either a surgical maskor N95 mask on, no virus was detected. The authors concluded that as a source control, masks were equally effective in preventing dissemination. Because this was not a study of transmission, however, one can only say that the concept of droplet spray dissemination being controlled with a surgical mask is plausible, but

unconfirmed.UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 57

SUMMARY OF PROGRESS

Animal studies have found that the ferret and guinea pig models appear to be highly representative of hu mans in terms of their susceptibility to infection, the influenza viral stra ins that display a transmissible phenotype, and the kinetics with which transmission occurs. Experiments performed in both of these animal models suggest that transmission of influenza viruses can proceed by both droplet spray as well as aerosol modes, which would include respirable particles. Animal studies have also pointed to a number of environmental factors, including relativehumidity and temperature that may influence transmission. Recent studies that have employed environmental monitoring of the air for influenza,

as well as others that have examined contamination of fomites and hands with H1N1, have provided insights on the potential for influenza-virus contamination of the healthcare environment. Nonetheless, data on the viability of influenza in air sample s and fomites in these settings are limited. Mathematical models have b een developed to better characterize the relative contribution of influenza transmission modes. Available,well-specified parameters for these models are limited because information is lacking on the viability of influenza in aerosols, salivary virus concentrations, amounts of virus in r espirable and inspirable particles, and the quantity and persistence of viability on various fomites in the healthcare setting. Taken together, progress has been made in understanding the modes of transmission, but the relative contributions of the

modes are still unclear. Mu ch remains to be learned about the effectiveness of control measures to prevent transmission.

Observational studies and controlled studies relevant to PPE use and transmission of influenza or other viral respiratory diseases are limited because study protocols were largely not in place for 2009 H1N1 or forrecent seasonal flu periods, and studies have not provided adequate power to answer questions regarding the effectiveness of using PPE in reducing or preventing disease transmission.

FINDINGS AND RESEARCH NEEDS

As discussed throughout this chapter, much remains to be learned about the transmission of influenza and other viral respiratory diseases. The committee’s overall findings in this area (Box 2-3) highlight the current limitations on data regarding tran smission that are needed to inform58 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

decisions on the protection of hea lthcare personnel and patients. The committee heard about a number of ongoing research efforts at its June 2010 workshop (Appendix A). Sustained efforts will be critical, as prior research efforts from the 1940s to 1990s have largely ebbed between pandemics. The committee has identified a range of research efforts, some of which can be addressed expeditiously (in the next 6 to 12 months) andhave a significant impact on improving the nation’s readiness for pandemic influenza; long-term studies ar e also needed to more fully understand disease transmission and prevention strategies. As in the 2008 IOM report, the recommendations focus on a comprehensive research strategy to address critical questions in as e xpedited and coordi nated manner as possible.

BOX 2-3 Findings

• Standardized terms, definitions, and appropriate classifications areneeded to properly describe transmission routes and aerodynamic diameter of particles associated with respiratory disease transmission.

• Influenza and other respiratory viruses differ in virulence and transmission routes.

• A comprehensive research strategy is needed. Transmission routes need to be better understood to select appropriate personal protective equipment (PPE) and better protect healthcare personnel and patients. An in-depth understanding of the re lative contribution of the transmission routes will require research at many levels, including basic science laboratory studies, monitoring st udies, environmental intervention studies, and clinical and community-based studies.

• To determine the risk of specific exposures and tasks, research should be done to characterize the aerodynam ic diameter of particles and concentration of influenza in aerosols generated by various procedures to enable a comparison of aerosol si zes and concentrations of influenza generated by coughing, sneezing, talking, and exhalation.

• The potential for confounding and comple xity in conducting intervention
studies of the effectiveness of PPE wi thin the clinical setting makes it impossible to determine various routes of transmission in this setting.Instead, clinical intervention and observational studies of PPE will continue to be useful in determining the effectiveness of disease prevention measures albeit without a complete understanding of the specific mechanisms and to garner information on the best precautionary measures for future outbreaks of influenza or other viral respiratory diseases.

• Little is known about the potential PPE role of face shields and face masks in preventing transmission of viral respiratory diseases.UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 59

Animal studies Although data in ferrets and guinea pigs indicatethat vaccination, antiviral treatment, and altered environmental conditions can each reduce or abrogate transmission, confirmatory and more in-depth experimentation would be va luable in determining which interventions are likely to be the most effective. In vivo studies on the impacts of increased air exchange and UV treatment of air would also be highly informative and relatively simple to execute in an animal model.

Environmental studies Future studies are needed to assess whether the identified influenza RNA in aerosol samplers (in multiple locations, e.g., schools, trains, healthcare facilities) are viable and reflect the extent to which individuals are exposed to aerosols of influenza within these environments. In addition, the impact of environmental factors, such asUV and humidity, on influenza transmission and infection should be examined in the community and healthcare setting. Modeling studies Statistical and mathematical models need to be evaluated for their utility in pr ediction and inferences regarding

the relative contributions of differe nt transmission modes in varying environmental/community contexts. Collaborations between experimental or observational research and mathematical modelers are warranted so that the parameters used in mathema tical models are based on rigorous data and provide evidence that w ould help narrow parameter estimates used in modeling.

Clinical studies Appropriately powered studies are needed that examine all possible modes of transmission, measure the rates of compliance with each intervention of interest, and define the pre-exposure influenza antibody titers of study subj ects. Environmental levels of contamination need to be studied, in cluding cultures from air sampling and swabs of hard surfaces. Serological studies of exposure to influenza virus in family members or roommates w ould be a reasonable marker of home exposure during the study period. Useful measures would also include the distribution of the size of respirat ory particles of patients exposed tothe healthcare personnel and some measure of the intensity of the exposure to patients that might include distance from, time in contact with, and specific procedures performed on the infected patients.

Studies on the role of PPE The potential role of face shields and face masks as PPE should be explored to determine the level of protection from droplet spray transmission. The role of fomites is unclear in the healthcare setting. Additional studies ar e needed to determine what role gowns, gloves, face masks, and respirators might play in influenza transmission. Further work on donning and doffing processes is also60 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

needed. Studies should examine whether antiviral-coated PPE provides any additional protection and how main tenance and reuse are affected.

RECOMMENDATIONS

Recommendation: Develop Standardized Terms and DefinitionsCDC and the Occupational Safety and Health Administration, in partnership with other relevant agencies and organizations, should work to develop standardized terms, definitions, and appropriate classifications to describe transmission routes and aerodynamic diameter of particles associated with viral respiratory disease transmission. This effort should

involve a consensus from the indu strial hygiene, infectious disease, and healthcare communities.

Recommendation: Develop and Implement a Comprehensive Research Strategy to Understan d Viral Respiratory Disease

Transmission The National Institutes of Health, in collaboration with other research agencies and organizations, should develop andfund a comprehensive research strategy to improve the understanding of viral respiratory disease transmission, including, but not limited to, examining the characteristics ofinfluenza transmission, animal models, human challenge studies, and intervention trials. This strategy should include

• an expedited mechanism for funding these types of

studies and

• clinical research centers of excellence for studying influenza and other respiratory virus transmission.

REFERENCES

Aiello, A. E., R. M. Coulborn, V. Perez, and E. L. Larson. 2008. Effect of handhygiene on infectious disease risk in the community setting: A metaanalysis. American Journal of Public Health 98(8):1372-1381. Aiello, A. E., G. F. Murray, V. Perez, R. M. Coulborn, B. M. Davis, M. Uddin, D. K. Shay, S. H. Waterman, and A. S. Monto. 2010. Mask use, hand hygiene, and seasonal influenza-like illness among young adults: AUNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 61

randomized intervention trial. Journal of Infectious Diseases 201(4):491-

498. Al-Asmary, S., A. S. Al-Shehri, A. Abou-Zeid, M. Abdel-Fattah, T. Hifnawy, and T. El-Said. 2007. Acute respirator y tract infections among Hajj medical mission personnel, Saudi Arabia. International Journal of Infectious

Diseases 11(3):268-272. Alford, R. H., J. A. Kasel, P. J. Gerone, and V. Knight. 1966. Human influenza resulting from aerosol inhalation. Proceedings of the Society for Experimental Biology and Medicine 122(3):800-804. Ali, M. J., C. Z. Teh, R. Jennings, a nd C. W. Potter. 1982. Transmissibility of

influenza viruses in hamsters. Archives of Virology 72(3):187-197. Andrewes, C. H., and R. E. Glover. 1941. Spread of infection from the respiratory tract of the ferret. I. Transmission of influenza A virus. British Journal of Experimental Pathology 22:91-97. Ang, B., B. F. Poh, M. K. Win, and A. Chow. 2010. Surgical masks for protection of health care personnel against pandemic novel swine-origin influenza A (H1N1)-2009: Results from an observational study. Clinical Infectious Diseases 50(7):1011-1014. Atkinson, M. P., and L. M. Wein. 2008. Quantifying the routes of transmission for pandemic influenza. Bulletin of Mathematical Biology 70(3):820-867. Baker, M. G., C. N. Thornley, C. Mills, S. Roberts, S. Perera, J. Peters, A. Kelso, I. Barr, and N. Wilson. 2010. Transmission of pandemic A/H1N1 2009 influenza on passenger aircraft: Retrospective cohort study. British

Medical Journal 340:c2424. Bellei, N., E. Carraro, A. H. S. Perosa, D. Benfica, and C. F. H. Granato. 2007. Influenza and rhinovirus infections among health-care workers. Respirology 12(1):100-103. Belser, J. A., O. Blixt, L. M. Chen, C. Pappas, T. R. Maines, N. Van Hoeven, R. Donis, J. Busch, R. McBride, J. C. Paulson, J. M. Katz, and T. M. Tumpey. 2008. Contemporary North American influenza H7 viruses possess human receptor specificity: Implicati ons for virus transmissibility. Proceedings of the National Academy of Sciences (U.S.A.) 105(21):7558-7563. Blachere, F. M., W. G. Lindsley, T. A. Pearce, S. E. Anderson, M. Fisher, R. Khakoo, B. J. Meade, O. Lander, S. Da vis, R. E. Thewlis, I. Celik, B. T. Chen, and D. H. Beezhold. 2009. Meas urement of airborne influenza virus in a hospital emergency department. Clinical Infectious Diseases 48(4):438-

440. Boone, S. A., and C. P. Gerba. 2007. Si gnificance of fomites in the spread of respiratory and enteric viral disease. Applied and Environmental Microbiology 73(6):1687-1696. Brankston, G., L. Gitterman, Z. Hirji, C. Lemieux, and M. Gardam. 2007. Transmission of influenza A in human beings. Lancet Infectious Diseases 7(4):257-265.62 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Brauer, F. 2009. Mathematical epidemiology is not an oxymoron. BMC Public

Health 9(Suppl. 1):S2. Bryant, P. A., M. Tebruegge, G. Papadakis, C. Clarke, P. Barnett, A. J. Daley, M. South, and N. Curtis. 2010. Clinical and microbiologic features associated with novel swine-origin influenza A pandemic 2009 (H1N1) virus in children: A prospective cohort study. Pediatric Infectious Disease

Journal 29(8):694-698. Carrat, F., E. Vergu, N. M. Ferguson, M. Lemaitre, S. Cauchemez, S. Leach,

and A. J. Valleron. 2008a. Time lines of infection and disease in human influenza: A review of volunteer challenge studies. American Journal of Epidemiology 167(7):775-785.

———. 2008b. Time lines of infection and disease in human influenza: A review of volunteer challenge studies. American Journal of Epidemiology 167(7):775-785. Casanova, L., W. A. Rutala, D. J. Weber, and M. D. Sobsey. 2010. Coronavirus survival on healthcare pers onal protective equipment. Infection Control and Hospital Epidemiology 31(5):560-561. Cauchemez, S., C. A. Donnelly, C. Reed, A. C. Ghani, C. Fraser, C. K. Kent, L. Finelli, and N. M. Ferguson. 2009. Household transmission of 2009 pandemic influenza A (H1N1) virus in the United States. New England Journal of Medicine 361(27):2619-2627. Chen, S. C., C. P. Chio, L. J. Jou, an d C. M. Liao. 2009a. Viral kinetics and exhaled droplet size affect indoor transmission dynamics of influenza

infection. Indoor Air 19(5):401-413. Chen, W. Q., W. H. Ling, C. Y. Lu, Y. T. Hao, Z. N. Lin, L. Ling, J. Huang, G. Li, and G. M. Yan. 2009b. Which preventive measures might protect health

care workers from SARS? BMC Public Health 9:81. Chen, Y.-C., S.-C. Chang, K.-S. Tsai, and F.-Y. Lin. 2008. Certainties and uncertainties facing emerging respiratory infectious diseases: Lessons from

SARS. Journal of the Formosan Medical Association 107(6):432-442. Clynes, N. 2010. Surgical masks vs. N95 respirators for preventing influenza. Journal of the American Medical Association 303(10):937-938; author reply 938-939. Couch, R. B., R. G. Douglas, Jr., D. S. Fedson, and J. A. Kasel. 1971. Correlated

studies of a recombinant influenza- virus vaccine. 3. Protection against experimental influenza in man. Journal of Infectious Diseases 124(5):473-

480. Couch, R. B., J. A. Kasel, J. L. Gerin, J. L. Schulman, and E. D. Kilbourne.1974. Induction of partial immunity to influenza by a neuraminidasespecific vaccine. Journal of Infectious Diseases 129(4):411-420. Cowling, B. J., K.-H. Chan, V. J. Fang, C. K. Y. Cheng, R. O. P. Fung, W. Wai, J. Sin, W. H. Seto, R. Yung, D. W. S. Chu, B. C. F. Chiu, P. W. Y. Lee, M. C. Chiu, H. C. Lee, T. M. Uyeki, P. M. Houck, J. S. M. Peiris, and G. M. Leung. 2009a. Facemasks and hand hygiene to prevent influenzaUNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 63

transmission in households: A cluster randomized trial. Annals of Internal

Medicine 151(7):437-446. Cowling, B. J., V. J. Fang, S. Riley, J. S. Malik Peiris, and G. M. Leung. 2009b.

Estimation of the serial interval of influenza. Epidemiology 20(3):344-347. Cowling, B. J., Y. Zhou, D. K. Ip, G. M. Leung, and A. E. Aiello. 2010. Face masks to prevent transmission of in fluenza virus: A systematic review. Epidemiology and Infection 138(4):449-456. Cunney, R. J., A. Bialachowski, D. Thor nley, F. M. Smaill, and R. A. Pennie.

2000. An outbreak of influenza A in a neonatal intensive care unit. Infection Control and Hospital Epidemiology 21(7):449-454. Douglas, R. G. 1975. Influenza in man. In The influenza viruses and influenza

, edited by E. Kilbourne. New York: Academic Press. Pp. 395-447. Drinka, P. J., P. Krause, M. Schilling, B. A. Miller, P. Shult, and S. Gravenstein. 1996. Report of an outbreak: Nursing home architecture and influenza-A

attack rates. Journal of the American Geriatrics Society 44(8):910-913. Drinka, P. J., P. Krause, L. Nest, and D. Tyndall. 2004. Report of an outbreak: Nursing home architecture and infl uenza-A attack rates: Update. Journal of the American Geriatrics Society 52(5):847-848. Fabian, P., J. J. McDevitt, W. H. DeHaan, R. O. P. Fung, B. J. Cowling, K. H. Chan, G. M. Leung, and D. K. Milton. 2008. Influenza virus in human exhaled breath: An observational study. PLoS ONE 3(7):e2691. Finkelstein, Y., T. Schechte r, and S. B. Freedman. 20 10. Surgical masks vs. N95 respirators for preventing influenza. Journal of the American Medical

Association 303(10):938; author reply 938-939. Fiore, A. E., C. B. Bridges, and N. J. Cox. 2009. Seasonal influenza vaccines. Current Topics in Microbiology and Immunology 333:43-82. Fowler, R. A., C. B. Guest, S. E. Lapinsky, W. J. Sibbald, M. Louie, P. Tang, A. E. Simor, and T. E. Stewart. 2004. Transmission of severe acute respiratory syndrome during intubation and mechanical ventilation. American Journal of Respiratory and Critical Care Medicine 169(11):1198-1202. Francis, T., and T. P. Magill. 1935. Immunological studies with the virus of

influenza. Journal of Experimental Medicine 62(4):505-516. Furuya, H. 2007. Risk of transmission of airborne infection during train

commute based on mathematical model. Environmental Health and

Preventive Medicine 12(2):78-83. Gao, Y., Y. Zhang, K. Shinya, G. Deng, Y. Jiang, Z. Li, Y. Guan, G. Tian, Y. Li, J. Shi, L. Liu, X. Zeng, Z. Bu, X. Xia, Y. Kawaoka, and H. Chen. 2009.

Identification of amino acids in HA an d PB2 critical for the transmission of

H5N1 avian influenza viruses in a mammalian host. PLoS Pathogens 5(12):e1000709. Goodman, A. 2009. Viral shedding prolonged in children with H1N1 flu, especially younger children. http://www.medscape.com/viewarticle/711619 (accessed December 8, 2010).64 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Gralton, J., and M. L. McLaws. 2010. Protecting healthcare workers from pandemic influenza: N9 5 or surgical masks? Critical Care Medicine 38(2):657-667. Gregg, M. B. 1980. The epidemiology of influenza in humans. Annals of the New York Academy of Sciences 353:45-53. Gwaltney, J. M., Jr., P. B. Moskalski, and J. O. Hendley. 1978. Hand-to-hand

transmission of rhinovirus colds. Annals of Internal Medicine 88(4):463-

467. Hall, C. B. 2007. The spread of infl uenza and other respiratory viruses: Complexities and conjectures. Clinical Infectious Diseases 45(3):353-359. Hall, C. B., R. G. Douglas, Jr., and J. M. Geiman. 1980. Possible transmission by fomites of respiratory syncytial virus. Journal of Infectious Diseases 141(1):98-102. Hall, C. B., R. G. Douglas, Jr., K. C. Schnabel, and J. M. Geiman. 1981. Infectivity of respiratory syncytial virus by various routes of inoculation. Infection and Immunity 33(3):779-783. Halloran, M. E., F. G. Hayden, Y. Yang, I. M. Longini, Jr., and A. S. Monto. 2007. Antiviral effects on influenza viral transmission and pathogenicity:

Observations from household-based trials. American Journal of Epidemiology 165(2):212-221. Han, K., X. Zhu, F. He, L. Liu, L. Zhang, H. Ma, X. Tang, T. Huang, G. Zeng, and B. P. Zhu. 2009. Lack of airborne transmission during outbreak of pandemic (H1N1) 2009 among tour group members, China, June 2009. Emerging Infectious Diseases 15(10):1578-1581. Harper, G. J. 1961. Airborne micro-organisms: Survival tests with four viruses. Journal of Hygiene (London) 59:479-486.

———. 1963. The influence of environmen t on the survival of airborne virus particles in the laboratory. Archiv für die Gesamte Virusforschung 13:64-71. Hayden, F. G., L. V. Gubareva, A. S. Mont o, T. C. Klein, M. J. Elliot, J. M. Hammond, S. J. Sharp, and M. J. Ossi. 2000. Inhaled zanamivir for the prevention of influenza in families. Zanamivir family study group. New England Journal of Medicine 343(18):1282-1289. Hayden, F. G., R. Belshe, C. Villanueva, R. Lanno, C. Hughes, I. Small, R. Dutkowski, P. Ward, and J. Carr. 2004. Management of influenza in households: A prospective, randomized comparison of oseltamivir treatment with or without postexposure prophylaxis. Journal of Infectious

Diseases 189(3):440-449. Hemmes, J. H., K. C. Winkler, and S. M. Kool. 1960. Virus survival as a seasonal factor in influenza and polimyelitis. Nature 188:430-431. Hendley, J. O., R. P. Wenzel, and J. M. Gwaltney, Jr. 1973. Transmission of rhinovirus colds by self-inoculation. New England Journal of Medicine 288(26):1361-1364.UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 65

Hsu, S. B., and Y. H. Hsieh. 2008. On the role of asymptomatic infection in transmission dynamics of infectious diseases. Bulletin of Mathematical Biology 70(1):134-155. IOM (Institute of Medicine). 2008. Preparing for an influenza pandemic: Personal protective equipmen t for healthcare workers . Washington, DC:

The National Academies Press. Itoh, Y., K. Shinya, M. Kiso, T. Watana be, Y. Sakoda, M. Hatta, Y. Muramoto, D. Tamura, Y. Sakai-Tagawa, T. Noda, S. Sakabe, M. Imai, Y. Hatta, S. Watanabe, C. Li, S. Yamada, K. Fujii, S. Murakami, H. Imai, S. Kakugawa, M. Ito, R. Takano, K. Iwatsuki-Horimoto, M. Shimojima, T. Horimoto, H. Goto, K. Takahashi, A. Makino, H. Ishigaki, M. Nakayama, M. Okamatsu, D. Warshauer, P. A. Shult, R. Saito, H. Suzuki, Y. Furuta, M. Yamashita, K. Mitamura, K. Nakano, M. Nakamura, R. Brockman-Schneider, H. Mitamura, M. Yamazaki, N. Sugaya, M. Suresh, M. Ozawa, G. Neumann, J. Gern, H. Kida, K. Ogasawara, and Y. Kawaoka. 2009. In vitro and in vivo characterization of new swine-origin H1N1 influenza viruses. Nature 460(7258):1021-1025. Jacobs, J. L., S. Ohde, O. Takahashi, Y. Tokuda, F. Omata, and T. Fukui. 2009. Use of surgical face masks to redu ce the incidence of the common cold among health care workers in Japan: A randomized controlled trial. American Journal of Infection Control 37(5):417-419. Jefferson, T., C. Del Mar, L. Dooley, E. Ferroni, L. A. Al-Ansary, G. A. Bawazeer, M. L. van Driel, S. Nair , R. Foxlee, and A. Rivetti. 2010. Physical interventions to interrupt or reduce the spread of respiratory

viruses. Cochrane Database of Systematic Reviews 1:CD006207. Johnson, D. F., J. D. Druce, C. Birch, and M. L. Grayson. 2009. A quantitative assessment of the efficacy of surgical and N95 masks to filter influenza virus in patients with acute influenza infection. Clinical Infectious Diseases 49(2):275-277. Kar-Purkayastha, I., C. Ingram, H. Maguire, and A. Roche. 2009. The importance of school and social activities in the transmission of influenza A(H1N1)v: England, April-June 2009. Euro Surveillance 14(33). Klontz, K. C., N. A. Hynes, R. A. Gunn, M. H. Wilder, M. W. Harmon, and A. P. Kendal. 1989. An outbreak of influenza A/Taiwan/1/86 (H1N1) infections at a naval base and its association with airplane travel. American Journal of Epidemiology 129(2):341-348. Larson, E. L., Y. H. Ferng, J. Wong-McLoughlin, S. Wang, M. Haber, and S. S. Morse. 2010. Impact of non-pharm aceutical interventions on URIs and influenza in crowded, urban households. Public Health Reports 125(2):178-

191. Lau, L. L., B. J. Cowling, V. J. Fang, K. H. Chan, E. H. Lau, M. Lipsitch, C. K. Cheng, P. M. Houck, T. M. Uyeki, J. S. Peiris, and G. M. Leung. 2010. Viral shedding and clinical illness in naturally acquired influenza virus

infections. Journal of Infectious Diseases 201(10):1509-1516.66 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Li, Y., P. Leung, L. Yao, Q. W. Song, and E. Newton. 2006. Antimicrobial effect of surgical masks coated with nanoparticles. Journal of Hospital Infection 62(1):58-63. Lindsley, W. G., F. M. Blachere, K. A. Davis, T. A. Pearce, M. A. Fisher, R. Khakoo, S. M. Davis, M. E. Rogers, R. E. Thewlis, J. A. Posada, J. B. Redrow, I. B. Celik, B. T. Chen, and D. H. Beezhold. 2010a. Distribution of airborne influenza virus and respiratory syncytial virus in an urgent care

medical clinic. Clinical Infectious Diseases 50(5):693-698. Lindsley, W. G., F. M. Blachere, R. E. Thewlis, A. Vishnu, K. A. Davis, G. Cao, J. E. Palmer, K. E. Clark, M. A. Fisher, R. Khakoo, and D. H. Beezhold. 2010b. Measurements of airborne influenza virus in aerosol particles from human coughs. PLoS ONE [Electronic Resource] 5(11):e15100. Loeb, M., A. McGeer, B. Henry, M. Ofner, D. Rose, T. Hlywka, J. Levie, J. McQueen, S. Smith, L. Moss, A. Smith, K. Green, and S. D. Walter. 2004. SARS among critical care nurses, Toronto. Emerging Infectious Diseases 10(2):251-255. Loeb, M., N. Dafoe, J. Mahony, M. John, A. Sarabia, V. Glavin, R. Webby, M. Smieja, D. J. D. Earn, S. Chong, A. Webb, and S. D. Walter. 2009. Surgical mask vs. N95 respirator for preventing influenza among health care workers

a randomized trial. Journal of the American Medical Association 302(17):1865-1871. Lowen, A., and P. Palese. 2009. Transmission of influenza virus in temperate zones is predominantly by aerosol, in the tropics by contact: A hypothesis. PLoS Currents Influenza 1:RRN1002. Lowen, A. C., S. Mubareka, T. M. Tump ey, A. Garcia-Sastre, and P. Palese. 2006. The guinea pig as a transmission model for human influenza viruses. Proceedings of the National Academy of Sciences (U.S.A.) 103(26):9988-

9992. Lowen, A. C., S. Mubareka, J. Steel, and P. Palese. 2007. Influenza virus transmission is dependent on relative humidity and temperature. PLoS Pathogens 3(10):1470-1476. Lowen, A. C., J. Steel, S. Mubareka, and P. Palese. 2008. High temperature (30 degrees C) blocks aerosol but not contact transmission of influenza virus. Journal of Virology 82(11):5650-5652. Lowen, A. C., J. Steel, S. Mubareka, E. Carnero, A. Garcia-Sastre, and P. Palese. 2009. Blocking interhost transmission of influenza virus by vaccination in the guinea pig model. Journal of Virology 83(7):2803-2818. Macias, A. E., A. de la Torre, S. Moreno -Espinosa, P. E. Leal, M. T. Bourlon, and G. M. Ruiz-Palacios. 2009. Controlling the novel A (H1N1) influenza virus: Don’t touch your face! Journal of Hospital Infection 73(3):280-281. MacIntyre, C. R., S. Cauchemez, D. E. Dwyer, H. Seale, P. Cheung, G. Browne, M. Fasher, J. Wood, Z. Gao, R. B ooy, and N. Ferguson. 2009. Face mask use and control of respiratory virus transmission in households. Emerging Infectious Diseases 15(2):233-241.UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 67

Maines, T. R., L. M. Chen, Y. Matsuoka, H. Chen, T. Rowe, J. Ortin, A. Falcon, T. H. Nguyen, Q. Mai le, E. R. Sedyaningsih, S. Harun, T. M. Tumpey, R. O. Donis, N. J. Cox, K. Subbar ao, and J. M. Katz. 2006. Lack of

transmission of H5N1 avian-human reas sortant influenza viruses in a ferret

model. Proceedings of the National Academy of Sciences (U.S.A.) 103(32):12121-12126. Maines, T. R., A. Jayaraman, J. A. Belser, D. A. Wadford, C. Pappas, H. Zeng, K. M. Gustin, M. B. Pearce, K. Viswanathan, Z. H. Shriver, R. Raman, N. J. Cox, R. Sasisekharan, J. M. Katz, and T. M. Tumpey. 2009. Transmission and pathogenesis of swine-origin 2009 A(H1N1) influenza viruses in ferrets

and mice. Science 325(5939):484-487. Mitchell, C. A., and L. F. Guerin. 1972. Influenza A of human, swine, equine and avian origin: Comparison of survival in aerosol form. Canadian Journal of Comparative Medicine 36(1):9-11. Mitchell, C. A., L. F. Guerin, and J. Robillard. 1968. Decay of influenza A viruses of human and avian origin. Canadian Journal of Comparative

Medicine 32(4):544-546. Monto, A. S., M. E. Pichichero, S. J. Blanckenberg, O. Ruuskanen, C. Cooper, D. M. Fleming, and C. Kerr. 2002. Zanamivir prophylaxis: An effective strategy for the prevention of influenza types A and B within households. Journal of Infectious Diseases 186(11):1582-1588. Morens, D. M., and V. M. Rash. 1995. Lessons from a nursing home outbreak of

influenza A. Infection Control and Hospital Epidemiology 16(5):275-280. Moser, M. R., T. R. Bender, H. S. Margolis, G. R. Noble, A. P. Kendal, and

D. G. Ritter. 1979. An outbreak of influenza aboard a commercial airliner. American Journal of Epidemiology 110(1):1-6. Mubareka, S., A. C. Lowen, J. Steel, A. L. Coates, A. Garcia-Sastre, and P.

Palese. 2009. Transmission of influenza virus via aerosols and fomites in the guinea pig model. Journal of Infectious Diseases 199(6):858-865. Munster, V. J., E. de Wit, J. M. A. van den Brand, S. Herfst, E. J. A. Schrauwen, T. M. Bestebroer, D. van de Vijver, C. A. Boucher, M. Koopmans, G. F. Rimmelzwaan, T. Kuiken, A. Osterhaus, and R. A. M. Fouchier. 2009. Pathogenesis and transmission of swine-origin 2009 A(H1N1) influenza

virus in ferrets. Science 325(5939):481-483. Ng, T. C., N. Lee, S. C. Hui, R. La i, and M. Ip. 2009. Preventing healthcare workers from acquiring influenza. Infection Control and Hospital Epidemiology 30(3):292-295. Nicas, M., and R. M. Jones. 2009. Relative contributions of four exposure pathways to influenza infection risk. Risk Analysis 29(9):1292-1303.Nicas, M., and G. Sun. 2006. An integrated model of infection risk in a healthcare environment. Risk Analysis 26(4):1085-1096. Ooi, P. L., F. Y. Lai, C. L. Low, R. Lin, C. Wong, M. Hibberd, and P. A. Tambyah. 2010. Clinical and molecular evidence for transmission of novel68 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

influenza A(H1N1/2009) on a commercial airplane. Archives of Internal

Medicine 170(10):913-915. Riquelme, A., M. Alvarez-Lobos, C. Pavez, P. Hasbun, J. Dabanch, C. Cofre, J. Jimenez, and M. Calvo. 2009. Gastrointestinal manifestations among chilean patients infected with novel influenza A (H1N1) 2009 virus. Gut 58(11):1567-1568. Schaffer, F. L., M. E. Soergel, and D. C. Straube. 1976. Survival of airborne influenza virus: Effects of propag ating host, relative humidity, and composition of spray fluids. Archives of Virology 51(4):263-273. Schulman, J. L. 1967. Experimental transmission of influenza virus infection in mice. IV. Relationship of transmissibility of different strains of virus and recovery of airborne virus in the environment of infector mice. Journal of Experimental Medicine 125(3):479-488.

———. 1968. The use of an animal mode l to study transmission of influenza

virus infection. American Journal of Public Health and the Nation’s Health 58(11):2092-2096. Schulman, J. L., and E. D. Kilbourne. 1962. Airborne transmission of influenza

virus infection in mice. Nature 195:1129-1130. Shaman, J., V. E. Pitzer, C. Viboud, B. T. Grenfell, and M. Lipsitch. 2010. Absolute humidity and the seasonal onset of influenza in the continental

United States. PLoS Biology 8(2):e1000316. Smith, W., C. H. Andrewes, and P. P. Laidlaw. 1933. A virus obstained from influenza patients. Lancet 8:66-68. Sorrell, E. M., H. Wan, Y. Araya, H. Song, and D. R. Perez. 2009. Minimal molecular constraints for respiratory droplet transmission of an avianhuman H9N2 influenza A virus. Proceedings of the National Academy of Sciences (U.S.A.) 106(18):7565-7570. Srinivasan, A., and T. M. Perl. 2009. Respiratory protection against influenza. Journal of the American Medical Association 302(17):1903-1904. Steel, J., A. C. Lowen, S. Mubareka, and P. Palese. 2009. Transmission of influenza virus in a mammalian host is increased by PB2 amino acids 627K

or 627E/701N. PLoS Pathogens 5(1):e1000252. Steel, J., P. Staeheli, S. Mubareka, A. Garcia-Sastre, P. Palese, and A. C. Lowen. 2010. Transmission of pandemic H1N1 influenza virus and impact of prior exposure to seasonal strains or interferon treatment. Journal of Virology 84(1):21-26. Tellier, R. 2009. Aerosol transmission of influenza A virus: A review of new

studies. Journal of the Royal Society Interface 6(Suppl. 6):S783-S790. Tracht, S. M., S. Y. Del Valle, and J. M. Hyman. 2010. Mathematical modeling

of the effectiveness of facemasks in re ducing the spread of novel influenza A (H1N1). PLoS ONE 5(2):e9018. Treanor, J. J., K. Kotloff, R. F. Betts, R. Belshe, F. Newman, D. Iacuzio, J. Wittes, and M. Bryant. 1999. Evaluati on of trivalent, live, cold-adapted (CAIV-T) and inactivated (TIV) influe nza vaccines in prevention of virusUNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 69

infection and illness following challenge of adults with wild-type influenza A (H1N1), A (H3N2), and B viruses. Vaccine 18(9-10):899-906. Tumpey, T. M., T. R. Maines, N. Van Hoeven, L. Glaser, A. Solorzano, C.Pappas, N. J. Cox, D. E. Swayne, P. Palese, J. M. Katz, and A. GarciaSastre. 2007. A two-amino acid change in the hemagglutinin of the 1918

influenza virus abolishes transmission. Science 315(5812):655-659.Van Hoeven, N., C. Pappas, J. A. Belser, T. R. Maines, H. Zeng, A. GarciaSastre, R. Sasisekharan, J. M. Katz , and T. M. Tumpey. 2009. Human HA and polymerase subunit PB2 proteins confer transmission of an avian influenza virus through the air. Proceedings of the National Academy of Sciences (U.S.A.) 106(9):3366-3371. Van-Tam, J. 2010. Update on influenza challenge studies in the UK.

Presentation at the Institute of Medi cine workshop on Current Research Issues—Personal Protective Equipment for Healthcare Work ers to Prevent Transmission of Pandemic Influenza and Other Viral Respiratory Infections, June 3, Washington, DC. http://iom.edu/~/media/Files/Activity%

20Files/PublicHealth/PPECurrentRe search/2010-JUN-3/Van%20Tam%20% 20Panel%201%20approved%20for%2 0web.pdf (accessed December 8, 2010). Wan, H., E. M. Sorrell, H. Song, M. J. Hossain, G. Ramirez-Nieto, I. Monne, J. Stevens, G. Cattoli, I. Capua, L. M. Chen, R. O. Donis, J. Busch, J. C. Paulson, C. Brockwell, R. Webby, J. Blanco, M. Q. Al-Natour, and D. R. Perez. 2008. Replication and transmission of H9N2 influenza viruses in ferrets: Evaluation of pandemic potential. PLoS ONE 3(8):e2923. Wang, H., Z. Feng, Y. Shu, H. Yu, L. Zhou, R. Zu, Y. Huai, J. Dong, C. Bao, L. Wen, H. Wang, P. Yang, W. Zhao, L. Dong, M. Zhou, Q. Liao, H. Yang, M. Wang, X. Lu, Z. Shi, W. Wang, L. Gu, F. Zhu, Q. Li, W. Yin, W. Yang, D. Li, T. M. Uyeki, and Y. Wang. 2008. Probable limited person-to-person transmission of highly pathogenic avian influenza A (H5N1) virus in China.

Lancet 371(9622):1427-1434. Weber, T. P., and N. I. Stilianakis. 2008. Inactivation of influenza A viruses in

the environment and modes of transmission: A critical review. Journal of Infection 57(5):361-373. Welliver, R., A. S. Monto, O. Carewi cz, E. Schatteman, M. Hassman, J. Hedrick, H. C. Jackson, L. Huson, P. Ward, and J. S. Oxford. 2001. Effectiveness of oseltamivir in preventing influenza in household contacts:

A randomized controlled trial. Journal of the American Medical Association 285(6):748-754. Wong, B. C., N. Lee, Y. Li, P. K. Chan, H. Qiu, Z. Luo, R. W. Lai, K. L. Ngai, D. S. Hui, K. W. Choi, and I. T. Yu. 2010. Possible role of aerosol transmission in a hospital outbreak of influenza. Clinical Infectious

Diseases 51(10):1176-1183.

## 3

Designing and Engineering Effective PPE

Understanding workplace hazards is critically important to ensuring that personal protective equipment ( PPE) is available to healthcare personnel facing an influenza pandemic or other hazardous working conditions. Research on the transmission and virulence of the influenza virus and other potential infectious agents (Chapter 2) will inform decisions on the design and engineering of healthcare PPE. As innovative approaches begin to address the PPE challenges of the healthcare workplace, further efforts are needed that focus on how to address the unique or varied issues that healthcare personnel face—easy communications with patients and families, PPE that can be changed or reused between different patients, PPE that is comfortable during long wear times, and PPE that does not interfere with work performance.Healthcare personnel are not alone in having job-specific PPE requirements. Firefighters need PPE that addresses high temperatures, construction workers on roofs and high-rise structures need protection from falls, and both have many other PPE require ments. Innovations in healthcare PPE are starting to be seen in the marketplace, but much more needs to be done to move the design of PPE from an industrial perspective toward the realities of the healthcare workplace. This chapter focuses on research on designing and engineering effective PPE. The chapter begins with a brief overview of the 2008 report, followed by a synopsis of research th at has been conducted in the past several years. The chapter conclud es with the committee’s thoughts on research gaps and immediate and long-term research directions.

7172 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

BACKGROUND AND CONTEXT

FROM THE 2008 REPORT

The 2008 Institute of Medicine (IOM) report provided the outline for a lifecycle approach to PPE and emphasized that, in addition to fit and filtration for respirators and functiona lity requirements for other types ofPPE, numerous other factors play a significant role in the design and development of healthcare PPE. These factors include issues involving visibility, comfort and wearability, durab ility, maintenance and reuse, aesthetics, and cost (Figure 3-1). In considering a framework for th e design and development of PPE,the 2008 committee addressed the three phases of the design and engineering process typically associated with a product’s lifecycle:

• Product cost

• Total lifecycle

cost

• Minimal environmental impact • Protect against

influenza virus

• Guard against

contact with

contaminated
fluids and

aerosols

• Easy to

decontaminate and discard disposable

elements

• Easy to clean and

replace parts in

reusable PPE • Variety of styles

and colors

• Customizable • Maintain biomechanical

efficiency and sense of touch

and feel

• Odor-free

• Hypoallergenic

• Accommodate wide range of

users (face and body profiles)

• Compatibility across various

elements of the PPE

ensemble and with other equipment (e.g., stethoscope)

• Non-startling to patients and

families

• Facilitates communication with

others (verbal, facial) • Comfortable—no skin irritation or pressure points

• Breathable—air • Prolonged use

without discomfort

permeable

• Moisture absorbent—

wickability

• Low bulk and weight

• Dimensional stability

• Easy to put on and

take off (don and doff) • Adequate wear life

• Strength—tear,

tensile, burst

• Abrasion resistance

• Corrosion

resistance

FIGURE 3-1 A structured approach to evid ence-based performance requirements for personal protective equipment (PPE). SOURCE: IOM (2008).DESIGNING AND ENGINEERING EFFECTIVE PPE 73

1. User requirements analysis: understanding the work hazards and barriers to PPE use;

2. Design realization: identifying the key characteristics (Figure3-1) and translating the evidence-based performance requirements into the specific design of the PPE component while making appropriate trade-offs among the factors that drive design,including degree of protection, comfort, and the cost of designing the specific PPE component to meet the regulatory requirements; and

3. Field use and evaluation: requiring that the new PPE be testedin the field in order to provide a realistic assessment of its performance and to identify unintended consequences of use.

Fit and filtration are the major functional issues in the design and engineering of respirators. Most resear ch has focused on filtration. National Institute for Occupational Safety and Health (NIOSH) ratings for respirators of 95, 99, or 100 percent filtration efficiency are based on the percentage of 0.3 μ m particles that do not penetrate the test filter (IOM,2008). Influenza viruses, with estimated sizes ranging from approximately 0.08 to 0.12 μ m (although droplets with the virus can vary widely in size), follow standard particle filtration theory, and therefore a number of types of filters are effective. Less is known about issues regarding inwardface seal leakage and other aspects of respirator fit. The 2008 report recommended research on a number of respirator issues, including decontamination and reuse methods, comfort and tolerability concerns, poweredair-purifying respirators (PAPRs) designed to meet the needs of healthcare personnel, and improved face seals.The 2008 report also addressed research for gowns, gloves, eye protection, face protection, and other type s of PPE that might be needed to protect workers from infectious disease. These types of barrier protectionare designed primarily to protect against droplet spray and contact transmission that might occur when particles are transferred to the respiratory mucosa or conjunctiva (of the eyes) of susceptible individuals within close range. Testing of gowns has focused primarily on liquid barrier performance and breathability of the fa bric, with four levels of liquid barrier performance defined by the A ssociation for the Advancement of Medical Instrumentation’s (AAMI’s) testing standard, AAMI PB70. The prior report emphasized the need to e xplore whether specific clinical situations require varying types of gowns or whether other specifications are needed, as well as issues regardi ng feasibility of reuse, interface with74 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

other types of PPE (especially gloves), and advances in materials technology, including repellant finishes (IOM, 2008). For protective eyewear, including transparent face shie lds, issues regarding the interface with respirators were found to be a critical need. In addition, product performance standards for eye protection need to be defined more clearly because they now focus on the thickness and impact resistance of eye protection but do not address issues rele vant to influenza transmission (IOM, 2008). Healthcare personnel’s use of glov es can serve several purposes in infection control—creating a barrier to direct contact with contaminated surfaces, preventing patient-to-patient contamination if gloves are changed between patients and prope r hand hygiene is performed, and increasing awareness of the potential for self-inoculation when glovedhands touch the mucosa of the mouth, nose, or eyes. Research needs regarding gloves that were identified in the 2008 report included better barrier protection as well as wearability and improved interfaces with gowns and other PPE. Adherence to hand hy giene and other infection control practices are also important in preventing disease transmission.The 2008 report provided a list of immediate opportunities and longterm research needs for improving the design and effectiveness of healthcare PPE. The report also provided a set of recommendations in this area, which can be briefly summarized as follows:

• Define evidence-based performance requirements for PPE.

• Adopt a systems approach to the design and development of

PPE.

• Increase research on the design and engineering of the next generation of PPE.

• Establish measures to assess and compare the effectiveness of

PPE.

UPDATE ON RECENT RESEARCH

Research efforts since the prior report have continued to address a range of design and engineering issues with the goal of improving the PPE available to healthcare personnel and others. The following section provides an overview of recent research efforts, beginning with the research focused on respirators and face masks.DESIGNING AND ENGINEERING EFFECTIVE PPE 75

Respirators and Face Masks: Fit and Filtration

The protection provided by a particular respirator is a function of both the filtration capabilities of the material and how well the device fits the wearer. Total inward leakage (TIL) is the combination of filtration, face seal leakage, and leakage through respirator components, such as the

exhalation valve.

Filtration

Several issues concerning filtration have been raised recently. First, the filtration efficiency of face mask s is a concern because they are not developed as filtration devices. Second, researchers have been concerned about the penetration of nanoparticles (which includes the size range of influenza and other viruses) through respirator filter media and whether current NIOSH respirator certification methods accurately account forthose particles. Third, shortages of respiratory protection may occur during a pandemic, so alternative filter materials and equipment have been investigated.

Filtration efficiency of face masks Two recent studies investigated the filtration efficiency of face masks. Oberg and Brosseau (2008) evaluated filtration performance of nine face masks (cup, flat, duckbill, one and two straps, ear loops, surgical, laser, and procedure). Filter efficiencies ranged from 0 to 84 percent for the late x sphere tests and 4 to 90 percent in the sodium chloride (NaCl) test s. Dental masks showed significantly higher penetration (6 to 75 percent fo r latex and 53 to 90 percent for salt) than hospital masks (0.02 to 0.7 per cent for latex and 4 to 37 percent forsalt). Only 1 of the hospital masks (mask H) had less than 5 percent penetration of the salt particles. Lee and colleagues (2008c) investigated theprotection factor of face masks and respirators with a challenge of particles representing bacterial and viral size ranges (aerodynamic size: 0.04 to 1.3 μm) and found that none of th e masks had protection factors > 10. The protection factors of the tested N95 respirators were an average of 8 to 12 times greater than those of masks. One previous study (Li et al., 2006) reported that face masks provided 95 percent filtration efficiency for potassium chloride. However, Br osseau and Harriman (2007) pointed out that the study did not use a standard method and that the authors did not fully describe the technique. None of the face masks tested by Oberg76 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

and Brosseau (2008) or Lee and colleagues (2008c) provided sufficient protection to be considered respirators. This is not surprising considering

the fact that face masks were not in tended to be respiratory protective equipment.

Penetration of small particles NIOSH certification tests for N95 respirators use an NaCl aerosol challenge with a 300 nm most penetrating particle size (MPPS). 1 However, many electret filter media that use electrostatic charge to capture particl es have an MPPS ranging from 30 to 100 nm (Shaffer and Rengasamy, 2009). Concerns have been raised regarding the filtration performance of N95 respirators against smallerviral- and bacterial-sized particles. Eninger and colleagues (2008b) reviewed the NIOSH aerosol particle-size distribution and measurement

method. The authors f ound that, although the salt aerosol does contain a significant fraction of ultrafine (diame ters < 100 nm) particles, the method and equipment used cannot accurately measure the contributions of particles below 100 nm. In fact, 68 percent by count and 8 percent by mass of salt particles below 100 nm did not si gnificantly contribute to the filter penetration measurement. Therefore, the existing NIOSH certification protocol may not adequately reflect the penetration of ultrafine particles. Several groups of researchers have investigated the filtration performance of respirators against nanoparticles. Eninger and colleagues (2008a) investigated the filtration pe rformance of one N95 and two N99 filtering facepiece respirators against one inert particle and three virus aerosols at flow rates of 30, 85, and 150 L/min. The respirators were sealed on a manikin. The most penetrating particle size for challenge aerosols was < 0.1 μm for all three respirators. Mean particle penetration, by count, was increased significantly wh en the size fraction of particles < 0.1 μm was included compared to particles > 0.1 μm. Penetration of the salt aerosol was greater than that of the tested biological aerosols, suggesting that inert aerosols can be used to assess filter penetration of

virions. Inhalation airflow rate had a significant effect on particle penetration. The authors suggested that furt her research is needed with cyclic flows with high peak inspiratory flows. A study of the filtration performan ce of five N95 and two P100 filtering facepiece respirators against monodisperse silver aerosol particles

1 The MPPS is the particle size that has the lowest filtration efficiency. Particles near the MPPS are too large to be efficiently captured by diffusion, but they are too small to be efficiently captured by the filtration mechanisms of impaction and interception.DESIGNING AND ENGINEERING EFFECTIVE PPE 77

in the 4 to 30 nm range at 85 L/min found that both types of respiratorsshowed a decrease in percentage of penetration, with a decrease in particle diameter down to 4 nm (Renga samy et al., 2008). This study supports prior studies that indicate that NIOSH-approved air-purifying respirators provided expected filtra tion protection against nanoparticles. A follow-up study using a polydisperse NaCl aerosol test with a 238 nm mass median aerodynamic diameter and two monodisperse aerosol tests concluded that the eight filtering facepiece respirator models tested met expected filtration performance against nanoparticles (Rengasamy et al., 2009). The NIOSH-certified respirators have a minimum efficiency of 95 percent for the N95 and 99.97 percent for the P100. The European Normrequires a minimum efficiency of 94 percent for a filtering facepiece respirator class P2 (FFP2) and 99 percent for a filtering facepiece respirator class P3 (FFP3). Penetrations from the polydisperse aerosol test were < 1 percent for the N95 and FFP2 models and < 0.03 percent for the P100

and FFP3 models.In a study by Eshbaugh and colleagues (2009), the researchers examined the effects of varying flow conditions on aerosol penetration forboth N95 and P100 filtering facepiece respirators and cartridges. Challenges were inert solids and oil aerosols with particle sizes in the range of 0.02 to 2.9 μm; three constant fl ow and four cyclic flow conditions

were used. Penetration increased unde r increasing constant- and cyclicflow conditions. The MPPS for the P 100 filters was 50 to 200 nm and 50 nm for N95 filters. Shaffer and Rengasamy (2009) reviewed research published since 2000 on respirator filtration and leakage data for nanoparticles. The MPPS was in the 30 to 100 nm range and was impacted by the filter media and test conditions, particularly flow rate. They found that filtration of monodisperse nanoparticles at the MPPS varied from 1.4 to 10 percent for the N95 filtering f acepiece respirator. They identified the greatest need for further research as human laboratory or workplace protection factor studies to measure TI L for respirators used for protection against nanoparticles. Wander a nd Heimbuch (2009) tested one N95 and one P100 filtering facepiece respirator with aerosolized particles (count mode diameter ~0.8 μm) of H1N1 and inert beads at 85 L/min using the Laboratory-Scale Aerosol Tunnel. The N95 removed > 99 percent of viable H1N1 while the P100 removed > 99.99 percent. They performed the same against the inert beads. The authors concluded that infectious microorganisms and inert pa rticles of the same size have the same impact on the filtering efficiency of filtering facepiece respirators.78 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Although these studies used different challenge aerosols and different test methods, several common results emerge. Inhalation airflow rate had a significant effect on particle penetration (Eninger et al., 2008a; Eshbaugh et al., 2009). NIOSH- or European Norm–certified filtering facepiece respirators achieved expected filtration performance when challenged with nanopar ticle aerosols (Eninger et al., 2008a; Eshbaugh et al., 2009; Rengasamy et al., 2008, 2009). The MPPS is below 100 nm for most electret filter media (Eninger et al., 2008a; Eshbaugh et al., 2009; Rengasamy et al., 2009), though one researcher (Eshbaugh et al., 2009)reported 200 nm for two models of filtering facepiece respirators. Finally, inert particles have penetration performance similar to virus particles (Eninger et al., 2008a; Wander and Heimbuch, 2009).

Alternative filter materials In the event of a pandemic, there may not be enough respirators available to meet demand. Rengasamy and colleagues (2010a) examined the filtration performance of common cloth materials, such as sweatshirts, T-shirts, towels, scarves, and cloth masks, against nanoparticles using polydisperse and monodisperse aerosols (20 to 1,000 nm) at two face velocities. The cloth materials had penetration levels of 40 to 90 percent for polydisp ersed NaCl, well above that of N95 respirators. Penetrations of 9 to 98 percent were obtained for differentmonodisperse NaCl aerosol nanoparticles. These materials had penetration levels similar to some face masks that were tested previously. They concluded that only minimal protec tion would be provided by wearing masks made out of these cloth materials, especially when considering that face seal leakage will decrease protection further.

Fit

Face seal leakage is a critical factor in the amount of protection provided by a respirator. Although much research has been done on filtering media and improving filter efficiency, the fit side of the equation has not been explored in such depth. Seve ral recent studies examined aspects of fit related to healthcare personnel.

Face masks Two recent studies examined the extent to which face masks fit the face. Duling and colleagues (2007) assessed six face masks. The simulated workplace protection factor fifth percentile value was 1.4 and the lower 90 percent confidence limit was 1.2, indicating that none of theDESIGNING AND ENGINEERING EFFECTIVE PPE 79

masks provided adequate protection. Oberg and Brosseau (2008) evaluated facial fit of 5 face masks usi ng qualitative and quantitative fit tests with 20 human volunteers. When the subjects put on the face masksthemselves, they all failed the qualitative fit test. When they were assisted with donning the face masks, 18 subjects failed the fit test. For unassisted donning, average quantitative fit factors were 2.5 to 6.9; for assisted donning, they ranged from 2.8 to 9.6. None of the masks testedattained an individual fit factor of 100, the minimum passing level required by the Occupational Safety and Health Administration (OSHA) for a half-mask filtering facepiece respirator.

Loose-fitting PAPRs Loose-fitting PAPRs may be worn by healthcare personnel who have beards or who cann ot otherwise wear an N95 filteringfacepiece or elastomeric air-purifying respirator. The unfiltered, exhaled air from the PAPR may transmit virus from the wearer to others. An N95 respirator may be worn inside the PAPR to prevent this from happening. Roberge and colleagues (2008) used a manikin to assess the protection factor of a loose-fitting PAPR with and without an N95 respirator gluedto the manikin. Flow rates were 25 L/min and 40 L/min. The N95 significantly increased the PAPR protection factor even when the PAPR blower was turned off. However, cons ideration should be given to thepossible negative impact of the additional physiological burden of wearing an N95 respirator inside a PAPR (Roberge, 2008). Additionally, their results might not hold in the work setting because the N95 was glued to the face (Roberge et al., 2008). Some loose-fitting PAPRs do not fully encapsulate the head, making it possible for the wearer to overbreathe the blower and possibly be exposed to contaminants (Roberge et al., 2008). Johnson and colleagues (2008) found that the 1.1 L of air inside theloose-fitting PAPR they tested would act as a buffer against contaminated air that leaks into the respir ator due to overbreathing the blower. That volume could also help if an N95 were worn under the PAPR and

face seal leaks occurred.

Fit testing and inward leakage Several large-scale fit tests of healthcare personnel were completed recen tly (Lee et al., 2008b; McMahon et al., 2008; Oestenstad et al., 2007; Wilkinson et al., 2010; Winter et al., 2010). McMahon and colleagues (2008) found that 5 percent of men and 15 percent of women could not pass the fit test with the first respirator tried, while Lee and colleagues ( 2008b) had 26 percent of workers fail the fit test with the first respirator. Winter and colleagues (2010) found80 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

that 28 percent of 50 staff members did not fit the 3 respirators tested. Wilkinson and colleagues (2010) found that 82.9 percent of 6,160 healthcare personnel were successfully fitted with the first respirator, 12.3 percent required testing with a second respirator, and 4.8 percentrequired testing with 3 or more respirators. Therefore, multiple respirators are likely to be needed to get p assing fit tests for all staff. First-time pass rates may improve after NIOSH incorporates the new sizing panels (Zhuang et al., 2007, 2008) into its TIL certification requirement. Gender and age in women may be significant factors in achieving a successful fit (McMahon et al., 2008), though Oestenstad and colleagues (2007) did not find a gender difference in the 41 subjects they tested. Gender, respirator brand, and test repetition did not have any significant effects on location or shape of leaks assessed on half-mask respirators using a fluorescent tracer during fit tests (Oestenstad and Bartolucci, 2010). There was a difference in fit test leak-site distribution for women, and the authors suggested that facial dimensions may be an importantfactor. In fact, their prior research showed that fit was significantly associated with face length and lip width and possibly face width (Oestenstad et al., 2007). Weight gain during pregnancy may impact fit due to changes in facial anthropometric s (Roberge, 2009). Wilkinson and colleagues (2010) found that personnel who reported their race as Asian had the highest failure rate and that r ace was correlated with facial shape. Training improved the fit test pass rate (Lee et al., 2008b; Winter et al., 2010). However, as time elapsed from th e fit test, pass rates were similarto those prior to training, although frequent use after training led to increased pass rates (Lee et al., 2008b). Experience of the fit testers was found to be a significant factor in achieving a successful fit test with the first respirator tried (Wilkinson et al., 2010). Their testers selected a resp irator based on observations of the subject’s facial characteristics, the physical fit of the respirator, and the “real-time” option on the PortaCount ® fit tester. Janssen and colleagues (2007) evaluated the workplace protection factor of an N95 filtering facepiece respirator during light, modera te, and heavy intensity tasks in asteel foundry and found a large variability in protection because of removing and re-donning the respirator. This may also be a problem in healthcare settings. They suggested that a time-weighted, average workplace protection factor be consid ered to estimate ongoing protection.Participants at a NIOSH-sponsored workshop (Brosseau, 2009) expressed interest in developing a respirator that did not require initial and annual fit tests and provided sugges tions for improving the fit capabili-DESIGNING AND ENGINEERING EFFECTIVE PPE 81

ties of respirators. Au and colleagues (2010) proposed using a customizable, reusable mask with high-efficien cy air filters. They investigated the efficacy of this mask without fit testing versus a fit tested N95 respirator in 22 volunteers. The median filtration factor was significantly higher for the N95 respirators compared to the ma sk that is cut to size. Only 16 of the 22 volunteers had a fit factor great er than 100. This was lower than the pass rate for the N95 (19/22), but was not significantly different. The

authors concluded that the customizab le mask should be studied further, but that it should not be used without fit testing at this time. Face seal leakage is an important factor in respirator protection, and it depends on several factors, including proper respirator selection, fit, and donning. Cho and colleagues (2010) found that most particle penetration occurs through face seal leak age even when the respirator fits well (workplace protection factor = 515), and that particle penetration of the face seal decreases with increases in breathing rate and particle size. Similarly, Grinshpun and colleagues (2009) found that the number of particles penetrating through the facepiece seal far exceeded penetration through the filter medium for both an N95 respirator and a face mask using challenge particles in the 0.03 to 1 μm range. Lee and colleagues (2008c) investigated the protection factor of four N95 respirators and three face masks with a challenge of particles representing bacterial and viral size ranges (aerodynamic size: 0.04 to 1.3 μm). Prior research (Coffey et al., 2004) had demonstratedhigh protection levels for Respirator A and medium protection for Respirator B. Respirators C and D were the same except D had an exhalation valve. Overall, 29 percent of N95 respirators and 100 percent of face masks had protection factors of < 10,the assigned protection factor for the N95 (Lee et al., 2008c). The percentages of N95 respirators with protection factors of > 10 for all particlesizes tested were 86, 36, 89, and 78 percent for Respirators A to D, respectively. There were no significant differences in the protection factor

between the N95 and N95 with the ex halation valve. The protection factors of the N95 were an average of 8 to 12 times greater than those of

face masks.Particle size–dependent face seal leakage has not been fully investigated (Shaffer and Rengasamy, 2009) . However, NIOSH has initiated

studies to determine whether face seal leakage of nanoparticles is consistent with the leakages observed for gases/vapors and larger particles.Further research on leakage of nanoparticles is important to better understand the effectiveness of filtering facepiece respirators in workplaces where nanoparticles are present.82 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Preventing a Patient from Spreading Virus

One suggestion for protecting pers onnel from virus exposure is toplace a face mask or N95 respirator on a patient with confirmed influenza. Huang and Huang (2007) demonstrated greater bacterial leakage at close range for a face mask (15.8 percent of no mask control) than for anN95 respirator (4.1 percent of control). Placing positively charged polypropylene edging on the mask and re spirator decreased leakage to 4.5 and 1.8 percent of control, respectively. This indicates that masks and respirators could be modified easily to decrease virus transfer.Tang and colleagues (2009) used a schlieren optical method to visualize cough flows of volunteers wearing either a face mask or N95 respirator. With the N95, more of the cough went through the front of the respirator compared to the face mask , and the N95 was better at preventing leakage of the cough. The face mask on the standing people who coughed blocked the forward motion ofthe cough jet and directed it upward, downward, and out of the sid es of the mask. The leakage air from both the mask and respirator had little momentum. They concluded thatboth face masks and N95 respirators decelerated and redirected the expelled air, which then joined the ge neral upward motion of the cougher’sthermal plume created by body heat. This prevented the cough from being projected forward as a rapid turbulent jet over distances sufficient to reach the breathing zones of other individuals. Diaz and Smaldone (2010) recently developed a headform-based system to evaluate the effectiveness of N95 respirators and loose- or tight-fitting face masks in preventing tr ansmission of infectious aerosolsfrom a source to a receiver. Although an N95 on the source filtered significantly more particles than the face masks, the simulated workplaceprotection factor did not differ for the unmasked receiver. When the receiver wore each mask or respirator, < 1 percent of the particles were filtered and the simulated workplace protection factor was 1.4 to 2.2. Sealing an N95 to the source using Vaseline ® yielded a simulated workplace protection factor of 4,082, and sealing it to the receiver resulted in a protection factor of 118. The authors concluded that the face masks worn at the source resulted in greater protection than a face mask or respirator worn on the receiver. Both Huang and Huang (2007) and Tang and colleagues (2009) showed greater leakage with the face mask than with the N95 respirator. This seems to contrast with the results of Johnson and colleagues (2009), who showed that both fully blocke d virus expulsion. However, HuangDESIGNING AND ENGINEERING EFFECTIVE PPE 83

and Huang as well as Tang and colleagues considered leakage from the sides of the face mask and respirator, while Johnson and colleagues had volunteers cough directly onto the collection plate. Although Tang and colleagues (2009) indicated that the cough flow was directed away from the receiver, they did not assess filtration, so virus particles that could not be observed with the schlieren opti cs could have reached the receiver. Diaz and Smaldone (2010) did not use heated manikins, so there were no thermal plumes that may have directed the particle flow upward and away from the receiver. More resear ch is needed to understand the particle dynamics of exhaled viruses while wearing a face mask or respirator

in order to make a recommendation re garding patient mask or respirator

wear.

Summary: Respirator and Face Masks—Fit and Filtration

Several studies have shown that face masks do not have sufficient filtration or fit to provide adequate inhalation protection of small particles to wearers. NIOSH-certified N95 respirators have been shown by several studies to provide expected filtration levels of nanoparticles. However, high filtration efficiency al one does not ensure that the wearer will be protected. Mask D in Oberg and Brosseau’s study (2008) had the second highest filtration efficiency, but the lowest fit factor. Because face seal leakage far exceeds penetrat ion through the filter (Cho et al., 2010; Grinshpun et al., 2009), future research should focus on improving respirator fit.Although Lee and colleagues (2008c) showed that some N95 respirators may not achieve an assigned protection factor of 10 when nanoparticles are present, whether higher fit factors would have been achieved with a different model resp irator is unknown. The rates of failure from their study were similar to the fit-factor failure rates of largescale protection-factor tests performed on healthcare personnel (Lee etal., 2008b; McMahon et al., 2008; Winter et al., 2010). Multiple respirators should be available for healthcar e personnel, as currently required by OSHA’s respirator standard, because it is unlikely that one model or size will fit all employees. Long-term storage of these additional respirators should have little impact on penetratio n levels (Viscusi et al., 2009a). Participants in a no-fit respirator workshop (Brosseau, 2009) identified

the need for a user seal check that wo rks, continuous fit checking rather than a no-fit test, and a respirator that can be put on easily multiple times.84 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

These features would be beneficial because protection varies with repeated donning (Janssen et al., 2007).

Respirators: Decontamination

Reuse of filtering facepiece respirat ors has been suggested as a strategy to counteract anticipated suppl y shortages during a pandemic and to reduce costs. The potential for the respir ator to serve as a fomite is a serious concern. Safe, effective dec ontamination methods that inactivatethe virus without altering the respirator performance and physical characteristics are necessary for this to occur. Respirators impregnated with antiviral particles may decrease the risk of virus transmission because of improper handling of virus-exposed pr otective equipment. To study this issue, methods are first needed to effectively deposit virus onto respirators, and then their potential to act as fomites can be investigated. Finally, the effectiveness of treated filter media and decontamination methods

can be assessed.To assess the efficacy of decontamination methods, reliable and repeatable methods of applying contam inant aerosols to filter media are needed. NIOSH has developed two systems for applying virus aerosols to respirator filter media that pass the aerosol through the filter media rather than depositing it on the surface. The bioaerosol respirator testsystem (Fisher et al., 2009) loads filter media with virus-containing particles while the droplet-phase aerosol respirator test system (Vo et al.,2009) applies droplets onto media. Another system, the Dry Aerosol Deposition Device (Heimbuch et al., 2009), deposits biological aerosols onto the surface using impaction, a system that allows the aerosol to be delivered quickly and with reproducible loading. Additionally, to assess the number ofviable particles on PPE, recovery methods are needed that allow removal without killing the virus. Casanova and colleagues (2009) devel oped a new technique for recovering bacteriophage MS2, a non-enveloped virus, from contaminatedgloves, gowns, respirators, and goggles. Recovered viruses were not inactivated, indicating that this technique can be used for viral survival

studies. Rate and length of virus survival are key facts needed to assess the potential for respirators to serve as fomites. Rengasamy and colleagues (2010b) applied MS2 as both an aerosol and as liquid drops onto N95 filter coupons. They demonstrated th at > 10 percent of the challengeDESIGNING AND ENGINEERING EFFECTIVE PPE 85

MS2 bacteriophage survived for 20 hou rs at 22°C and 30 percent relativehumidity. Fisher and Shaffer (2010) subsequently assessed MS2 survivability at 1, 2, 3, 4, 5, and 10 days. The authors found that 10 percent of initial MS2 survived for 4 days for both deposition methods, and that all samples had detectable levels of MS2 on the tenth day. Because MS2 is a non-enveloped virus, enveloped infl uenza virus survivability cannot be estimated from the current study. MS2 survives for longer periods of

time on surfaces than influenza does. Because fomites may be a source for indirect contact transmission, decontamination may be required before reuse.

Decontamination Methods

Studies of various types of decontamination methods have not yet been successful in identifying an e ffective means for decontamination that does not affect the structure and integrity of the respirator. Viscusi and coworkers (2007, 2009b) assessed th e effect of decontamination methods on filter aerosol penetration, physical appearance, and airflow resistance. From their initial list of 10 po tential decontamination methods (autoclave, isopropyl alcohol, bleach, hydrogen peroxide, microwave, soap and water, ultraviolet [UV] radiati on, dry heat, vaporized hydrogen peroxide, and ethylene oxide) (2007), li quid hydrogen peroxide, vaporized hydrogen peroxide, and UV radiation caused the least change in filterperformance. The authors (2009b) then further evaluated five decontamination methods (UV germicidal irra diation, ethylene oxide, vaporized hydrogen peroxide, microwave oven irradiation, and bleach) on threemodels each of N95, P100, and surgical N95 filtering facepiece respirators. Ethylene oxide and UV germicid al irradiation were the only methods that did not cause any observable ph ysical changes to the respirators. The bleach method left a noticeable odor, even after overnight drying, and bleach off-gassed when the decont aminated respirators were rehydrated with deionized water. UV germ icidal irradiation, ethylene oxide, and vaporized hydrogen peroxide were the most promising decontamination methods, although there are con cerns regarding throughput for the

latter two methods.Fisher and colleagues (2009) investigated a process for applying viral droplets to respirators to evalua te decontamination methods. Two decontamination methods, one physical (steam) and one chemical (bleach), were examined as well as two concentrations of organic matter (protec-86 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

tive factor) in the aerosol medium. The organic matter had a protein concentration similar to the organic challenge in ASTM E1053-97, Standard Test Method for Efficacy of VirucidalAgents Intended for Inanimate Environmental Surfaces . The organic matter may protect the virus by neutralizing the decontamination solution or by providing a physical barrier

to the decontaminant. Detectable di fferences were noted in the efficacy of the bleach decontamination, depending on the concentration of bleach and protective factor. Steam showed an effect for treatment time, but not protective factor. Viruses recovered were more likely to be found on the outer layer than when low concentrat ions of organic matter were used. This would be important for a dec ontamination method such as UV light that only reaches the outer layer of filter material. A study of bleach and UV radiation (Vo et al., 2009) found that bleach concentration and UV exposure time were factors in decontamination. UV radiation was recommended for further study, such as assessing the impact of pleats or folds in filtering facepiece respirators, because

it was non-toxic and did not leave an odor. Low-dose UV radiation resulted in 3-log 10 reductions in MS2, while higher doses resulted in no

detectable MS2. The authors discussed that further research is neededbecause non-enveloped MS2 may not behave in the same manner as enveloped viruses, and because the composition and size of particles used might not exactly mimic respiratory secretions. Finally, Salter and colleagues (2010) assessed the amount of residualchemicals on six models of filtering facepiece respirators after seven decontamination methods: ethylene oxi de, vaporized hydrogen peroxide, UV light, and four liquids (hydrogen peroxide, bleach, mixed oxidants,and dimethyl dioxirane). Six of the seven methods did not deposit significant amounts of toxic residue. The ethylene oxide–treated respirators had detectable levels of 2-hydroxyethyl acetate, a hazardous byproduct that may have been formed when th e ethylene oxide reacted with rubberparts of the respirator. As noted by other authors, bleach-treated respirators had a bleach odor after treatment. The bleach also corroded metal parts and discolored others. Dimethyl dioxirane and mixed oxidants also oxidized metal parts and had distinct odors.

Practical decontamination methods are needed as decontamination of filtering facepiece respirators is not currently an option. Although bleach is readily available and inexpensive, it has been shown to cause offensive odors and can cause corrosion. Ethylene oxide may react with rubber straps to create a hazardous bypr oduct. It also has problems with throughput, as does vaporized hydrogen peroxide. Other techniques suchDESIGNING AND ENGINEERING EFFECTIVE PPE 87

as soap and water, isopropyl alcohol, and microwaving can cause changes to the physical characteristics of the respirator. UV radiation shows promise, although its effectiven ess on inner filter layers and pleats is unknown, as is its affect on electrost atic properties of electret filters. Additional research with enveloped influenza viruses is needed.

Treated Filter Media

Several studies investigated the decontamination efficacy of treated filter media. Oxford and colleagues (2007) found that masks impregnated with QR-435, a green tea extract mix, trapped a significantly greater amount of virus compared to an untreated mask. Lee and colleagues (2008a) exposed iodine-treated filter media to aerosolized bacteria at an equivalent of 85 L/min flow. Viability of collected spores from controland treated media were assessed. Survival fraction was significantly lower for the treated filter versus untreated at room temperature and low relative humidity. However, there were no differences in viability at room temperature and high relative humidity or at high temperature and high relative humidity. Lee and colleagues (2009) then investigated theefficacy of iodine-treated filter media against MS2 aerosols. Treated media showed significantly higher viable removal efficiencies than untreated. Rengasamy and colleagues (2010b) applied MS2 virus droplet nuclei onto four coupons from antimicrobial respirators and controls.Antimicrobial agents included iodine, embedded silver-copper throughout the fibers of the outer layer of the mask, EnvizO3-Shield technology on the outer layer, and titanium dioxi de–coated filter layers beneath the outer layer. MS2 is less sensitive to many antimicrobial agents because it is a non-enveloped virus, which is hardier and able to survive longer than enveloped viruses such as influenza. The iodinated fibers from Respirator C had a significant increase in the log 10 reduction of MS2 at 37°C and 80 percent relative humidity, but not at lower temperatures and relative humidity. MS2 droplet nuclei survived for more than 20 hours at room temperature and 30 percent relative humidity. For an antimicrobial agent to be effective, it needs to reduce viability faster. At 22°C, 30 percent relative humidity, all four antimicrobial respirators had < 1 log 10 reduction, which was not significantly different from the control. The iodinated respirator showed 3.7 log 10 reduction of MS2 at 4 hours. This wassignificantly higher than the control, while the others were not significantly different from the control. Ther efore, the decontamination efficacy88 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

of the antimicrobial respirators de pends on storage conditions and theantimicrobial agent. Iodine from the filter that enters the extraction medium may also inactivate virus. Borkow and colleagues (2010) investigated the antiviral properties ofa copper oxide–containing N95 respirator. Treated and control respirators were exposed to aerosolized hum an influenza A virus and avian influenza virus at a constant airflow rate for 1 minute. The number of

infectious virus titers recovered from the masks was measured 30 minutes after exposure. The researchers found that the copper oxide particlesdid not impact filtration efficiency, but there was a statistically significant difference in retrieved infectious influenza between the control and copper oxide–impregnated masks. This could offer the possibility of reducing the risk of hand or environm ental contamination, with potential subsequent infection due to improper handling of exposed respirators.

Summary: Decontamination

Various techniques have been developed for applying viruses to respirators. Recent research has shown that non-enveloped viruses can persist on respirators for up to 10 days in hospital-like environments (Fisher and Shaffer, 2010). Although enveloped viruses such as the influenza virus may not survive as long, it is reasonable to assume that the virus will survive long enough to render the respirator a potential fomite. Current decontamination research has not demonstrated an effective technique for killing viruses that does not also have a detrimental impact on respirator physical characteristics or function. More research in this area

is needed. Iodine-treated and c opper oxide–impregnated filter media show promise for inactivating virus in the respirator.

Respirators: Tolerance, Physiological Responses,

and Communications

Respirators worn by healthcare pe rsonnel have the potential to impact comfort, physiological responses, task performance, and communications with each other and with patie nts. Protective equipment, such as respirators or face shields, may cr eate pressure points that cause discomfort. The breathing resistance and dead volume of the respirators may alter respiration and lead to a bu ild-up of carbon dioxide. Because respi-DESIGNING AND ENGINEERING EFFECTIVE PPE 89

rators may alter the wearer’s field of view, some tasks may be more difficult to perform and thus may take longer. The respirator covers themouth, muffling speech and removing visual cues for the listener. Additionally, the noise created by a PAPR blower and environmental noise

both hinder communications. Several r esearchers have investigated the impact of respirators on healthcare personnel.

Respirator Tolerance

Consistent use of PPE by healthcare personnel during exposure to

hazards is essential to achieve the be nefits afforded by the devices. One of the critical features in helping to achieve consistent compliance in the wearing of PPE may be the comfort and tolerability of the equipment

itself. Although most healthcare personnel a ppear to be assigned N95 respirators for use, elastomeric respirator s represent an alternative type of respiratory protection that could be used. Roberge and colleagues (2010c)reported the comfort responses of healthcare personnel wearing a halfface elastomeric respirator who completed exercise regimes for a 1-hour period. The healthcare personnel’s mean comfort scores were low, indicating that the elastomeric respirators were generally comfortable, andthe comfort scores were not significantly different from controls (no respirator). Complaints of subjective symptoms and design features of therespirator included facial heat, skin irritation, and weight of the respirator, among others. Little is known about the tolerabilityof healthcare personnel to wearing respirators, particularly during an influenza pandemic where they likely would be required to be worn fo r long periods of time within an 8- hour work shift over a duration involving a number of weeks or more. Radonovich and colleagues (2009) determined the mean tolerance time that healthcare personnel would be willi ng to wear a variety of respirator ensembles (including N95s, PAPRs, half-face elastomerics, and facemasks in various combinations) while performing their normal job duties. Healthcare personnel stopped wear ing their respirator ensemble before the end of an 8-hour shift in 59 percent of the total work shifts evaluated by the study. Reasons gi ven for discontinued wear included communication difficulties (visual, aud itory, or vocal), heat, pressure or pain, and dizziness or difficulty concentrating, among others. Median tolerance times varied by the respirator ensemble worn, ranging from 4.190 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

to 7.7 hours. Wearers of disposable models often complained of facial heat and pressure, while users of re usable models often reported communication problems. A cup-shaped N 95 with an exhalation valve had a greater median tolerance time (7.7 hours) compared to a similar model that was not equipped with a valve (5.8 hours). The ensemble combination of cup N95 plus a face mask had the shortest median tolerance time of 4.1 hours. The PAPR had a slightly lower median tolerance time (7.6 hours) than either the cup-shaped N95 with exhalation valve or face mask, which had the same median to lerance time (7.7 hours). Although the difference is not likely to be clinically significant, it is surprising that

the tolerance time for the PAPR was lower than that for the N95 with

exhalation valve. It is also interesti ng to note that the tolerance time for

the face mask was similar to both the PAPR and the N95 with exhalation valve. However, the N95 with exha lation valve had a higher number of complaints (24) than the PAPR (17) or face mask (17).Harber and colleagues (2009) evaluated a number of subjective tolerance measures to respirator use by subjects selected from the generalpopulation, including some with mild respiratory impairment, while engaging in exercise and work simulation. Respirators evaluated included half-face elastomerics and N95s. Under work simulation, the subjective tolerance measures (e.g., comfort, heat, speech) for all variables assessed, except heat, were more “adverse” for the elastomeric half-mask respirator than for the N95. The la rgest adverse subjective ratings were for comfort, face, breathing, heat, and heavy weight of the device. Thelargest differences between the two types of respirators were for subjective measures of nose impact and heavy weight, with the elastomeric model demonstrating the greater adve rse impact among subjects on these two measures. Overall, however, th e study concluded that while both respirator types were “relatively we ll tolerated,” N95 respirators may be preferable to elastomeric respirators. Although not much is known about what workers would like to see incorporated into future respiratordesigns to assist in increasing compliance, one recent study surveyed healthcare personnel to assess their perspectives on this issue (Baig et al., 2010). Of 149 survey respondents, only 24 percent reported that their N95 respirator was comfortable most of the time or always, and only 6 percent indicated that they would be able to tolerate wearing an N95 respirator continuously for an 8-hour shift. Overall, 56 percent of respondent s believe there is a need to develop a new N95 respirator for healthcare personnel, 44 percent preferred an N95 that does not require fit testing, and 60 percent preferred wearing aDESIGNING AND ENGINEERING EFFECTIVE PPE 91

disposable device. Problems identified by respondents that need to be addressed in future respirator design included discomfort, difficulty breathing, heat, and low tolerability for use over extended time periods.

Physiological Impact

The physiological impact of respirators on workers is an important factor in designing wearable PPE. Recent studies have investigated the physiological impact of respirators during physical tasks and while walking on a treadmill. Vojtko and collea gues (2008) found small but statistically significant increases in both inhalation and exhalation resistances of a face mask placed over an N95 filteri ng facepiece respirator for minute volumes of 25 and 40 L/min, but the total did not exceed NIOSH limits (although those are measured at 85 L/min). Although their study was performed with a simulator, the authors co ncluded that the slight increases in resistance should not impact the wearer’s respiratory effort.Bansal and colleagues (2009) assessed the impact of one dualcartridge elastomeric and one N95 half-face mask respirator on both normal and respiratory-impaired volunteers (respiratory impairmentswere listed as chronic rhinitis, mild chronic obstructive pulmonary disease, and mild asthma). No control condition was used. Sedentary (bolt sorting), low-intensity (walk across room and put papers in appropriate bins), and moderate-intensity (stock shelves with cereal boxes and juicejugs) tasks were included. The authors found small but statistically significant differences between the two respirators for inhalation time (longer for half-face models, 1.14 ve rsus 1.10), exhalation time (shorter for half-face models, 1.39 versus 1.44) , and increased duty cycle for halfface models (0.46 versus 0.45). Howeve r, the differences are not likely to be clinically significant. The authors stated that neither respirator should cause hypoventilation and that both types of respirators should be well tolerated for most individuals, includi ng those with mild respiratory impairments. Another study used thermal imaging to assess surface temperature of two N95 respirators and two N95 resp irators with exhalation valves from the same manufacturer (Monaghan et al., 2009). Respirators were placedon a headform with an Automated Breathing Metabolic Simulator supplying air at 100 percent relative humidity and 33°C at 10 L/min for an hour. The authors concluded that at the breathing rate used, exhalation valves provided no heat dissipation be nefits over a mask without one.92 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

However, they also noted that the exhalation valve was not activated at the low breathing rate. Roberge and colleagues (2010a,b,c) completed a number of studies that assessed the physiological impact of various respirators during a 1-hour treadmill walk at 1.7 and 2.5 mph. There were no significant differences between N95 filtering facepiece respirators with and without exhalation valves and the control in physio logical variables, exertion scores,or comfort scores. The comparison of the N95 with and without the exhalation valve found no differences in the partial pressure of carbon dioxide (CO 2 ). Similar results were reported for face masks worn over the

N95s either with or without the exhalation valve. The authors did note that face masks decreased oxygen leve ls in the filtering facepiece respirators at the low work rate and in the respirators with the exhalation valves at the higher work rate. An elastomeric air-purifying respirator resulted in decreased breathing rates and higher tidal volumes at both work rates, although the minute ventilation did not differ. While transcutaneous CO 2 values did not statistically differ (el astomeric air-purifying respirator versus control), some subjects had elevated levels that the authors suggested should be investigated further. The elastomeric air-purifying respirator imposed little additional physiological burden over an hour of wear at the work rates assessed. Exhalation valves in N95 respirators may decrease exhalation resistance and help dissipate heat and CO 2 build-up; however, at low flow rates, these benefits may not be realized. Monaghan and coworkers (2009)

noted that the exhalation valve was not activated at 10 L/min ventilation rate. This means wearers may not no tice any difference in thermal sensation of the face during sedentary or low-intensity activities. Roberge and colleagues (2010b) found that at low work rates, excess CO 2 was not a problem. Therefore, the benefit of the exhalation valve may be seen only at higher work rates. Healthy workers and those with m ild respiratory impairments should be able to physiologically tolerate re spirators. Little physiological burden should be imposed by filtering facepiece respirators (with or without a face mask) or by elastomeric respirators. However, the impact of filtering facepiece respirators on pregnant women is not well understood (Roberge, 2009). Respirators designed to accommodate the respiratory limitations of pregnant healthcare personnel may improve comfort and tolerability for other wearers (Roberge, 2009). Although loose-fitting PAPRs were not investigated, they should not impose a respiratory bur-DESIGNING AND ENGINEERING EFFECTIVE PPE 93

den due to their positive air flow. However, the weight of the blower may increase the physio logical workload.

Communications

Healthcare personnel must be able to communicate effectively andaccurately with each other and with patients while wearing PPE. Communications while wearing PPE typical of healthcare personnel has been investigated by Mendel and coll eagues (2008) and Radonovich and colleagues (2010). A third study involving air traffic controllers also provides useful information (Hah et al., 2009). Mendel and coworkers (2008) assessed the impact of face masks on speech intelligibility using the Connected Speech Test with normal and hearing-impaired listeners in either a quiet room or with prerecorded noise from a dental drill played at 45 dBA. No impact was reported on speech intelligibility for either the nor mal or hearing-impaired listeners. A small but significant difference in scores for both mask and no-mask scores was noted due to background noise. Radonovich and coauthors (2010) used a Modified Rhyme Test with modified scoring to investigatethe impact of face masks and respirators on speech communications. Reported scores were not corrected for guessing. The first set of trials was performed in an intensive care unit (ICU) room with simulated noise,with only the speaker wearing the device. The scores of the N95 cupshaped respirator, duck bill N95, face mask, and control were statistically

the same at both 3 and 7 feet in an ICU room with simulated noise. Theelastomeric half-mask respirator with exhalation valve was the worst performer at 72 percent, scoring even lower than the loose-fitting PAPR (84 percent). However, the cup-shaped N95 with a face mask, cup-shaped N95 with an exhalation valve, PAPR , and cup-shaped N95 with exhalation valve and overlying face mask all had scores significantly lower

than the control. The second set of trials was performed with elastomeric respirators

with and without exhalation valves in an audiometric test room with background noise. All six respirators had scores significantly differentfrom the control, and the three respirators with speech augmentation performed better than those without augmen tation. The final set of trials was performed in an audiometric test room with background noise with only the listener wearing a PAPR. The PAPR significantly impacted scores (79 percent) compared to the control (90 percent). Intelligibility was94 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

higher at 3 feet than at 7 feet, but was not significantly different. Control scores were higher in the audiometric room than in the ICU, possibly due to reverberation and distractions in the ICU area. The authors suggested that respirators should be devel oped that improve communication among coworkers in noisy medical settings. Hah and colleagues (2009) investigated loose-fitting PAPRs and

N95s for air traffic controllers who would have to work during an influenza pandemic. Although they focused on communications using headsets, some of their observations are applicable to the healthcare environment. The blowers for the three loose-fitting PAPRs that they investigated created noise between 52 dBA and 81 dBA. As expected, the respirator with the highest blower noise had the lowest speech intelligibility scores. Although the authors used a modified rhyme test that was different than the test employed by Radonovich and colleagues (2010), these authors found error rates of 3 to 18 percent with the PAPRs for

electronic communications and error rat es of 32 to 55 percent with 3 subjects performing face-to-face communications. The quietest PAPR hadthe lowest error rates. Their N95 tests with two filtering facepiece respirators and one elastomeric respirator had error rates of 0 to 16 percent, though only 2 volunteers were used. The highest errors were with theelastomeric respirator, similar to the Radonovich findings. The elastomeric respirator was rated as obstructing maintenance tasks more than the filtering facepiece respirator. These three studies showed that background noise, whether it is from a dental drill, ICU room, or PAPR, has a detrimental effect on speechcommunications. Efforts should be made to decrease ambient noise, select PAPRs with low-noise blowers, or develop and certify PAPRs with lower flow rates that could be used by healthcare personnel. Speechaugmentation devices or voice projection units may also improve communications. The Department of Home land Security has a current Small Business Innovation Research project (Topic Number H-SB09.2-006) (Department of Homeland Security, 2009) that is investigating improved speech intelligibility in noise for first responders. Some of the techniquesbeing developed may be applicable to PAPRs and elastomerics, the respirators that the studies by Radonovich and Hah and colleagues identified as having the greatest decrement on speech recognition. Additionally, theimpact of decreased communications on patient care and procedural outcome is unknown.DESIGNING AND ENGINEERING EFFECTIVE PPE 95

Current Research Directions

NIOSH recently supported a research effort (Brosseau, 2009) that examined ways to improve fit for ha lf-mask respirators. The effort culminated in a workshop that included presentations on recent research efforts, innovation, design, and impediments to bring new products to

market as well as breakout sessions dur ing which participants discussed characteristics of good design, areas where research is needed, wearer characteristics that impact fit, and necessary design changes. Characteristics of good design identified during the breakout session included “low weight, able to fit many facial profiles, does not impair field of vision, uniform pressure on the face, good strap design, can be easily donned multiple times, has a limited number of parts, does not interfere with communication and is portable and easy to store” (Brosseau, 2009, p. 33). Participants identified the following as important research areas:decontaminating respirators, cross-contamination occurrence during repeat donning, efficacy of biocidal co atings, and whether respirator use reduces infection rates in emergency departments. Wearer characteristics that the group identified as contributin g to fit were symmetry, chin characteristics, sweat, nose dimension, and head dimension. Participants also

identified the need for a user seal check that works and said they would like continuous fit checking rather than a no-fit test. Overarching recommendations for future research were to further investigate the relationship between respirator design and fit; to clarify the impact of facepiece design, facepiece sizes, and aging on the relationship between facial measurements and respirator f it; to determine how user seal check impacts respirator fit; to explore new methods for checking facepiece seals; and to determine the impact of environmental conditions and other protective equipment on respirator fit. The Department of Veterans Affairs is leading a collaborative effort

with the National Personal Protec tive Technology Laboratory (NPPTL) to develop a respirator specifically designed for healthcare personnel entitled Project Better Respiratory Equipment Using Advanced Technologies for Healthcare Employees (B.R.E.A.T.H.E.) (Department of Veterans Affairs, 2010). The project has been divided into four stages: interagency working group informat ion exchange, prototype development, prototype lab and human subject testing, and commercialization. Nine federal departments and agencies are participating in the workinggroup. The group met in 2008 to discuss issues of safety and effectiveness, impact on occupational activiti es, comfort and tolerability, and96 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

healthcare policies and practices. On December 14, 2009, a notice was placed in the Federal Register describing the project and seeking letters of interest from commercial organizat ions with the ability to design and manufacture a respirator that meets th e needs of Project B.R.E.A.T.H.E. (Federal Register, 2009). It is anticipat ed that the report will be published

in 2011.

Summary

Efforts are under way to develop more comfortable and easier to fit respirators that will be more conducive to interactions with patients, colleagues, and family members. Research to date has shown that the lowinhalation and exhalation resistance rates of filtering facepiece respirators do not significantly impact respiration. Although hypoventilation occurs with full-facepiece air-purifyi ng respirators, neither the Bansal and colleagues (2009) nor the Robe rge and colleagues (2010a,b,c) studies showed any evidence of such a burden with N95 filtering facepiecerespirators or elastomeric respirators. Respirators do impact communications. However, the impact of decreased speech intelligibility on task performance is unknown. Loose-fitti ng PAPRs may make many healthcare tasks more difficult because of their bulkiness, added weight of the blower, flexible visor, and blower noise.

Protective Clothing

Gowns and other forms of protective clothing are designed forhealthcare personnel primarily to act as a barrier to prevent the penetration of liquids or solids from coming into contact with the wearer’s skin and clothing. As the barrier properties of the protective clothing increase, the breathability of the material gene rally decreases, which then has the potential to impact comfort and tolera bility (i.e., cause an increase in heat levels experienced by the wearer). A recent study has demonstrated thatmedical personnel who wear chemical protective clothing while performing basic life-saving tasks (e.g., connecting an intravenous [IV] line) experience discomfort and heat stress along with needing more time to perform the task (Rissanen et al., 2008). Using phase-change materials for the construction of protective clothi ng offers the potential to help reduce heat stress and improve thermal comfort for healthcare personnel.DESIGNING AND ENGINEERING EFFECTIVE PPE 97

Phase-change materials provide coolin g by absorbing heat when they change from a solid to a liquid state. A surgeon wearing a vest containing phase-change materials reported subjective improvements in thermal comfort over that compared to regular clothing (Reinertsen et al., 2008).A 2008 review of protective clothing for healthcare personnel highlighted additional issues that are considered in designing protective clothing, including antibacterial finish ing treatments, the impact of temperature and relative humidity in the work environment, the use of multiple layers, and changes that can r esult from laundering or cleaning that might impact the protective effects of the clothing (Laing, 2008). The issue of laundering was further re viewed by Wilson and colleagues(2007), who assessed the limited available literature and found that industrial laundering and home launderi ng both were effective in decontamination of healthcare clothing, including lab coats.A large-scale study (Manian and Ponzillo, 2007) examined compliance of gown wear for hospital pers onnel (n = 1,150) and visitors (n =392) to general wards and an ICU. Overall compliance by hospital personnel was 76 percent, while visitors complied 65 percent of the time.However, there were differences among healthcare personnel by occupation, with respiratory therapists ha ving the highest compliance rate (96 percent) and physicians having the lo west (67 percent). Female healthcare personnel (79 percent) were more likely than males (66 percent) to wear gowns. Overall compliance was higher in the ICU (83 percent) than in the general wards (71 percent). Th e study authors did not note whetheran individual healthcare professional was included in multiple observations. Additionally, knowing they were being watched may have influenced the decision to wear a gown. The reasons for non-compliance are unknown. However, the study showed that improvement is needed in gown compliance and that educational efforts should focus on male healthcare personnel as well as both hea lthcare personnel and visitors to general wards.

Gloves

Gloves also serve as barrier protection, although the role of gloves in preventing the transmission of influenza or other respiratory viruses is unknown. For bloodborne pathogens, gloves can prevent transmission through direct contact with non-intact skin. Gloves can provide a barrier

between contaminated surfaces and the skin and can serve as a reminder98 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

to avoid self-inoculation. However, gloved hands can be a means of selfinoculation if healthcare personnel inadvertently touch their mouth, nose, or eyes with contaminated hands (IOM, 2008). Changing gloves between patients and paying rigorous attention to hand hygiene protocols can reduce contamination between patients or self-inoculation. Glove donning and doffing procedures have been ex amined to reduce contamination (Jones et al., 2010; Newman et al., 2007). As with gowns and protective clothi ng, one active area of research is the use of antiviral coatings or ot her virus-inhibiting mechanisms. Caillot and Voiglio (2008) examined the tolerance and ease of use of gloves that had a disinfecting agent between the two layers of the glove. They found that tactile feeling, grip quality, a nd other measures were comparable to double latex gloving. Other areas of study are indicators of perforation in gloves, double gloving, and tolerance of powder or other irritant reducers (e.g., aloe vera) (Fry et al., 2010; Hubner et al., 2010; Korniewicz and El Masri, 2007; Partecke et al., 2009).

Eye Protection and Face Shields

Transmission of influenza through the mucosa of the eyes, nose, and mouth is plausible, but not confirme d (Chan et al., 2010). Case reports of conjunctivitis have been noted with the H7N7 avian influenza virus (Fouchier et al., 2004). Protective ey ewear and face shields can reduce self-inoculation and may provide protection against droplet spray. Little

is known about how well these device s protect the wearer from directcontact, when this protection is needed regarding transmission from patients to healthcare personnel, and the extent to which extra precautions are needed during aerosol-generating procedures. Face shields may be a useful form of protection in lieu of face masks for workers exposed to droplet spray, particularly regarding comfort and tolerability issues, reduced breathing resistance, and improved speech communication. Decontamination and reuse may be possible for faceshields, but much remains to be learned. It is unknown whether healthcare personnel would find face shields to be an acceptable alternative to

masks and whether face shields would provide similar or superior (by protecting the eyes) protection to masks. The recent literature on eye protection and face shields appears to be limited and focused on blood-splash concerns. A study by Mansour and colleagues (2009) examined eye protection during orthopedic surgeryDESIGNING AND ENGINEERING EFFECTIVE PPE 99

and made comparisons of several types of glasses, loupes, or face shields. Modern prescription glasses offered no benefit over the control condition, with both resulting in contamination rates of 83 percent. These rates were significantly lower for a ll other eye-protective devices (50 percent for standard surgical telesc opic loupes, 30 percent for face-mask and eye-shield combinations, and 3 pe rcent for disposable glasses). Studies have also examined eye protecti on for blood-splash concerns (Davies et al., 2007; Wines et al., 2008) and found that face masks, eye shields, and glasses worn by surgeons and scrub nurses had high incidence ofblood and body-fluid splashes. Similar studies would be useful to evaluate the exposure of healthcare pers onnel to droplet spray during patient care and to assess which types and combinations of eye protection and face shields provide the greatest protection.

Cross-Cutting Issues: Task Perf ormance and New Materials

Task Performance

The ability of medical staff to perform tasks and medical procedures while wearing PPE is a concern. Se veral recent studies assessed the impact of various levels of PPE on th e ability of healthcare personnel to perform medical tasks. The ability to complete a simulated resuscitation was investigated for paramedics wearing an air-purifying respirator and PAPR (Schumacher et al., 2009) and for paramedics and anesthesia trainees wearing an air-purifying respirator with a binocular or panoramic lens (Brinker et al., 2007; Schumacher et al., 2008). No differences in task completion times were found in any of these three studies. Delays resulting from donning a protective gown were seen in the initiation ofchest compressions and cardiopulmonary resuscitation in a study of firefighter defibrillator instructors who were videotaped performing cardiac arrest scenarios (Watson et al., 2008). Rissanen and colleagues (2008)found that completing two medical tasks while wearing chemical, biological, radiological, and nuclear (CBRN) PPE, including an impregnated charcoal suit, overalls, an air-purifying respirator, and cotton and rubber gloves, took longer—19 percent for ventilation and 18 percent for connecting an IV line. Udayasiri a nd colleagues (2007) assessed the abilityof emergency department doctors and nurses to perform trauma resuscitation in level C PPE (air-purifying respirator, hooded suit, and inner and100 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

outer gloves) versus gowns and glov es. Although volunteers believed the PPE impaired pulse assessment, IV cannulation, IV-line attachment, mini-jet use, bag and mask ventilation, and communication, only thetime to control hemorrhage (38 to 47 sec, p = 0.02) was significantly impacted. Castle and colleagues (2009) assessed the ability of 64 clinicians to perform intubation, laryngeal mask airway placement, and insertion of

an IV cannula and intraosseous needle twice while in CBRN PPE andonce unsuited. Eight percent of intubation and 12 percent of IV cannulation attempts were unsuccessful in CBRN PPE. Donning of PPE has also been noted to delay the onset of patient care. Watson and colleagues (2009) conducted a simulation of a patient on a pediatric ward who developed respiratory failure. Donning of full PPE delayed the first response to th e simulated “code” situation by 2 minutes, and other care measures were also delayed.These results show that many medical tasks can be performed in various levels of PPE, but that the tasks may take longer. No studies wereperformed that assessed the impact of filtering facepiece respirators, elastomeric respirators, or loose-fitting PAPRs on task performance. However, a filtering facepiece respirator or elastomeric respirator is unlikely to have a greater impact on task performance than a full-facepiece airpurifying respirator. The bulkiness and visor of a loose-fitting PAPR may have a different impact on perfo rmance than the more close-fittingair-purifying respirator and PAPR used in these studies. Castle and colleagues (2009) report that the reason some tasks could not be completed may be because clinicians were wearing full chemical, biological suits. The individual impact of respirators, suits, and rubber gloves cannot be separated. Additional studies that asse ss the impact on task performance of PPE likely to be worn during an influenza pandemic or outbreak of other viral respiratory diseases are warranted.

Using Multiple Types of PPE: Integration and Use Issues

Because healthcare personnel frequently need to use several PPEitems for protection against bloodborne or other infectious agents, including a respirator, gloves, a gown, eye or face protection, and in somecases head and shoe coverings, issues arise about the integration and interface of these items and how best to don and doff the PPE to ensure that maximum protection is provide d and contaminati on is avoided.

Workers in fields such as law enforc ement, firefighting, and health careDESIGNING AND ENGINEERING EFFECTIVE PPE 101

have critical needs to be able to perform specific tasks while wearingmultiple types and models of PPE. The impact of PPE on occupationspecific tasks and the equipment used to perform those tasks should be considered in designing and selecting PPE. Studies on the impact of PPE on medical tasks have focused on chemical and biological protective equipment (Brinker et al., 2007; Castle et al., 2009; Rissanen et al., 2008; Schumacher et al., 2008, 2009; Udayasiri et al., 2007). These studies did not address healthcare-specificPPE used to protect against influenza transmission. The impact of individual PPE items was not assessed, so it is not known whether the respirator, gloves, or suits or a combination of equipment caused the interference. Additionally, face shie lds were not used in these studies. Integration of common healthcare PPE with medical equipment should be assessed and their impact on task performance determined.

SUMMARY OF PROGRESS

Personal protective equipment is a critical component in the hierarchy of controls used to protect healthcare personnel from influenza andother viral respiratory diseases. Understanding the functional issues related to the design of PPE as well as the factors that impact use are critical to ensuring that healthcare personnel are adequately protected, comfortable, and able to perform th eir jobs. Important advances havebeen made in some areas since the 2008 IOM report, but other areas, particularly regarding improvements in gowns, gloves, face masks, and face shields, need to be more fully a ddressed. Much research has been doneregarding filtration of respirator media, but ways to improve fit, including new technologies specifically for filtering facepiece respirators, need

more research because face seal l eakage greatly exceeds filter penetration in the overall TIL of respirators. The physiological impact of respirators has been studied in-depth, but research in this area is lacking for other types of PPE. Integration issues concerning PPE and medical equipment and the impact on operationa l performance have not been adequately studied. Effective decontamination methods that do not impact the physical characteristics of respirators have been studied for some types of respirators, but with inconclusive results. Finally, the characteristics of a respirator that would specifically a ddress the needs of healthcare personnel (e.g., patient–provider interaction, co mfort, reduced physiological burden)102 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

have been identified. Addressing thes e issues is important for developing PPE for healthcare personnel that is safe, effective, and comfortable.

FINDINGS AND RESEARCH NEEDS

This chapter provides an overview of the range of ongoing work ondesigning and engineering effective PPE to prevent transmission of influenza and other viral respiratory diseases. At its June 2010 workshop and through its literature review, th e committee realized that many research efforts have been completed recently and that ongoing research

efforts in this area continue. The cha llenge will be to sustain these efforts

and to broaden them into areas that will result in wearable and effectivePPE for healthcare personnel. Box 3-1 highlights the committee’s findings in this area.

• Wearability:

o Respirators: Continue examining the features of N95s, PAPRs, and elastomeric respirators that impact comfort and tolerability among healthcare personnel. Identify alterations in respirator design and construction that show promise in improving problem features that adversely impact comfort and tolerability.

o Other PPE: Initiate research to identify factors affecting the comfort and tolerability of protective eyewear and clothing,and identify changes having the potential to positively influence comfort and tolerability. Evaluate differences between short- and long-term use of PPE as it affects comfort and tolerability. Develop and field test new designs and features forPPE for healthcare personnel that offer potential for improving comfort and tolerability.

• Decontamination and Feasibility of Reuse:

o Decontamination methods: Continue to assess promising decontamination methods for all types of PPE, including research on the impact of decontamination methods on respirator protection and on the physical characteristics ofDESIGNING AND ENGINEERING EFFECTIVE PPE 103

BOX 3-1 Findings

• Respirators are designed to provide respiratory protection, and respirators certified by the National Institute for Occupational Safety and Health are tested to provide effective filtra tion. Issues remain regarding respirator fit, which currently depends on fit testing and user seal checks. Efforts focused on addressing total inward leakage may resolve some of these issues, and research on respirat ors that do not require fit testing is

needed.

• Face masks and face shields do not provide a tight seal to the wearer’s face. Laboratory research to date on the performance of face masks hasfocused on inhalable particulates, and there has been little or no research as to the performance of these devices on droplet spray.

• There is a lack of knowledge as to the performance of eye protection, face shields, gloves and gowns, and other PPE in protecting the wearer from influenza and other respiratory viruses.

the respirator (inner, middle, and outer layers). Assess decontamination effectiveness using either influenza virus or a suitable surrogate.

o Feasibility of reuse: Develop a protocol for donning and doffing PPE to minimize self-inoculation.

• TIL and Protection:

o TIL: Finish development of the TIL certification requirements for half-mask air-purifying respirators. Assess TIL of very small particles (< 100 nm) with respirators.

o Face masks and face shields: Assess the TIL of face masks against droplet spray. Conduct research using manned and

unmanned tests to determine if face shields can offer suitable alternative protection to goggles and/or face masks to protect healthcare personnel against droplet spray.

o Fit: Evaluate the impact of facepiece materials and design on improving the fit of filtering facepiece respirators. Developimproved and simpler fit testing methods. Examine the effectiveness of performing a userseal check for an N95 respirator each time it is donned.

o Workplace protection studies: Conduct workplace protection studies to assess protection during typical tasks and time104 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

changes in protection. Determine how using typical instruments impacts protection, and identify integration issues.

• Equipment and Technologies:

o Integration: Conduct human factors (field of view, visual acuity, communication) and operational performance studiesto assess the ability of healthcare personnel to perform medical procedures in typical healthcare-specific PPE ensembles.

o New technologies: Continue development of an air-purifying respirator that specifically addresses the needs of healthcare personnel. New materials and technologies should be developed specifically for filtering facepiece respirators to improve fit, comfort, and tolerability. A new low-noise, lightweight, PAPR and a face shield that is reusable and easy to clean should be designed and developed. The efficacy andeffectiveness of antiviral-coated PPE and impacts on maintenance and reuse of PPE should be assessed.

RECOMMENDATIONS

Recommendation: Continue and Expand Research on PPE

for Healthcare Personnel NPPTL and other agencies, private-sector companies, and other organizations should continue to advance research indesigning and evaluating the effectiveness of respirator protection for healthcare personnel and expand its research efforts to improve and evaluate the effectiveness of gloves, gowns, eye protection, face shie lds, and face masks in preventing the transmission of influenza or other viral respiratory diseases. Areas of focu sed research needs include

• effectiveness in preventing fomite, droplet spray, or aerosol transmission;

• decontamination and feasibility of reuse;

• comfort, fit, and usability;

• impact on task performance; and

• development of technologies specifically for healthcare personnel.DESIGNING AND ENGINEERING EFFECTIVE PPE 105

Recommendation: Improve Fit Test Methods and Evaluate

User Seal Checks NPPTL should develop novel, simpler fit test methods and evaluate the effectiveness of performing user seal checks on N95 respirators.

Recommendation: Develop and Certify PAPRs for Healthcare PersonnelNPPTL should develop certification requirements for a lownoise, loose-fitting PAPR for healthcare personnel.

Recommendation: Examine the Effectiveness of Face Masks

and Face Shields as PPE NPPTL should investigate the effectiveness of face masks and face shields in preventing transmission of viral respiratory

diseases.

REFERENCES

Au, S. S., C. D. Gomersall, P. Leung, and P. T. Li. 2010. A randomised controlled pilot study to compare filtra tion factor of a novel non-fit-tested high-efficiency particulate air (HEPA) filtering facemask with a fit-tested

N95 mask. Journal of Hospital Infection 76(1):23-25. Baig, A. S., C. Knapp, A. E. Eagan, and L. J. Radonovich, Jr. 2010. Health care workers’ views about respirator use and features that should be included in the next generation of respirators. American Journal of Infection Control 38(1):18-25. Bansal, S., P. Harber, D. Yun, D. Liu, Y. Liu, S. Wu, D. Ng, and S. Santiago. 2009. Respirator physiological effects under simulated work conditions. Journal of Occupational and Environmental Hygiene 6(4):221-227. Borkow, G., S. S. Zhou, T. Page, and J. Gabbay. 2010. A novel anti-influenza copper oxide containing respiratory face mask. PLoS ONE 5(6):e11295. Brinker, A., S. A. Gray, and J. Schumacher. 2007. Influence of air-purifying respirators on the simulated first response emergency treatment of CBRN

victims. Resuscitation 74(2):310-316. Brosseau, L. M. 2009. Toward better fitting respirators: No fit test respirator workshop and research roadmap, RFQ 2008-Q-10205 . http://www.sph. umn.edu/ce/presentations/docs/Final_NoFitRespiratorReport_July28_2009. pdf (accessed November 30, 2010).106 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Brosseau, L. M., and K. Harriman. 2007. Commentary on “in vivo protective performance of N95 respirator and surgical facemask.” American Journal of

Industrial Medicine 50(12):1025-1026; author reply 1027-1029. Caillot, J. L., and E. J. Voiglio. 2008. First clinical study of a new virusinhibiting surgical glove. Swiss Medical Weekly 138(1-2):18-22. Casanova, L., W. A. Rutala, D. J. Weber, and M. D. Sobsey. 2009. Methods for the recovery of a model virus fr om healthcare personal protective equipment. Journal of Applied Microbiology 106(4):1244-1251. Castle, N., R. Owen, M. Hann, S. Clark, D. Reeves, and I. Gurney. 2009. Impact of chemical, biological, radiation, and nuclear personal protective equipment on the performance of lo w- and high-dexterity airway and

vascular access skills. Resuscitation 80(11):1290-1295. Chan, M. C., R. W. Chan, W. C. Yu, C. C. Ho, K. M. Yuen, J. H. Fong, L. L. Tang, W. W. Lai, A. C. Lo, W. H. Chui, A. D. Sihoe, D. L. Kwong, D. S. Wong, G. S. Tsao, L. L. Poon, Y. Guan , J. M. Nicholls, and J. S. Peiris. 2010. Tropism and innate host responses of the 2009 pandemic H1N1 influenza virus in ex vivo and in vitro cultures of human conjunctiva and respiratory tract. American Journal of Pathology 176(4):1828-1840. Cho, K. J., T. Reponen, R. McKay, R. Shukla, H. Haruta, P. Sekar, and S. A. Grinshpun. 2010. Large particle penetr ation through N95 respirator filters and facepiece leaks with cyclic flow. Annals of Occupational Hygiene 54(1):68-77. Coffey, C. C., R. B. Lawrence, D. L. Campbell, Z. Zhuang, C. A. Calvert, and P. A. Jensen. 2004. Fitting characteristic s of eighteen N95 filtering-facepiece respirators. Journal of Occupational and Environmental Hygiene 1(4):262-

271. Davies, C. G., M. N. Khan, A. S. Ghauri, and C. J. Ranaboldo. 2007. Blood and body fluid splashes during surgery—the need for eye protection and masks. Annals of the Royal College of Surgeons of England 89(8):770-772. Department of Homeland Security. 2009. Noise cancellation for voice operated switch (VOX) communications: Small Business Innovation Research project topic number H-SB09.2-006 . https://www.sbir.dhs .gov/refer ence/DHS_ SBIR-2009.2_Full_ Solicitation.doc (accesse d November 4, 2010). Department of Veterans Affairs. 2010. National Center for Occupational Health and Infection Control: Key projects . http://www.publichealth.va.gov/ employeehealth/epidemiccontrol/project s.asp#breathe (accessed November 4, 2010). Diaz, K. T., and G. C. Smaldone. 2010. Quantifying exposure risk: Surgical masks and respirators. American Journal of Infection Control 38(7):501-

508. Duling, M. G., R. B. Lawrence, J. E. Sl aven, and C. C. Coffey. 2007. Simulated workplace protection fact ors for half-facepiece respiratory protective

devices. Journal of Occupational and Environmental Hygiene 4(6):420-

431.DESIGNING AND ENGINEERING EFFECTIVE PPE 107

Eninger, R. M., T. Honda, A. Adhikari , H. Heinonen-Tanski, T. Reponen, and S. A. Grinshpun. 2008a. Filter performance of N99 and N95 facepiece respirators against viruses and ultrafine particles. Annals of Occupational Hygiene 52(5):385-396. Eninger, R. M., T. Honda, T. Reponen, R. McKay, and S. A. Grinshpun. 2008b. What does respirator certification te ll us about filtration of ultrafine particles? Journal of Occupational and Environmental Hygiene 5(5):286-

295. Eshbaugh, J. P., P. D. Gardner, A. W. Richardson, and K. C. Hofacre. 2009. N95 and P100 respirator filter efficien cy under high constant and cyclic

flow. Journal of Occupational and Environmental Hygiene 6(1):52-61. Federal Register. 2009. Notice: Department of Vetera ns Affairs: Project Better Respiratory Equipment Using Advanced Technologies for Healthcare Employees (B.R.E.A.T.H.E.) . http://frwebgate3.access. gpo.gov/cgi-bin/PDFgate.cgi?WAISdocID=ceFTAw/1/2/0&WAISaction=retrieve (accessed November 4, 2010). Fisher, E., and R. Shaffer. 2010. Survival of bacteriophage MS2 on filtering facepiece respirator coupons. Applied Biosafety 15(2):71-76. Fisher, E., S. Rengasamy, D. Viscusi, E. Vo, and R. Shaffer. 2009. Development of a test system to apply virus-containing particles to filtering facepiece respirators for the evaluation of decontamination procedures. Applied and Environmental Microbiology 75(6):1500-1507. Fouchier, R. A. M., P. M. Schneeberger, F. W. Rozendaal, J. M. Broekman, S. A. G. Kemink, V. Munster, T. Ku iken, G. F. Rimmelzwaan, M. Schutten, G. J. J. van Doornum, G. Koch, A. Bosman, M. Koopmans, and A. D. M. E. Osterhaus. 2004. Avian influenza A virus (H7N7) associated with human conjunctivitis and a fatal case of acute respiratory distress syndrome. Proceedings of the National Ac ademy of Sciences (U.S.A.) 101(5):1356-

1361. Fry, D. E., W. E. Harris, E. N. Kohnke, and C. L. Twomey. 2010. Influence of double-gloving on manual dexterity and tactile sensation of surgeons. Journal of the American College of Surgeons 210(3):325-330. Grinshpun, S. A., H. Haruta, R. M. Enin ger, T. Reponen, R. T. McKay, and

S. A. Lee. 2009. Performance of an N95 filtering facepiece particulate respirator and a surgical mask during human breathing: Two pathways for particle penetration. Journal of Occupational and Environmental Hygiene 6(10):593-603. Hah, S., T. Yuditsky, K. A. Schulz, H. Dorsey, A. R. Deshmukh, and J. Sharra.

2009. Evaluation of human performance while wearing respirators. http://hf.tc.faa.gov/technotes/dot-faa-tc -09-10.pdf (accessed November 3, 2010). Harber, P., S. Bansal, S. Santiago, D. Liu, D. Yun, D. Ng, Y. Liu, and S. Wu. 2009. Multidomain subjective response to respirator use during simulated

work. Journal of Occupational and Environmental Medicine 51(1):38-45.108 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Heimbuch, B. K., K. Kinney, B. Nichols, and J. D. Wander. 2009. The dry aerosol deposition device (DADD): An instrument for depositing microbial

aerosols onto surfaces. Journal of Microbiological Methods 78(3):255-259. Huang, J. T., and V. I. Huang. 2007. Evaluation of the efficiency of medical

masks and the creation of new medical masks. Journal of International

Medical Research 35(2):213-223. Hubner, N. O., A. M. Goerdt, N. Stanislawski, O. Assadian, C. D. Heidecke, A. Kramer, and L. I. Partecke. 2010. Bacterial migration through punctured surgical gloves under r eal surgical conditions. BMC Infectious Diseases

10:192. IOM (Institute of Medicine). 2008. Preparing for an influenza pandemic: Personal protective equipmen t for healthcare workers . Washington, DC:

The National Academies Press. Janssen, L. L., T. J. Nelson, and K. T. Cuta. 2007. Workplace protection factors for an N95 filtering facepiece respirator. Journal of Occupational and Environmental Hygiene 4(9):698-707. Johnson, A. T., F. C. Koh, S. Jamshidi, and T. E. Rehak. 2008. Human subject testing of leakage in a loose-fitting papr. Journal of Occupational and Environmental Hygiene 5(5):325-329. Johnson, D. F., J. D. Druce, C. Birch, and M. L. Grayson. 2009. A quantitative assessment of the efficacy of surgical and N95 masks to filter influenza virus in patients with acute influenza infection. Clinical Infectious Diseases 49(2):275-277. Jones, C., B. Brooker, and M. Genon. 2010. Comparison of open and closed staff-assisted glove donning on the nature of surgical glove cuff

contamination. Australian and New Zealand Journal of Surgery 80(3):174-

177. Korniewicz, D. M., and M. El Masri. 2007. Effect of aloe-vera impregnated gloves on hand hygiene attitudes of health care workers. MEDSURG Nursing 16(4):247-252. Laing, R. M. 2008. Protection provided by clothing and textiles against potential hazards in the operating theatre. International Journal of Occupational and Safety Ergonomics 14(1):107-115. Lee, J. H., C. Y. Wu, K. M. Wysocki, S. Farrah, and J. Wander. 2008a. Efficacy

of iodine-treated biocidal filter me dia against bacterial spore aerosols. Journal of Applied Microbiology 105(5):1318-1326. Lee, J. H., C. Y. Wu, C. N. Lee, D. Anwar, K. M. Wysocki, D. A. Lundgren, S. Farrah, J. Wander, and B. K. Heimbuch. 2009. Assessment of iodine-treated filter media for removal and inactivation of MS2 bacteriophage aerosols. Journal of Applied Microbiology 107(6):1912-1923. Lee, M. C., S. Takaya, R. Long, and A. M. Joffe. 2008b. Respirator-fit testing: Does it ensure the protection of healthcare workers against respirable particles carrying pathogens? Infection Control and Hospital Epidemiology 29(12):1149-1156.DESIGNING AND ENGINEERING EFFECTIVE PPE 109

Lee, S. A., S. A. Grinshpun, and T. Reponen. 2008c. Respiratory performance offered by N95 respirators and surgical masks: Human subject evaluation with NaCl aerosol representing bacterial and viral particle size range. Annals of Occupational Hygiene 52(3):177-185. Li, Y., T. Wong, J. Chung, Y. P. Guo, J. Y. Hu, Y. T. Guan, L. Yao, Q. W. Song, and E. Newton. 2006. In vivo protective performance of N95 respirator and surgical facemask. American Journal of Industrial Medicine 49(12):1056-1065. Manian, F. A., and J. J. Ponzillo. 2007. Compliance with routine use of gowns by healthcare workers (HCWs) and non-HCW visitors on entry into the rooms of patients under contact precautions. Infection Control and Hospital Epidemiology 28(3):337-340. Mansour, A. A., 3rd, J. L. Even, S. Phillips, and J. L. Halpern. 2009. Eye protection in orthopaedic surgery. An in vitro study of various forms of eye protection and their effectiveness. Journal of Bone and Joint Surgery 91(5):1050-1054. McMahon, E., K. Wada, and A. Dufresne. 2008. Implementing fit testing for N95 filtering facepiece respirators: Practical information from a large cohort of hospital workers. American Journal of Infection Control 36(4):298-300. Mendel, L. L., J. A. Gardino, and S. R. Atcherson. 2008. Speech understanding using surgical masks: A problem in health care? Journal of the American Academy of Audiology 19(9):686-695. Monaghan, W. D., M. R. Roberge, M. Rengasamy, and R. J. Roberge. 2009. Thermal imaging comparison of maxi mum surface temperatures achieved on N95 filtering facepiece respirators with and without exhalation valves at sedentary breathing volumes. Journal of the Intern ational Society for Respiratory Protection 26:12-19. Newman, J. B., M. Bullock, and R. Goyal. 2007. Comparison of glove donning techniques for the likelihood of gown contamination. An infection control study. Acta Orthopaedica Belgica 73(6):765-771. Oberg, T., and L. M. Brosseau. 2008. Su rgical mask filter and fit performance. American Journal of Infection Control 36(4):276-282. Oestenstad, R. K., and A. A. Bartolucci . 2010. Factors affec ting the location and shape of face seal leak sites on half-mask respirators. Journal of Occupational and Environmental Hygiene 7(6):332-341. Oestenstad, R. K., L. J. Elliott, and T. M. Beasley. 2007. The effect of gender and respirator brand on the associa tion of respirator fit with facial

dimensions. Journal of Occupational and Environmental Hygiene 4(12):923-930. Oxford, J. S., R. Lambkin, M. Guralnik, R. A. Rosenbloom, M. P. Petteruti, K. Digian, and C. Lefante. 2007. Preclinical in vitro activity of QR-435 against influenza A virus as a virucide and in paper masks for prevention of viral

transmission. American Journal of Therapeutics 14(5):455-461.110 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Partecke, L. I., A. M. Goerdt, I. Langner, B. Jaeger, O. Assadian, C. D. Heidecke, A. Kramer, and N. O. Huebner. 2009. Incidence of microperforation for surgical gloves depends on duration of wear. Infection Control and Hospital Epidemiology 30(5):409-414. Radonovich, L. J., Jr., J. Cheng, B. V. Shenal, M. Hodgson, and B. S. Bender. 2009. Respirator tolerance in health care workers. Journal of the American

Medical Association 301(1):36-38. Radonovich, L. J., Jr., R. Yanke, J. Cheng, and B. Bender. 2010. Diminished speech intelligibility associated with certain types of respirators worn by

healthcare workers. Journal of Occupational and Environmental Hygiene 7(1):63-70. Reinertsen, R. E., H. Faerevik, K. Holbo, R. Nesbakken, J. Reitan, A. Royset, and M. Suong Le Thi. 2008. Optimizing the performance of phase-change materials in personal prot ective clothing systems. International Journal of Occupational Safety and Ergonomics 14(1):43-53. Rengasamy, S., W. P. King, B. C. Eimer, and R. E. Shaffer. 2008. Filtration performance of NIOSH-approved N95 and P100 filtering facepiece respirators against 4 to 30 nanometer-size nanoparticles. Journal of Occupational and Environmental Hygiene 5(9):556-564. Rengasamy, S., B. C. Eimer, and R. E. Shaffer. 2009. Comparison of nanoparticle filtration performance of NIOSH-approved and CE-marked particulate filtering f acepiece respirators. Annals of Occupational Hygiene 53(2):117-128. Rengasamy, S., B. Eimer, and R. E. Shaffer. 2010a. Simple respiratory protection—evaluation of the filtration performance of cloth masks and common fabric materials against 20-1000 nm size particles. Annals of Occupational Hygiene 54(7):789-798. Rengasamy, S., E. Fisher, and R. E. Shaffer. 2010b. Evaluation of the survivability of MS2 viral aerosols deposited on filtering face piece respirator samples incorporatin g antimicrobial technologies. American Journal of Infection Control 38(1):9-17. Rissanen, S., I. Jousela, J. R. Jeong, and H. Rintamaki. 2008. Heat stress and bulkiness of chemical protective clothing impair performance of medical personnel in basic lifesaving tasks. Ergonomics 51(7):1011-1022. Roberge, M. R., M. R. Vojtko, R. J. Robe rge, R. J. Vojtko, and D. P. Landsittel. 2008. Wearing an N95 respirator concurrently with a powered air-purifying respirator: Effect on protection factor. Respiratory Care 53(12):1685-1690. Roberge, R. J. 2008. Evaluation of the rationale for concurrent use of N95 filtering facepiece respirators with loose-fitting powered air-purifying respirators during aerosol-generating medical procedures. American Journal of Infection Control 36(2):135-141. ———. 2009. Physiological burden asso ciated with the use of filtering facepiece respirators (N95 ma sks) during pregnancy. Journal of Women’s

Health 18(6):819-826.DESIGNING AND ENGINEERING EFFECTIVE PPE 111

Roberge, R. J., A. Coca, W. J. Williams, A. J. Palmiero, and J. B. Powell. 2010a. Surgical mask placement over N95 filtering facepiece respirators: Physiological effects on healthcare workers. Respirology 15(3):516-521. Roberge, R. J., A. Coca, W. J. Williams , J. B. Powell, and A. J. Palmiero. 2010b. Physiological im pact of the N95 filteri ng facepiece respirator on

healthcare workers. Respiratory Care 55(5):569-577.

———. 2010c. Reusable elastomeric air- purifying respirators: Physiologic impact on health care workers. American Journal of Infection Control 38(5):381-386. Salter, W. B., K. Kinney, W. H. Wallace, A. E. Lumley, B. K. Heimbuch, and

J. D. Wander. 2010. An alysis of residual chemicals on filtering facepiece respirators after decontamination. Journal of Occupational and Environmental Hygiene 7(8):437-445. Schumacher, J., J. Runte, A. Brinker, K. Prior, M. Heringlake, and W. Eichler. 2008. Respiratory protection during high-fidelity simulated resuscitation of casualties contaminated with chemical warfare agents. Anaesthesia 63(6):593-598. Schumacher, J., S. A. Gray, L. Weidelt, A. Brinker, K. Prior, and W. M. Stratling. 2009. Comparison of powered and conventional air-purifying respirators during simulated resuscitation of casualties contaminated with

hazardous substances. Emergency Medicine Journal 26(7):501-505. Shaffer, R., and S. Rengasamy. 2009. Re spiratory protection against airborne nanoparticles: A review. Journal of Nanoparticle Research 11(7):1661-1672. Tang, J. W., T. J. Liebner, B. A. Crav en, and G. S. Settles. 2009. A schlieren optical study of the human cough with and without wearing masks for

aerosol infection control. Journal of the Royal Society Interface 6(Suppl. 6):S727-S736. Udayasiri, R., J. Knott, D. T. D. Mc, J. Papson, F. Leow, and F. A. Hassan. 2007. Emergency department staff can effectively resuscitate in level C personal protective equipment. Emergency Medicine in Australasia 19(2):113-121. Viscusi, D., W. King, and R. Shaffer. 2007. Effect of deco ntamination on the filtration efficiency of two FFR models. Journal of the International Society for Respiratory Protection 24:93-107. Viscusi, D. J., M. Bergman, E. Sinkule, and R. E. Shaffer. 2009a. Evaluation of the filtration performance of 21 N95 filtering face piece respirators after prolonged storage. American Journal of Infection Control 37(5):381-386. Viscusi, D. J., M. S. Bergman, B. C. Eimer, and R. E. Shaffer. 2009b. Evaluation of five decontamination methods for filtering facepiece respirators. Annals of Occupational Hygiene 53(8):815-827. Vo, E., S. Rengasamy, and R. Shaffer. 2009. Development of a test system to evaluate procedures for decontamination of respirators containing viral droplets. Applied and Environmental Microbiology 75(23):7303-7309.112 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Vojtko, M. R., M. R. Roberge, R. J. Vojt ko, R. J. Roberge, an d D. P. Landsittel. 2008. Effect on breathing resistance of a surgical mask worn over a N95 filtering facepiece respirator. Journal of the International Society for Respiratory Protection 25:1-8. Wander, J., and B. Heimbuch. 2009. Challenge of N95 and P100 filtering facepiece respirators with par ticle containing viable H1N1. Pittsburgh, PA: National Institute for Occupational Safety and Health. Watson, C. M., M. C. McCrory, J. M. Duval-Arnould, and E. A. Hunt. 2009. Abstract P212: Simulated pediatric resuscitation during novel H1N1

influenza outbreak. Circulation 120:S1487-S1488. Watson, L., W. Sault, R. Gwyn, and P. R. Verbeek. 2008. The “delay effect” of donning a gown during cardiopulmonary resuscitation in a simulation

model. Canadian Journal of Emergency Medical Care 10(4):333-338. Wilkinson, I. J., D. Pisaniello, J. Ahmad, and S. Edwards. 2010. Evaluation of a large-scale quantitative respirator-fit testing program for healthcare workers: Survey results. Infection Control and Hospital Epidemiology 31(9):918-925. Wilson, J. A., H. P. Loveday, P. N. Hoffman, and R. J. Pratt. 2007. Uniform: An

evidence review of the microbiolo gical significance of uniforms and uniform policy in the prevention and control of healthcare-associated infections. Report to the Department of Health (England). Journal of Hospital Infection 66(4):301-307. Wines, M. P., A. Lamb, A. N. Argyro poulos, A. Caviezel, C. Gannicliffe, and D. Tolley. 2008. Blood splash injury: An underestimated risk in endourology. Journal of Endourology 22(6):1183-1187. Winter, S., J. H. Thomas, D. P. Stephens, and J. S. Davis. 2010. Particulate face masks for protection against airborne pathogens—one size does not fit all: An observational study. Critical Care and Resuscitation 12(1):24-27. Zhuang, Z., B. Bradtmiller, and R. E. Shaffer. 2007. New respirator fit test panels representing the curren t U.S. civilian work force. Journal of Occupational and Environmental Hygiene 4(9):647-659. Zhuang, Z., D. Groce, H. W. Ahlers, W. Iskander, D. Landsittel, S. Guffey, S. Benson, D. Viscusi, and R. E. Shaffe r. 2008. Correlation between respirator fit and respirator fit test panel cells by respirator size. Journal of Occupational and Environmental Hygiene 5(10):617-628.

## 4

Using PPE: Individual and Organizational Issues

Workers in a wide range of industries are required to wear personal protective equipment (PPE) to reduce or prevent exposures to hazardous chemicals, fire, particulates, or other health risks. As noted in Chapter 3, researchers, designers, and manufacturer s continue to look for improvements to the equipment that can reduce the physiological burdens, improve communication, and be more comfortable and less of an

encumbrance to wear. For healthcare personnel, the trade-offs of hazardous exposures with the challenges of donning, wearing, and doffing PPE often end up with healthcare pers onnel not fully adhering to PPE and infection control protocols. This chapter focuses on what has been learned about use of PPE by healthcare personnel and efforts to improve the safety culture in healthcare fac ilities. The chapter concludes with

recommendations for future research.

BACKGROUND AND CONTEXT FROM THE 2008 REPORT

Although healthcare personnel ofte n face hazardous working conditions with potential exposures to a vari ety of toxic and infectious agents, adherence to PPE protocols is often quite low. Observational studies and survey questionnaires of individual workers have looked at the reasons for the noncompliance and barriers to use, which often include the host of comfort and workability issues di scussed in Chapter 3. Few studies have tested interventions to improve adherence rates.

113114 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

The range of factors that impact PPE-related behaviors and compliance were organized in the 2008 Institute of Medicine (IOM) report and in other studies into three categories:

1. individual factors, such as knowledge, beliefs, attitudes, perception of risk, history, and sociodemographics;

2. environmental factors, including availability of equipment and negative-pressure rooms; and

3. organizational factors, such as management’s expectations andperformance feedback, workplace policies, and training and education programs.

Discussion in the 2008 report focused on the concerted efforts needed by individual healthcare person nel, managers, a nd institutions to improve the safety culture in health care facilities. This culture requires “an organization-wide dedication to the creation, implementation, evaluation, and maintenance of effective and current safety practices” (IOM, 2008, p. 8). Although organizational and cultural factors in the context of patient safety have received a great deal of attention in recent years, less

attention has been focused on healthcar e worker safety. In industrial settings, such as chemical and power plants, a focus on achieving high safety performance has been found to result from a sustained emphasis on safety factors at all levels of the organization: the individual level (e.g., attitudes, training), microorganizationa l level (e.g., management support, safety representatives, accountability), and macroorganizational level (e.g., communication, organization of technology, work processes)(Hofmann et al., 1995). Much can be learned from “high-reliability organizations” (e.g., nuclear power i ndustry; certain military operations, including aircraft carriers; commercial aviation), which are given that term because of their highly complex and hazardous missions and few safety-related failures. Characteristics of these organizations includecommitment to safety articulated from the highest level of the organization; resources, incentives, and re wards to carry out the commitment; continuous emphasis on safety; safety as the priority even at the expenseof production or efficiency; communication across all levels that is frequent and candid; openness about erro rs and issues as well as regular reporting; and valuing organizationa l learning and improvements (Gaba et al., 2003; Roberts, 1990; Rochlin, 1999; Singer et al., 2003; Weick et al., 1999). In many industrial work situations PPE use is considered a mandatory practice with a specific type of PPE or PPE ensemble re-USING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 115

quired whenever a certain job or task is performed. In health care, PPE use is often indicated for certain tasks, but often only under certain

conditions.Implementing a culture of safety can require changes in the organization’s policies, procedures, managerial actions and priorities, and resources dedicated to safety with access to effective safety equipment. Furthermore, the commitment to, and support of, safety is conveyed to workers at all levels through active an d sincere engagement by those in leadership positions who model, enc ourage, and enforce appropriate PPE use and safety. Finally, and importa ntly, individual accountability is key to improving and sustaining PPE use. The 2008 report identified four key factors in promoting a culture of safety within healthcare facilities; fact ors where research is still needed to improve PPE adherence are as follows:

1. Provide leadership, commitment, and role modeling for worker safety: Employees who perceive a strong organizationwide commitment to safety have b een found to be more than 2.5 times more likely to adhere to safety protocols than those who lack such perceptions (Gershon et al., 1995).

2. Emphasize healthcare worker education and training: The presence of safety education within a hospital or other healthcare facility demonstrates the organization’s commitment to safety and increases individual knowledge of safety practices.

3. Improve feedback and enforcement of PPE policies and use: The purpose of developing a positive and strong culture of safety in the workplace is to promote habitual safety practice. As noted in the IOM report,

Employees should feel uncomfortable when notwearing PPE during appropriate situations, and supervisors should reinforce the importance of PPE and enforce policie s so that noncompliance is the rare exception and not the rule. . . . Each healthcare employershould assume responsibility for taking an active role in facilitating, promoting, and requiring safety actions. Healthcare facilities need to foster and prom ote a strong culture of safety that includes a commitment to worker safety, ad equate access to safety equipment, and extensive training efforts that utilize protocols requiringspecific safety actions and detailing consequences for noncompliance. (IOM, 2008, p. 8)116 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

4. Clarify worksite practices and policies: Much remains to be learned about specific issues re lated to wearing PPE in the healthcare setting, particularly during an influenza pandemic. A concerted effort to identify best practices in infection control and

to disseminate this informati on to other healthcare facilitiescould increase worker and patient safety and have positive ramifications well beyond preparedness for an influenza pandemic.

As noted throughout the prior report, the use of PPE is only one component of promoting a strong safety culture in healthcare settings. Inaddition to PPE, the continuum of infection prevention and safety controls includes environmental and engi neering controls (e.g., number of air exchanges, availability of isola tion rooms with negative-pressure ventilation) and administrative or work practice controls (e.g., protocols to ensure early disease recognition, vacci nation policies, infection control guidelines for patients and visitors).

UPDATE ON RECENT RESEARCH

Organizational Factors Influencing Use of PPE

In healthcare organizations much of the emphasis on safety in the past decade has focused on patient safety (IOM, 2000). The relationshipbetween patient safety and worker safety is beginning to be further explored, and research continues into delineating the role of a number of factors in creating and sustaining a culture of safety in the healthcareworkplace (Lowe, 2008; Singer et al., 2009; Tucker et al., 2008). Highhazard industries, such as commerci al aviation and nuc lear power, are a major source for research on safety culture and provide useful information to mitigate hazard risk. For example, Lombardi and colleagues (2009) conducted a series of focus group discussions with 51 personnel— primarily from manufacturing, constr uction, and retail industries as well

as a few in health care—on the use of protective eyewear. The authors reported that risk perception, barriers to use of PPE, and enforcement and reinforcement are important safety cult ure concepts. Investigators furtherindicated that safety culture emerged as an important theme in encouraging PPE use, which included proper training, personal responsibility, peer pressure to use PPE, and approp riate and comfortable equipment. Supervisor and peer use of PPE was deemed important. As noted byUSING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 117

Lombardi and colleagues, “If the su pervisor doesn’t have [protective eyewear] on, no one else is going to wear them” (2009, p. 758). Positive reinforcement was seen as encourag ing; however, personnel often reported negative reinforcement by supervisors, such as being written up or threatened with job loss. Without enforcement, personnel questioned management’s sincerity about safety. A recent experimental study of social modeling of PPE use found a moderate positive correlation in the nu mber of participants wearing PPE (hearing protection in this study) and the number of safety model peers who wore the hearing protection (Olson et al., 2009). Safety leaders should consider peer influence as one important factor in the use of PPEas well as interventions such as training, adequate PPE supply, and positive reinforcement as a package.In another example of the impact of safety culture, Lowe (2008) surveyed 5,131 allied healthcare pers onnel, including emergency medical staff, community health personnel, and long-term care providers, about safety culture. Lowe reported that in the healthcare setting, teamwork, fair workplace processes, supportive and people-centered supervisors, leadership, a learning environment, and evidence that employers were working collaboratively to improve the work environment contributed to a culture that values safety. This br oader research base that examines safety culture influences and barriers should be further explored in order to inform the work of healthcare organizations. An in-depth review of Canada’s experience with severe acute respiratory syndrome (SARS) by the SARS Commission emphasized the importance of a robust safety culture in healthcare facilities and pointed to the need for close cooperation between infection control and occupational safety and health programs a nd personnel (Possamai, 2007). Although safety culture issues in health care go well beyond a discussion of PPE, they are important components of those discussions. Recent research on organizational factors that impact the use of PPE (Cavazza and Serpe, 2009; Lombardi et al., 2009; Olson et al., 2009) has reinforced many of the factors identified in the 2008 IOM report, including

• availability of and participation in training and refresher courses,

• supervisor use of PPE,

• peer use of PPE,

• organizational support for worker safety and health—the extent to which the company minimizes hazards and prioritizes safety goals. Support is also evidenced by senior manager support of118 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

safety practices and the level of encouragement for worker participation in health and safety discussions,

• positive reinforcement of individual compliance behavior, and

• negative reinforcement (e.g., verbal warnings).

Nichol and colleagues (2008) reported results from 177 nurses in 2 acute care hospitals in Canada. They found that compliance with PPE use was significantly related to organizational support for health and safety (however, no details were provided on what constituted organizational support). Other factors positively affecting the use of facial PPE included full-time employment status, more than 5 years of experience as a nurse, monthly or more frequent use of PPE, and belief in media coverageabout the risks of communicable diseases. The absence of job hindrances, such as heavy workloads, was an important contributor.Saint and colleagues (2009) conducted telephone and in-person interviews with 86 hospital staff in 14 U.S. hospitals about barriers to implementing evidence-based practices to prevent healthcare-associated

infections. The authors identified two types of personnel barriers: “active resisters” and “organizational constip ators.” Active resisters were identified as hospital staff who actively and openly opposed changes in practice. One person identified this gr oup as “entrenched culture.” Another type of active resister was one who had competing authorities on new practice implementation, such as hosp ital policy being in conflict with Centers for Disease Control and Prevention guidelines. Organizational constipators tended to be mid- to hi gh-level executives who prevented or delayed certain actions, thereby ac ting as barriers to evidence-based change implementation. They appeared to undercut changes and put their own interests ahead of those of orga nizations and patients. Strategies to

overcome these behaviors need to be identified and implemented. Additional studies point to the need for better training, equipment,and facilities. Ganczak and Szych (2007) conducted research on 601 surgical nurses in Poland and found that compliance with PPE varied considerably, ranging from 83 percent compliance with glove use to only 9 percent compliance with eye protectio n. Only 5 percent routinely used PPE when in contact with potentially infectious material. Compliance was higher among nurses who had received training in infection control. The most common reason reported for noncompliance was lack of PPE availability (37 percent). These findings related to adequate training were also found in a survey of 1,290 healthcare personnel as demonstrating the organization’s commitment to keep ing employees informed and up toUSING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 119

date on best practices (Yassi et al., 2007). Yassi and colleagues (2009) used questionnaires, workplace assessments, and discussion groups at aSouth African hospital to gather information from health and safety representatives and occupational health practitioners. Findings showed weaknesses in knowing how to use N95 respirators and handle sharps, as well as limited supplies and training related to practice procedures. Turnberg and investigators (2008) conducted a survey of 653 hospitalstaff in 5 medical centers in Washington state and found lack of knowledge by healthcare personnel about , and limited training on, recommended infection control practices and PPE usage, as well as limited resource support. Investigators indicate there is a clear need to identify and reduce barriers to safe practice. Recent research highlights the impor tance of the worker–task interface and work organization factors. Previous PPE research has often shown that physicians display poorer compliance than other categories of healthcare personnel. Although some recent data confirm this gradation (Manian and Ponzillo, 2007), other work suggests that these differencesmay be at least partially related to task assignments and the general organization of work (Chiang et al., 2008). Chiang and colleagues foundthat physicians complied better than nurses with PPE requirements during resuscitation activities in an intens ive care unit. In this study, thepoorer compliance of nurses was linked to the lack of specific task assignments, inadequate preparation for procedures, and the spatial characteristics and arrangement of the workspace. Lack of readily available PPE and time pressures continue to play a role in poor compliance (Shigayeva et al., 2007; Visentin et al., 2009). Other research shows that compliance may be more problematic in healthcare settings where staff vary on a day-to-day basis or rotate in and out of the setting (Trick et al., 2007). Job and task design, workgroup factors, supervisory practices, andother micro- and macro-work organization factors may also help to explain observed inconsistencies in compliance rates among healthcare personnel. These inconsistencies have been attributed previously to individual characteristics, such as job category, training level, job tenure, age, and even gender.

Individual Factors

Research published since 2007 on healthcare personnel and PPE shows that a number of individual factors continue to contribute to poor120 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

compliance and other safety-related outcomes. Three sets of factors deserve mention. First, studies continue to show knowledge gaps and training deficiencies among healthcare pers onnel with respect to proper PPEusage, modes of transmission, and other infection control topics. Research by Bryce and colleagues (2008) found that even though healthcarepersonnel may use appropriate PPE, they often do so incorrectly or incompletely. Examples include not doing a fit check after donning a respirator, continuing to use familiar device s regardless of fit test results, and not getting fit tested annually. Com posite compliance and comfort scores were assessed for use of N95 resp irators and eye protection (goggles, face shields, and other protective eyewear) among nurses, respiratory therapists, and other healthcare personnel at a tertiary care hospital that provides treatment for patients infected with tuberculosis (Bryce et al., 2008). For respirators, the composite compliance score was 86 percent offull compliance, and eye protection use was 74 percent of full compliance. No significant differences in compliance were observed for the three different models of N95 respirators used. The composite comfort score for N95 respirators was 68 percent of full comfort. For protectiveeyewear, the ability to see clearly was significantly and positively associated with both compliance and comfort. No association was reportedbetween compliance and comfort for either respirators or protective eyewear. Healthcare personnel reported that they “felt better protected” with N95 respirators than with face masks. Knowledge gaps also have been id entified with respect to properly removing PPE (Hitoto et al., 2009), diffe rentiating the protection levels offered by different types of PPE and PPE materials (Kanjirath et al., 2009), and having familiarity with newer protective devices (Ellison et al., 2007). This research highlights the fact that most PPE compliancebehaviors are not simple, discrete actions. Rather, they are sets or sequences of behaviors that can vary under different circumstances. Total and perfect compliance with PPE use is a daunting task under the best of

circumstances. Second, research continues to i ndicate that healthcare personnel often rely on their own personal assessments of risk in deciding whether or not to use PPE. Results from a study by Visentin and colleagues (2009)suggest that, despite administrative directives, emergency medical technicians may fail to use certain PPE when they are not convinced it is needed in particular situations. Shigayeva and colleagues (2007) produced similar findings with respect to barrier protection during the SARS outbreak in Canada. One study found that healthcare personnel may be-USING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 121

lieve they know more about PPE and in fection control than they actuallydo (Shigayeva et al., 2007). Studies on the willingness of healthcare providers to work during crises involvi ng infectious diseases have shown that having an adequate supply of PPE is an influential factor in being willing to respond and work (Balicer et al., 2010; Chaffee, 2009; Gershon et al., 2010a; Mackler et al., 2007; Wicker et al., 2009). Third, recent research shows that healthcare personnel still believe that PPE can interfere with the patie nt–provider relationship and/or reduce the quality of care. For example, concerns about PPE include decreases in the field of vision or reductions in manual dexterity(Daugherty et al., 2009; Ellison et al., 2007; Visentin et al., 2009). Fiftyfour healthcare personnel in a hospita l emergency department were asked to wear a respirator (P2, an N95 equivalent) for a 4-week period during the influenza season whenever they we re working within 1 meter of a patient with respiratory symptoms (Seale et al., 2009). During the first week, 24.1 percent of the participants wore the respirator “occasionally,” while 42.6 percent never wore the respirator. In week 2, only 3 of the 54 participants wore the respirator “on most shifts.” During weeks 3 and 4, only 1 healthcare worker wore the respirator “on most shifts.” By week 4, 70.4 percent of the healthcare personnel reported that they never wore the respirator. Their reasons were that it was hot, was difficult to breathe through, interfered with patient co mmunication, and had to be stored

somewhere between uses. Patient perceptions of PPE and its impact on provider behaviors is anarea of ongoing research. Recent findings are providing insights into patient expectations and preferences with respect to PPE. Routine use of PPE by dental care providers seems to be well accepted by patients andexpected as the norm (Molinari, 2010). Using a set of pictures of physicians with transparent face shields a nd traditional surgical masks, Forgie and colleagues (2009) asked parents and children (ages 4 to 10) which set of physicians they would prefer for patient care. Although 62 percent of parents thought their children would choose face shields, 59 percent of the children did not have a preference and found neither set to be frightening. A survey of dental patients found that face mask use was preferred by a majority of the patients (72 percent), with younger patients (< 46 years of age) more supportive of face mask use (McKenna et al., 2007).122 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Interventions to Improve Infection Control and/or PPE Compliance

Gammon and colleagues (2007) conducte d a literature review of research on healthcare worker compliance with standard/universal infection control precautions. They found suboptimal compliance in 24 studies that assessed compliance and only short-term improvements inthe 13 studies examining interventions (primarily training classes) to improve compliance. In most interv ention studies, compliance was monitored for only a few months after the intervention, and compliance often

returned to baseline levels within a relatively short time. For example, a study of emergency medical service s personnel found poor retention of donning and doffing procedures at a point approximately 6 months after the initial training (Northington et al., 2007). Since 2007, several training-related intervention studies have been done. Howard and colleagues (2009) tested a clean-practice protocol and found that it significantly improved hand decontamination and overall

infection control after 3 months. Howe ver, this was a small study without a control or comparison group. No further follow-up assessment was conducted to assess long-term maintenance. Hon and colleagues (2008) reported that an online infection control course adequately transferred knowledge regarding PPE selection and use. But again, no control group w as used, and the online course was not compared to other instructional modalities. In one better designed study, Trick and colleagues (2007) conducted a 3-year intervention study of hand hygiene and glove usage. Hygiene significantly improved in two of the three treatment hospitals compared with the control hospital. The best performing hospital also showed a re duced incidence of antimicrobialresistant bacteria infections. The third treatment hospital showed insignificant improvement. This hospital was a large, public teaching hospital. These recent studies tentatively suggest that multicomponent training interventions may be more effective than single-component efforts and that communications and convenient reminders placed throughout thework environment may boost compliance. Training and other interventions that make use of social-cognitive and other behavioral theories also appear to hold promise (Godin et al., 2008).USING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 123

Use of PPE by Home and Community

Healthcare Personnel

A segment of the healthcare workforce often overlooked in discussions on PPE and pandemic influenza pl anning is the more than 1.5 million home healthcare personnel and those working in community settings other than hospitals and large clini cs (e.g., schools, physician’s offices, long-term care settings) in the United States (Baron et al., 2009). Thesesettings do not generally offer the administrative and environmental safety controls that should be available in hospitals or other large healthcare facilities. A recent study examined factors relevant to the willingness and ability of home healthcare personnel to take care of their patients duringan influenza pandemic (Gershon et al., 2010b). Of the 384 home healthcare personnel responding to the questionnaire, 16 percent (57 workers) reported that their employer gave them a “respirator mask,” with 41workers reporting that they received training on how to use the equipment and 16 reporting that they had been fit tested on the equipment they were provided. When asked about wh ether they would be willing to provide care during a pandemic to their current patients, respiratory protection was a significant factor, with willingness to work being associated with “being confident that the mask would protect me” (51 percent) and “being given a respirator mask” (47 percent). Hinkin and colleagues (2008) con ducted a literature review and found poor compliance with standard precautions among community nurses. Employers must provide suitable facilities, sufficient supplies of PPE, and adequate training. The authors note that most research has beendone in hospitals, which has only limited applicability to other community settings.

SUMMARY OF PROGRESS

Research during the past several years reveals modest gains in understanding that self-protective behavi or in the healthcare settings involves a constellation of interacting and independent components. At a minimum, consideration should be given to the user, the device, the task, and the general work and organiza tional context. Daugherty and colleagues (2009) found that knowledge and task hindrances were related to poor compliance among critical care clin icians, with the authors concluding that organizational factors were more important than individual fac-124 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

tors in explaining PPE usage. The growing acknowledgment of contextual and organizational factors means that research on PPE and healthcare personnel is closing in on the larger body of occupational safety research, which increasingly emphasizes contextual and organizational factors in understanding occupational safety performance. Although there are clear gaps and deficiencies in our knowledge baseabout PPE usage in health care, existing knowledge is sufficient to recommend a four-pronged strategy fo r immediate implementation. The four elements are as follows: (1) deliberate planning and preparation at the leadership and organizational leve ls; (2) comprehensive training, including supervisors and managers; (3) widespread and convenient availability of appropriate PPE devices; and (4) accountability at all levels of the organization. In essence, there should be universal acknowledgment that PPE usage is an integral component of providing quality health care. As with other priorities, this aspect of healthcare delivery needs to be planned carefully at the organizati onal/institutional level, managers and

frontline workers alike need to unde rstand and accept their roles and responsibilities, and PPE usage needs to be as easy and convenient as possible. PPE should be factored into a ll decisions involving task design, staffing, and work assignments. Input from frontline workers should be used to facilitate planning and decision making and maximize acceptance. Environmental/engineering cont rols should be utilized wherever possible to control exposures, with PPE used as a supplement or alternative when environmental/engineering controls are not sufficient or feasible. The overall implementation of the PPE program should be monitored regularly, with the goals of continuous improvement, adoption of best practices, and accountability of both supervisor and worker.

FINDINGS AND RESEARCH NEEDS

This is an opportune time for research on promoting and enhancing healthcare worker safety and the use of PPE. As noted throughout the chapter, extensive workhas been done in recent years on improving patient safety. Efforts are needed to build on those efforts and identify the linkages between patient safety and worker safety, particularly with the use of PPE. Additionally, safety research conducted in other types of work settings has potential applicability to improving safety performance

and PPE use in health care. Furthermor e, much can be learned from recent experience by healthcare pers onnel and organizations during theUSING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 125

2009 H1N1 influenza, and exploring lessons learned can be instructive for moving research efforts forwar d. Increased knowledge and communication on the severity of the disease will also be important as decisions are made by organizations regardi ng PPE compliance. Box 4-1 highlights the committee’s findings in this area.The committee has identified the following research needs and recommendations. Some of these can and need to be addressed expeditiously; others will require longer-term efforts. The goals will be to identify and evaluate strategies to mitigate or ganizational and other barriers that limit the use of PPE by healthcare pe rsonnel and to identify incentives

and enforcement mechanisms to ensure ongoing organizational commitment and continuous improvement

. Efforts should be aimed across the spectrum of healthcare personnel a nd should consider language, educational, and cultural issues. Studies have examined barriers to PPE use; however, research gaps remain on identifying effective strategies for sustaining PPE use related to training, policies, and actions, including assessment of the knowledge, attitudes, and priorities of healthcare personnel and senior management about PPE. Research is needed on the following issues:

• PPE issues in health science school curriculums: Studies areneeded to determine the level of inclusion of contemporary concepts and applications regarding PPE in the curriculums of

BOX 4-1 Findings

• Self-protective behavior in healthcare settings involves a constellation of interacting and independent factors.

• Organizational and individual changes are complex, time consuming, and difficult to sustain.

• Personal protective equipment usage presents varied challenges across different types of healthcare settings.

• Existing knowledge is sufficient to begin to incorporate the following practices into PPE usage in health care: deliberate planning and preparation at the leadership a nd organizational levels; comprehensive training, including supervisors and managers; widespreadand convenient availability of appropriate PPE devices; and accountability at all levels of the organization.126 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

health science and allied health schools. These studies should include all levels of education where practice is a component.

Recommendations should be made for closing identified gaps and improving the development, content, and dissemination of PPE training materials.

• Healthcare worker safety culture: Recent efforts focused on patient safety should be expanded to examine the worker safetyclimate specific to the healthcare arena and PPE use. This includes examining the applicability to health care of researchfindings in the areas of patient safety, high-reliability organizations, high-hazard industries, a nd general industry. Lessons learned from the experience with 2009 H1N1 influenza could beinformative in identifying best practices, learning from organizations successful with PPE compliance by healthcare personnel aswell as from those with lower rates of compliance, and examining issues relevant to PPE policy and implementation relevant toboth large and small healthcare employers. To improve appropriate use of PPE, it will be vital to better understand the motivations and risk assessment process es used by healthcare personnel regarding use of and demand for PPE.

• Incentives and enforcement: Innovative approaches to incident reporting systems and other incen tive and enforcement actions need to be examined that promote PPE use by fostering a strong and positive culture of safety in the workplace and learning from

mistakes.

• Task and work organization: Efforts are needed to examine the contribution of task and work organization factors (how work processes are structured and managed) to PPE usage and other safe work practices in healthcare settings.

• Metrics: Similar to measures of the patient safety culture, metrics are needed to measure worker and organizational safety culture and use of PPE.

• Varying healthcare settings: In order to determine practice needs in different work settings, research is needed to examine and differentiate PPE policy and implementation strategies in large and small healthcare delivery settings.USING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 127

RECOMMENDATIONS

Recommendation: Explore Healthcare Safety Culture and Work Organization The National Institute for Occupational Safety and Health (NIOSH) and other relevant agencies, such as the Agency forHealthcare Research and Quality, and professional organizations should conduct research to better understand the role of safety culture and other behavioral and organizational factors on PPE usage in heal thcare settings. These efforts

should include

• conducting human factors and ergonomics research relevant to the design and organization of healthcare work tasks to improve wo rker safety by reducing hazardous exposures and effectively using PPE (e.g., reduce unnecessary PPE do nning and doffing),

• exploring the links between patient safety and healthcare worker safety and health that are relevant to the use of PPE, and

• identifying and evaluating strategies to mitigate organizational barriers that limit the use of PPE by healthcare personnel.

Recommendation: Identify and Disseminate Effective Leadership and Training Strategies and Other Interventions to Improve PPE UseNIOSH and other relevant agencies and professional organizations should support intervention effectiveness research toassess strategies, including innovative participatory approaches to training, for healthcare and supervisory staff at all levels to improve PPE usage and other related outcomes across the range of healthcare setti ngs. To identify best practices, efforts should be made to

• conduct observational studies of PPE usage by healthcare personnel in different types of work settings;

• develop, implement, and evaluate comprehensive leadership and training strategies and interventions that go beyond simple knowledge-based training;128 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

• design training interventions specifically for supervisory and managerial personnel in different types of healthcare settings;

• examine long-term practice change and safety culture implementation related to educational interventions;

• improve use and understanding of PPE by home and community healthcare personnel;

• develop assessment tools and metrics that take abroader approach to PPE and acknowledge the interaction of worker, task, and environmental factors;

and

• be informed by a lessons-learned summit on PPE useby healthcare personnel during the 2009 H1N1 experience.

REFERENCES

Balicer, R. D., D. J. Barne tt, C. B. Thompson, E. B. Hsu, C. L. Catlett, C. M. Watson, N. L. Semon, H. S. Gwon, and J. M. Links. 2010. Characterizing hospital workers’ willingness to report to duty in an influenza pandemic through threat- and efficacy-based assessment. BMC Public Health 10:436. Baron, S., K. McPhaul, S. Phillips, R. Gershon, and J. Lipscomb. 2009. Protecting home health care workers: A challenge to pandemic influenza preparedness planning. American Journal of Public Health 99(Suppl. 2):S301-S307. Bryce, E., L. Forrester, S. Scharf, and M. Eshghpour. 2008. What do healthcare workers think? A survey of facial protection equipment user preferences. Journal of Hospital Infection 68(3):241-247. Cavazza, N., and A. Serpe. 2009. Eff ects of safety climate on safety norm violations: Exploring the mediating role of attitudinal ambivalence toward personal protective equipment. Journal of Safety Research 40(4):277-283. Chaffee, M. 2009. Willingness of health ca re personnel to work in a disaster: An integrative review of the literature. Disaster Medicine and Public Health Preparedness 3(1):42-56. Chiang, W.-C., H.-C. Wang, S.-Y. Chen, L.-M. Chen, Y.-C. Yao, G. H.-M. Wu, P. C.-I. Ko, C.-W. Yang, M.-T. Tsai, C.-C. Hsai, C.-P. Su, S.-C. Chen, and M. H.-M. Ma. 2008. Lack of compliance with basic infection control measures during cardiopulmonary resuscitation—are we ready for another epidemic? Resuscitation 77(3):356-362. Daugherty, E. L., T. M. Perl, D. M. Needham, L. Rubinson, A. Bilderback, and C. S. Rand. 2009. The use of personal protective equipment for control ofUSING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 129

influenza among critical care clinicians: A survey study. Critical Care

Medicine 37(4):1210-1216. Ellison, A. M., M. Kotelchuck, and H. Bauchner. 2007. Standard precautions in the pediatric emergency department: Knowledge, attitudes, and behaviors of pediatric and emergency medicine residents. Pediatric Emergency Care 23(12):877-880. Forgie, S. E., J. Reitsma, D. Spady, B. Wright, and K. Stobart. 2009. The “fear factor” for surgical masks and face sh ields, as perceived by children and their parents. Pediatrics 124(4):e777-e781. Gaba, D. M., S. J. Singer, A. D. Sinaik o, J. D. Bowen, and A. P. Ciavarelli. 2003. Differences in safety climate between hospital personnel and naval

aviators. Human Factors: The Journal of the Human Factors and Ergonomics Society 45(2):173-185. Gammon, J., H. Morgan-Samuel, and D. Gould. 2007. A review of the evidence for suboptimal compliance of healthcare practitioners to standard/universal infection control precautions. Journal of Clinical Nursing 17(2):157-167. Ganczak, M., and Z. Szych. 2007. Surgi cal nurses and compliance with personal protective equipment. Journal of Hospital Infection 66(4):346-351. Gershon, R. R. M., D. Vlahov, S. A. Felknor, D. Vesley, P. C. Johnson, G. L. Delcios, and L. R. Murphy. 1995. Compliance with universal precautions among health care workers at three regional hospitals. American Journal of Infection Control 23(4):225-236. Gershon, R. R., L. A. Magda, K. A. Qureshi, H. E. Riley, E. Scanlon, M. T. Carney, R. J. Richards, and M. F. Sher man. 2010a. Factors associated with the ability and willingness of essential workers to report to duty during a pandemic. Journal of Occupational and Environmental Medicine 52(10):995-1003. Gershon, R. R. M., L. A. Magda, A. N. Canton, H. E. M. Riley, F. Wiggins, W. Young, and M. F. Sherman. 2010b. Pandemic-related ability and willingness in home healthcare workers. American Journal of Disaster

Medicine 5(1):15-26. Godin, G., A. Belanger-Gravel, M. Eccl es, and J. Grimshaw . 2008. Healthcare professionals’ intentions and behaviours: A systematic review of studies based on social cognitive theories. Implementation Science 3:36. Hinkin, J., J. Gammon, and J. Cutter. 2008. Review of personal protection equipment used in practice. British Journal of Community Nursing 13(1):14-19. Hitoto, H., A. Kouatchet, L. Dube, C. Le marie, A. Mercat, M. L. Joly-Guillou, and M. Eveillard. 2009. Factors affecting compliance with glove removal after contact with a patient or environment in four intensive care units. Journal of Hospital Infection 71(2):186-188. Hofmann, D. A., R. Jacobs, and F. Landy. 1995. High reliability process industries: Individual, micro, and macro organizational influences on safety performance. Journal of Safety Research 26(3):131-149.130 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Hon, C. Y., B. Gamage, E. A. Bryce, J. LoChang, A. Yassi, D. Maultsaid, and S. Yu. 2008. Personal protective equi pment in health care: Can online

infection control courses transfer knowledge and improve proper selection

and use? American Journal of Infection Control 36(10):e33-e37. Howard, D. P., C. Williams, S. Sen, A. Sh ah, J. Daurka, R. Bird, A. Loh, and A. Howard. 2009. A simple effective clean practice protocol significantly improves hand decontamination and inf ection control measures in the acute surgical setting. Infection 37(1):34-38. IOM (Institute of Medicine). 2000. To err is human: Building a safer health

system . Washington, DC: National Academy Press.

———. 2008. Preparing for an influenza pandemic: Personal protective equipment for healthcare workers . Washington, DC: The National

Academies Press. Kanjirath, P. P., A. E. Coplen, J. C. Chap man, M. C. Peters, and M. R. Inglehart. 2009. Effectiveness of gloves and infection control in dentistry: Student and provider perspectives. Journal of Dental Education 73(5):571-580. Lombardi, D. A., S. K. Verma, M. J. Brennan, and M. J. Perry. 2009. Factors influencing worker use of pe rsonal protective eyewear. Accident Analysis

and Prevention 41(4):755-762. Lowe, G. S. 2008. The role of healthcare work environments in shaping a safety

culture. Healthcare Quarterly 11(2):42-51. Mackler, N., W. Wilkerson, and S. Ci nti. 2007. Will first-responders show up for work during a pandemic? Lessons from a smallpox vaccination survey of paramedics. Disaster Management and Response 5(2):45-48. Manian, F. A., and J. J. Ponzillo. 2007. Compliance with routine use of gowns by healthcare workers (HCWs) and non-HCW visitors on entry into the rooms of patients under contact precautions. Infection Control and Hospital Epidemiology 28(3):337-340. McKenna, G., G. R. Lillywhite, and N. Maini. 2007. Patient preferences for dental clinical attire: A cross-sectional survey in a dental hospital. British

Dental Journal 203(12):681-685. Molinari, J. 2010, June 3. Dental community experience . PowerPoint presented at the IOM Workshop on Current Research Issu es—Personal Protective Equipment for Healthcare Workers to Prevent Tran smission of Pandemic Influenza and Other Viral Respiratory Infections, Washington, DC. http:// iom.edu/~/media/Files/Activity%20Files/PublicHealth/PPECurrentResearch

/2010-JUN-3/Molinari%20 -%20Panel%204.pdf (acce ssed March 14, 2011). Nichol, K., P. Bigelow, L. O’Brien-Pallas, A. McGeer, M. Manno, and D. L. Holness. 2008. The individual, environmental, and organizational factors that influence nurses’ use of facial protection to prevent occupational transmission of communicable respirat ory illness in acute care hospitals. American Journal of Infection Control 36(7):481-487. Northington, W. E., G. M. Mahoney, M. E. Hahn, J. Suyama, and D. Hostler. 2007. Training retention of level C personal protective equipment use byUSING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 131

emergency medical services personnel. Academic Emergency Medicine 14(10):846-849. Olson, R., A. Grosshuesch, S. Schmidt, M. Gray, and B. Wipfli. 2009. Observational learning and workplace safety: The effects of viewing the collective behavior of multiple social models on the use of personal protective equipment. Journal of Safety Research 40(5):383-387. Possamai, M. A. 2007. SARS and health worker safety: Lessons for influenza pandemic planning and response. HealthcarePapers 8(1):18-28. Roberts, K. H. 1990. Some characteris tics of one type of high reliability organization. Organization Science 1(2):160-176. Rochlin, G. I. 1999. Safe opera tion as a social construct. Ergonomics 42(11):1549-1560. Saint, S., C. P. Kowalski, J. Banaszak-Holl, J. Forman, L. Damschroder, and S. L. Krein. 2009. How active resisters and organizational constipators affect health care-acquired infection prevention efforts. Joint Commission Journal on Quality and Patient Safety 35(5):239-246. Seale, H., S. Corbett, D. E. Dwyer, and C. R. MacIntyre. 2009. Feasibility exercise to evaluate the use of pa rticulate respirators by emergency department staff during the 2007 influenza season. Infection Control and Hospital Epidemiology 30(7):710-712. Shigayeva, A., K. Green, J. M. Raboud, B. Henry, A. E. Simor, M. Vearncombe, D. Zoutman, M. Loeb, and A. McG eer. 2007. Factors associated with

critical-care healthcare workers’ adherence to recommended barrier precautions during the Toronto severe acute respiratory syndrome outbreak. Infection Control and Hospital Epidemiology 28(11):1275-1283. Singer, S. J., D. M. Gaba, J. J. Geppert, A. D. Sinaiko, S. K. Howard, and K. C. Park. 2003. The culture of safety: Results of an organization-wide survey in 15 california hospitals. Quality and Safety in Health Care 12(2):112-118. Singer, S., S. Lin, A. Falwell, D. Gaba, and L. Baker. 2009. Relationship of safety climate and safety performance in hospitals. Health Services

Research 44(2p1):399-421. Trick, W. E., M. O. Vernon, S. F. Welbel, P. Demarais, M. K. Hayden, and R. A. Weinstein. 2007. Multicenter intervention program to increase adherence to hand hygiene recommendations and glove use and to reduce

the incidence of antimicrobial resistance. Infection Control and Hospital Epidemiology 28(1):42-49. Tucker, A. L., S. J. Singer, J. E. Hayes, and A. Falwell. 2008. Front-line staff perspectives on opportunities for improving the safety and efficiency of hospital work systems. Health Services Research 43(5p2):1807-1829. Turnberg, W., W. Daniell, N. Seixas, T. Simpson, J. Van Buren, E. Lipkin, and J. Duchin. 2008. Appraisal of recommended respiratory infection control practices in primary care and emergency department settings. American Journal of Infection Control 36(4):268-275.132 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Visentin, L. M., S. J. Bondy, B. Schwartz, and L. J. Morrison. 2009. Use of personal protective equipment during infectious disease outbreak and nonoutbreak conditions: A survey of emergency medical technicians. Canadian Journal of Emergency Medicine 11(1):44-56. Weick, K. E., K. M. Sutcliffe, and D. Obstfeld. 1999. Organizing for high reliability: Processes of collective mindfulness. In Research in organizational

behavior . Vol. 1, edited by B. M. Staw and R. I. Sutton. Stanford, CA: Elsevier Science/JAI Press. Pp. 81-123. Wicker, S., H. F. Rabenau, and R. Gottschalk. 2009. [Influenza pandemic:

Would healthcare workers come to work ? An analysis of the ability and willingness to report to duty]. Bundesgesundheitsblatt Gesundheitsforschung

Gesundheitsschutz 52(8):862-869. Yassi, A., K. Lockhart, R. Copes, M. Kerr, M. Corbiere, E. Bryce, Q. Danyluk, D. Keen, S. Yu, C. Kidd, M. Fitzgerald, R. Thiessen, B. Gamage, D. Patrick, P. Bigelow, and S. Saunders. 2007. Determinants of healthcare workers’ compliance with infection control procedures. Healthcare Quarterly 10(1):44-52. Yassi, A., L. E. Nophale, L. Dybka, E. Bryce, W. Kruger, and J. Spiegel. 2009. Building capacity to secure healthier and safer working conditions for

healthcare workers: A South Af rican-Canadian collaboration. International Journal of Occupational and Environmental Health 15(4):360-369.

## 5

Policy Research and Implementation: Healthcare Systems, Standards,

and Certification

The emergence of 2009 H1N1 influenza and the ensuing dilemmas regarding personal protective equipm ent (PPE) for healthcare personnel highlighted challenges in healthcare de livery policy at institutional, state, regional, and national levels as well as policies about the relevant standards and certification processes. This chapter highlights issues regarding standards and policies for PPE for healthcare personnel and summarizes the experience and literature on the 2009 H1N1 pandemic relevant to PPE. The chapter also provides the committee’s recommendations on the next policy and regulatory steps needed to address the current challenges and improve PPE for healthcare personnel.

PPE STANDARDS AND CERTIFICATION

As described in Chapter 1 (with mo re detail provided in Box 5-1), a number of state and federal agencies and organizations have regulatory,standards-setting, and policy responsibilities regarding PPE for healthcare personnel. This section highlights several recent and ongoing efforts with potential impact on PPE for healthcare personnel, some of which require further attention and action.

Recent and Ongoing Changes to Standards and Regulations

Two recent regulatory changes im plemented by the Occupational Safety and Health Administration (OSHA) impact workplace access to

133134 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

PPE and voluntary consensus standards. A Final Rule, issued in November 2007, requires employers to provide PPE at no cost to their employees; this change took the burden of responsibility off the employees, who in some cases had been paying for their own protective equipment (29 Code of Federal Re gulations [CFR] 1910.132; OSHA, 2007). In September 2009, a Final Rule was promulgated to address various revisions of the voluntary consensus standards as they applied to several types ofPPE, including eye and face protection (29 CFR 1910.133), head protection (29 CFR 1910.135), and foot protection (29 CFR 1910.136; OSHA, 2009). Because many consensus standards are updated on a regular basis, the new OSHA regulations state that the employer needs to supply PPE that meets the current voluntary consensu s standard or either of the past two versions of that standard; thus employers do not have to purchase new PPE every time a consensus standard is revised. In October 2009, the National Ins titute for Occupational Safety and Health (NIOSH) proposed total inwa rd leakage (TIL) requirements for the certification of negative-pressure , tight-fitting respirators. The new regulation would require that half-facepiece, air-purifying respirators (including filtering facepiece respirators such as the N95 respirator) be fit tested to an anthropometrically selected panel of wearers. Respirators

would need to be able to achieve an acceptable fit to a wide range of faces. Two public meetings have b een held, and the docket for public comments closed in September 2010 (NIOSH, 2010a). NIOSH will evaluate the comments received and may then release a final standard. The goal is to improve the fit of respirators.In 2009, California became the first state in the nation to issue a standard requiring employers to protec t healthcare personnel from influenza and other viral respiratory diseases when it promulgated its aerosoltransmissible diseases standard (California Code of Regulations, 2010).

This standard uses Centers for Di sease Control and Prevention (CDC) guidelines and terminology to classify whether an aerosol-transmissible disease requires droplet precautions (use of face masks is permitted) or requires aerosol precautions (respiratory protection is required usingN95s at a minimum, and where aerosol-generating procedures are performed, a powered air-purifying respirator [PAPR] or greater level of protection is required) (Siegel et al., 2007). Thus, by adopting the CDCguidelines, healthcare employers in California would, for example, protect personnel against seasonal infl uenza using face masks, while exposures to measles virus would require respirators (N95s or greater). For novel or unknown pathogens (e.g., the 2009 H1N1 pandemic influenzaPOLICY RESEARCH AND IMPLEMENTATION 135

virus), the California standard sets the default protection level at airborne precautions where use of respirators would be required (California Code of Regulations, 2010).

Recent efforts have also focused on voluntary consensus standards development and on third-party c onformity assessment. ASTM International announced in April 2010 the establishment of a working group that will develop test methods to assess the effectiveness of antimicrobial gloves (ASTM International, 2010a). Additionally, a task group within

the subcommittee on consumer r ubber products has begun developing standards that focus on preventing the transfer of microorganisms through the use of antimicrobial agents (ASTM International, 2010c). Furthermore, an ASTM Internationa l subcommittee is focused on developing a product certification process for protective clothing and equipment that would include an option for third-party independent verification that the product met the relevant performance standards (ASTM International, 2010b).

BOX 5-1 Existing Standards, Guidelines, and Certification Processes

Food and Drug Administration (FDA) Medical device legislation beginning in 1937 and amended in 1976 makes the FDA the principal agency for clearing personal protective equipment (PPE) for use by healthcare personnel. PPE dev ices used in healthcare environments are considered medical devices and are regulated as either Class I or Class IIdevices. Class I devices are considered low risk to the user, and the basic requirement is that the manufacturer meet general standards for good manufacturing processes. Some Class I devices re quire that the manufacturer provide a 510(k) submission and demonstrate that the device meets specific voluntary standards and is substantively equivalent to a similar “predicate” device currentlyon the market. Examples of Class I devices that require a 510(k) submission include surgeon and examination gloves. Class II devices are considered intermediate risk and must be cleared through the 510(k) process before they are allowed to be marketed. Surgical gowns, face masks, and respirators are also categorized as Class II devices.

The FDA does not conduct tests on m edical devices; the agency reviews data submitted by manufacturers to demonstrate that the product has been tested (by the manufacturer or an i ndependent testing organization) to meet specified consensus standards. Respirators are required to be certified by the National Institute for Occupational Safety and Health (NIOSH) and must meet additional requirements for flammability and fluid protection. The FDA does not have any specific PPE requirements for pr otection against infectious diseases such as influenza. Therefore, ma sks and respirators have requirements that are

continued136 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

specifically geared for surgical room us e, not for protection against influenza or other viral respiratory diseases. The FDA has begun clearing such devices that make claims for antiviral protection. FDA regulations are designed to contro l the manufacture and sale of PPE. These regulations do not specifically a pply to employers or employees. Requirements regarding the use of PPE in the healthcare workplace are overseen by the Occupational Safety and Health Administ ration (OSHA), along with state and local agencies and employers.

National Institute for Occupational Safety and Health NIOSH is the principal governmental agency with responsibility for testing and certifying respirators. The National Personal Protective Technology Laboratory (NPPTL) establishes the testing requirements and performs tests on respirators submitted by manufacturers. Test ing and certification requirements areincorporated in the Code of Federal Regulations (42 CFR Part 84). Once a respirator is certified, the manufacturer is not required to resubmit the device for further testing unless modifications are made. NIOSH respirator testing and certificat ion requirements are specific to the type of respirator (e.g., air-purifying, se lf-contained breathing apparatus) and are not specific to the type of workplace wher e they will be used. There is no specific certification of respirators for healthcare personnel or for protection against infectious agents such as influenza. However, as discussed in Chapter 3, NPPTL staff

and other researchers have studied the performance of certified filters against nanoparticles that would be applicable to virons and also have conducted some research with antiviral filters. The NIOSH certification process does not evaluate or indicate the efficacy of antiviral tr eatments that may be applied to filters on certified respirators. NIOSH does not certify other forms of PPE, such as gloves and goggles, that would be relevant to the protection of healthcare personnel. NIOSH staff do participate in the development of voluntary consensus standards for other PPE and perform some research in these areas (IOM, 2010).

Occupational Safety and Health Administration OSHA has the primary responsibility for enforcing the pro per use of PPE inthe workplace, including in healthcare facilities. The two main regulations relevant to PPE use by healthca re personnel relevant to viral respiratory diseases are 29 CFR 1910.134, which governs th e use of respirators, and 29 CFR 1910.132, which governs the use of PPE other than resp irators. All respirators used by healthcare personnel must be N IOSH certified, and their use must be part of a respiratory protection program that includes attention to issues regarding medical clearance, fit testing (where applicable), and training. OSHA requires that other types of PPE meet specified voluntary consensus standards (in some cases—e.g., for eye and face protection—OSHA regulations include additional specifications as noted in 29 CFR 1910. 133). OSHA does not have specific standards covering the use of PPE by healthcare personnel and does not require that such PPE be cleared by the FDA.

Other Agencies and Organizations A number of other organizations also impact the use of PPE by healthcare personnel. The Centers for Disease Contro l and Prevention (CDC) provides in-POLICY RESEARCH AND IMPLEMENTATION 137

fection control guidance, including guidance on the use of respirators and masks by healthcare personnel for protection against influenza. During the 2009 H1N1 pandemic, the CDC infection control guidelines for healthcare personnel during seasonal influenza (which recommend droplet infection control precautions, e.g.,a face mask for non-aerosol–generating procedures) were changed to recommend airborne precautions involving the us e of respirators (respirators are recommended for aerosol-generating procedur es in both). However, some state health agencies or local healthcare facilities continued to recommend face masks consistent with seasonal influenza guidelines for the use of respirators and masks. In summer 2010, the CDC guidelines were revised to reflect the seasonal infection control precautions based on av ailability of an effective vaccine and updated knowledge about the risk of hospitalization and death from 2009 H1N1 influenza (CDC, 2010).The Joint Commission provides accreditation for many hospitals and a variety of other employers of healthcare pe rsonnel, such as home healthcare agencies. The use of PPE is included in the Joint Commission’s requirements for employers. State and local health agencies provi de guidance and licensing to employers of healthcare personnel. These agencies provide assistance to employers in the case of pandemic influenza that may include stockpiling of PPE and offering guidance on what type of PPE is appropriate for specific tasks. Standards development organizations (s uch as the American National Standards Institute and ASTM International) wo rk through professional organizations and standards development committees to develop voluntary consensus standards that specify testing methods and performance expectations. Standardsdevelopment committees include experts who represent manufacturers, employers, users, and government regulators. Each standards-development organization has its own rules about the balance of these committees and voting. Moststandards must be updated on a regular basis (e.g., 5 years) or they are withdrawn. Standards may specify whether PPE must be tested by an independent third party or whether the manufa cturer can perform the testing.

Moving Forward on PPE Standards and Certification

Many of the issues that require activity by regulatory agencies for worker protection regarding PPE use during pandemic influenza involve respirators and masks. Face (eye), hand, and body protection issues all involve barriers, such as goggles or face shields, gloves, and gowns, which should provide an adequate ba rrier against influenza transmission provided that they cover the exposed area. A major challenge in preventing influenza transmission continues to be clarifying the modes of transmission (Chapter 2). Occupational safety and health principles emphasize the im portance of protecting the worker, particularly when dealing with hazards of unknown severity or health138 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

impacts. For novel respiratory viru ses, the committee reiterates the

statements in the 2008 Institute of Medicine report regarding transmission of influenza A: “[w]ithout knowing the contributions of each of the possible route(s) of transmission, all routes must be considered probable and consequential” (IOM, 2008, p. 53). As reiterated throughout this repor t, PPE is one part of a comprehensive infection control program that includes engineering, administrative, and workplace controls, including vaccination. Because transmission of influenza occurs in the community a nd does not just occur in healthcare settings from patients and coworkers, vaccination—when effective—is a preventive measure that offers protection that is not tied to a specific workplace setting or on-the-job practices and equipment.

Face Masks and Face Shields

As discussed throughout this report, one of the most contentious issues regarding PPE to prevent influenza transmission is the use of masks versus respirators. Protection of healthcare personnel is paramount in these discussions. For employers, the issues to consider include purchase and training costs. As discussed in Chapter 3, more research is needed to determine the extent and nature of the protection that face masks and face shields can provide against viral respiratory disease transmission; arole in providing contact and droplet spray has been suggested but remains unclear. As information becomes available that clarifies the PPE role that face masks and face shields play in preventing transmission of viral respiratory diseases, voluntary co nsensus standards and certification processes will need to be developed, implemented, and refined so that healthcare personnel and other consumers will have information on the effectiveness of these products. OSHA’s respiratory protection standard (29 CFR 1910.134) includes requirements for the selection, use, and maintenance of respirators.Since face masks are not respirators, they are not covered by this standard. OSHA general PPE standard ( 29 CFR 1910.132) applies to face shields and face masks; however, specific performance standards or other design or performance criteria for these products are not included in this OSHA regulation. To move forward with this issue, OSHA could work with other agencies and organizations to identify relevant voluntary consensus standard requirements an d consider if selection, maintenance, storage, and inspection requirements for face masks and facePOLICY RESEARCH AND IMPLEMENTATION 139

shields should be detailed in OSHA re gulations to provide further protection for healthcare personnel.

Respirators

Fit and fit testing Several significant policy and regulatory issues exist regarding respirator fit and fit testing that could impact healthcare worker safety and health in the midst of an influenza pandemic or an outbreak ofa novel viral respiratory disease. During an emergency situation, employers may run out of respirators that have been fit tested on personneland may be unable to obtain additional supplies from the same manufacturer or an emergency stockpile. If supplies of other types of respirators are available, then OSHA requirements stipulate the need for repeat fit testing with the new type of respirat or to ensure proper fit and protection (29 CFR 1910.134). The challenge dur ing an emergency situation could be the need to do fit testing for larg e numbers of workers in a short period of time. Therefore, a user seal check or other quick method of determining the fit of a respirator n eeds to be developed and recommended by NIOSH and/or OSHA as a temporary measure to be used during emergencies until the required fit testing can be completed.A second issue is that the current NIOSH respirator certification program has no requirement for a TIL test for filtering facepiece respirators(e.g., many N95 respirators). Therefore, a respirator may be NIOSH certified for filtration efficiency, but have poor-fitting characteristics and be unable to fit a large number of work ers. When health agencies or employers stockpile respirators, they may choose devices based on cost and availability but may not have the knowledge about how well the device will fit their population. This issue became widely recognized during the 2009 H1N1 pandemic when a California stockpile of respirators was used and healthcare personnel could not obtain a satisfactory fit (NIOSH,2010b). The proposed respirator TIL regulations would assist in addressing this issue and provide empl oyers and workers with better fitting respirators.

PAPRs During an influenza pandemic, some healthcare personnel whodo not normally wear respirators may need to wear them. These individuals are unlikely to be able to obtain a respirator fit test in a timely manner. In addition, some individuals may have facial hair or other facial140 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

features that do not allow them to be f itted adequately to a typical N95 or other tight-fitting respirator. These individuals would need to be assigneda loose-fitting PAPR. These types of respirators provide forced-flow filtered air but currently have high noise levels that are not conducive to healthcare tasks and patient interac tions, including speech perception and listening to chest sounds. Efforts ar e underway by the National Personal Protective Technology Laboratory (N PPTL) to develop regulations for testing and approving lower flow PA PRs that would provide acceptable respiratory protection in a healthcare environment but emit less noise and thus be more useful for healthcare work that requires communication with patients. Expediting these efforts is critical to improving PPE for healthcare personnel.

Aerosol-transmissible disease standard As noted above, California adopted an aerosol-transmissible diseases standard in 2009 (California Code of Regulations, 2010). The st andard includes a list of diseases and pathogens that require airborne pr ecautions as outlined by CDC, including “novel or unknown pathogens” (C alifornia Code of Regulations,2010). The scope of airborne precaution measures includes the requirement for “at least the use of an N95 respirator” (Jensen et al., 2005). During the 2009 H1N1 pandemic, the California standard was the only workplace standard in the United States that required a mandatory level of worker protection to be provided to healthcare personnel. Other state and local health departments had access to the CDC and OSHA guidance, but practices at healthcare fa cilities varied in whether and when they followed airborne or droplet infection control precautions. In May 2010, OSHA issued a Federal Register notice requesting information on occupational exposure to infectious ag ents in health care and related settings (e.g., laboratories, medical examiner offices) (OSHA, 2010).OSHA needs to work toward the development of an aerosoltransmissible diseases standard that would provide ade quate protection for healthcare personnel and that woul d, in situations of unknown or novel pathogens, default to providing full respiratory protection until more was known about the lethality or contagiousness of the disease.

Other regulatory issues To gain approval for marketing as a medicaldevice, the Food and Drug Administration (FDA) stipulates that the respirators must be NIOSH certified and meet flammability and fluid pro-POLICY RESEARCH AND IMPLEMENTATION 141

tection standards; these standards are not relevant for most situations inwhich workers must be protected from influenza. During the recent pandemic, the FDA identified non-cleared respirators that would be acceptable for healthcare personnel. To alleviat e this issue for future crises, theFDA could consider a separate 510(k) requirement that allows manufacturers to market any appropriate NIOSH-certified respirator during an influenza pandemic. This would rapidly allow all certified respirators to be available for use by healthcare personnel.

LESSONS LEARNED FROM 2009 H1N1 POLICIES

RELEVANT TO PPE FOR HEALTHCARE PERSONNEL

The arrival of novel H1N1 influenza A in 2009 was accompanied bya number of policy questions relevant to PPE. The lack of precise information about the modes of influenza transmission, the contagiousness, the virulence of novel H1N1 influenza A, the at-risk population, and the efficacy of different devices in preven ting transmission led to a variety of

recommendations at different time s by federal and local government public health agencies. Delayed and/or disparate recommendations often led to confusion among healthcare pe rsonnel and their employers, who had to decide what to tell personnel about what type of PPE to wear and when. In addition, little research was available to guide health system officials in making decisions about the quantities of various types of PPE needed to protect their workforce. A major problem encountered was a slow response in tailoring recomme ndations as more knowledge about virulence and affected populations became available. The committee looked to two examples of response to 2009 H1N1 (New York City [NYC] and Northern Virginia), with information provided by committee members, works hop speakers, and individual interviews. Northern Virginia hospitals, for example, developed standardized infection control policies that included a definition of high-risk workers. To address supply chain shortfalls, the 14 member hospitals of the Northern Virginia Hospital Allianc e (NVHA) agreed to follow CDC respirator guidelines until no longer practical. As a matter of practice, hospitals modified the CDC guidelines in regards to PPE requirements for non-high-risk workers, especially as it became clear in fall 2009 that the

virulence of 2009 H1N1 was similar to seasonal influenza viruses (Personal communication, Zachary Corrigan, NVHA, 2010).142 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

In NYC, the fire department emph asized the need for paramedics and emergency medical technicians to u se N95 respirators as they work in the pre-hospital environment where environmental controls do not exist. When the H1N1 virus first emerged, the NYC Department of Health and Mental Hygiene and the New York State department of health initially recommended N95 respirators but then scaled back the recommendations

to face masks to be consistent with seasonal influenza recommendations

once it was determined that the virule nce and transmissibility were similar to seasonal influenza. However, once CDC published its interim infection control guidance in October 2009, the New York city and state departments of health revised their guidance to be consistent with the federal recommendations for N95 resp irators. In anticipation of the second wave of H1N1 returning in Fa ll 2009, the city health department, working with the NYC Office of Emergency Manage ment, convened regular healthcare emergency planning meetings to improve hospital and primary care preparedness. The NYC health department also put in place a program to provide additional N95 respirators from a local government stockpile for healthcare facilities e xperiencing supply shortages during the 2009 pandemic (Personal communication, David Prezant, New York City Fire Department).

PPE Policies During the Novel H1N1 Influenza Pandemic

During the initial phase of the 2009 H1N1 influenza pandemic, infection control guidelines from some of the major public health organizations differed, primarily as related to respiratory protection (Table 5-1). The World Health Organization (WHO) recommended standard anddroplet precautions (including a face mask, a gown, gloves, eye protection, and hand hygiene) for those working in direct contact with patients, and additional precautions for aerosol -generating procedures, including wearing a facial particulate resp irator (WHO, 2009). The WHO recommendations took into account the need for sustainability in a variety of countries and encouraged each country to issue its own guidelines. CDCrecommended a fit tested, disposable N95 respirator or better for healthcare personnel who enter the rooms of patients in isolation with suspected or confirmed novel H1N1 influenza (CDC, 2009b). For emergency medical responders, CDC recommended a fit tested, disposable N95 respirator for those pers onnel “who are in close contact” with patients with confirmed or suspected 2009 H1N1, for personnel “en-POLICY RESEARCH AND IMPLEMENTATION 143

gaged in aerosol generating activities,” and for personnel involved in the “interfacility tran sfer” of patients w ith suspected or confirmed 2009 H1N1(CDC, 2009a). The Public Health Agency of Canada used a tiered approach that recommended N95 use for aerosol-generating procedures with direct patient contact only (PHAC, 2009a,b,c,d).

Overview of Recent Policy Research

Research on healthcare policies and their implementation is lacking as it pertains to the use of PPE. Given the many PPE policy issues during

TABLE 5-1 Overview of 2009–2010 H1N1 Policies and Practices Regarding Personal Protective Equipment and H1N1 Influenza

CDC

Guidance

4/29/09

Novel

Pandemic

Influenza CDC

Guidance

10/15/09

Novel

Pandemic

Influenza CDC

Guidance for

Seasonal

Influenza

9/20/10 WHO

Guidance Public

Health Agency of

Canada

Guidance

for Novel

H1N1

Recommended

level of infectio n control precautions Standard

and contact precautions and eye protection Standard and droplet precautions Adhere to

standard and droplet precautions Standard and droplet precautions Tiered approach

Recommended respiratory

PPE NIOSHcertified

N95 respirator NIOSHcertified

N95 respirator Face mask except for

aerosolgenerating procedures,

use N95 or

better Face mask except for

aerosolgenerating procedures Face mask except for

aerosolgenerating procedures

Did the respiratory PPE

recommendation differ by

work task? Yes—

direct care

versus indirect patient

contact Yes—

direct care

versus indirect patient

contact Yes—

direct care

versusaerosolgenerating procedures Yes Yes

NOTE: CDC = Centers for Disease Control and Prevention; NIOSH = National Institute for Occupational Safety and Health; PPE = personal protective equipment; WHO = World Health Organization. SOURCES: CDC (2009a,b); PHAC (2009a,b,c,d); WHO (2009).144 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

the initial stages of 2009 H1N1, more papers are likely to be forthcoming

as healthcare institutions document their experiences and researchers have the opportunity to publish their findings. This section reviews some of the research and summaries pub lished since 2007 regarding policies on PPE use. Because PPE is one part of infection control strategies, some of the communications and emergency planning aspects are part of a larger discussion on pandemic planning (see, e.g., Daugherty et al., 2010).

Supplies of PPE

One issue faced during 2009 H1N1 was ensuring that healthcare facilities had adequate supplies of PPE a nd other supplies. As noted in an article by Rebmann and Wagner (2009), less than a month after the first case of laboratory-confirmed novel H1N1 was reported in the United States, CDC had deployed 25 percent of the Strategic National Stockpile(SNS) of N95 respirators. A focus group study of infection control specialists identified issues faced in the first months of the pandemic (Rebmann and Wagner, 2009). Supply issues of prime concern included running out of respirators or certain sizes of respirators and facing back orders early in the pandemic. Similar supply issues were seen in the early months of the pandemic in Australia , with concerns noted about the amount of time and quantity of PPE supplies retrieved from the SNS (Eizenberg, 2009). Determining the quantities of PPE required was the focus of a report by Murray and colleagues (2010) that ex amined the use of facial protective equipment from late June through mid-December 2009 in three Vancouver, Canada, hospitals. During that tim e, 865 patients with suspected cases of H1N1 influenza were admitted, with 149 patients having laboratoryconfirmed H1N1 influenza infection; 134,281 masks and 173,145 N95respirators were used. Comparisons were made of the number of respirators, masks, and protective eyewear used within the same period in 2008, with increases of 107 percent in the number of respirators, 70 percent in the number of eyewear, and 196 percent in the number of masks. The authors reported that the Ministry of Health plans for pandemic influenza called for hospitals to have a 10-week supply of PPE equipment, but they did not account for increases in the supplies that would be needed. Two reports provide detailed descriptions of the planning process used by the U.S. Department of Veterans Affairs to determine the quanti-POLICY RESEARCH AND IMPLEMENTATION 145

ties and types of PPE needed to r espond to pandemic influenza. This process included considerations of many factors that weighed into those decisions, such as the anticipated number of patients, the number of healthcare worker contacts per patient, PPE needs, and cost (Koenig et al., 2007; Radonovich et al., 2009). The Northern Virginia Regional Hospital Coordinating Center, the operational arm of the Northern Vi rginia Hospital Allliance Emergency Preparedness and Response Program, reported that member hospitals developed regional stockpiles of resp iratory PPE based on a risk stratification of their personnel. They used OSHA’s occupational risk pyramid for pandemic influenza to estimate the numbers of personnel at higher

risk and then used a formula that cons idered the size of the facility and the number of providers to get final estimates for distribution. Suppliesof PAPRs, reusable elastomeric N95 respirators, disposable N95 respirators, and surgical masks were provided to member hospitals from regional stockpiles (Personal communication, Zachary Corrigan, NVHA, 2010). Several studies have made initial attempts to estimate the quantity of PPE needed, but further work on predictive models is needed. Swaminathan and colleagues (2007) conducted a simulation study in nine Australian hospital emergency de partments designed to evaluate the number of contacts between patients and healthcare personnel and to determine the number of types of PPE that would be required. Compliance of healthcare personnel in using the appropriate PPE was also examined. The study focused on only the first 6 hours of contact 1 with a suspected case. The researchers reported an aver age of 12 close contacts, with 19exposures per “case,” and estimated that approximately 20 N95 respirators, 22 gowns, and 25 gloves would have been required to protect healthcare personnel during the first 6 hours of care. Given the rates of compliance noted in this study, up to 40 percent of healthcare personnel may have required post-exposure prophylaxis. This study provides some initial objective evidence regarding the numbers of PPE sets that might be required, but it was limited by its short duration of only 6 hours and by the simulation of a patient who was not critically ill. Similar types of

research that extend the observation duration and simulate more severe illness would be helpful in estimating PPE requirements. In Japan, Hashikura and Kizu (2009) used the severe acute respiratory syndrome outbreak as a paradigm for PPE use. The researchers re1 Close contact was defined as be ing within 1 meter of a patient or within an isolation

room.146 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

viewed the literature and the guidelines on PPE use from many countries, and then estimated the numbers of PPE ensembles that would be required during a pandemic, using information on the type of pandemic, type of healthcare worker, and numbers of PPE ensembles per classification per day. They estimated (using OSHA recommendations) that four sets (N95, gloves, gowns, and goggles) would be used per day by high-risk healthcare personnel, who are define d as persons performing high-risk procedures, such as intubations, suctioning, and manipulating respiratory equipment. Two sets of appropriate PPE was the estimate for mediumand low-risk healthcare personnel (thi s included an N95 respirator for medium-risk and a surgical mask for low-risk workers). The researchers also estimated that two surgical ma sks would be required for every inpatient and one for every out-patient. They then estimated the total numbers of PPE required for a 300-bed ho spital during an 8-week pandemic— nearly 20,000 N95 respirators, 122,000 surgical masks, 21,000 goggles and gowns, and 172,000 pairs of gl oves would be needed. This study provides an initial start on the question of estimated quantities, but is theoretical and based only on publis hed recommendation guidelines. The methodology is logical, but needs to be validated. Data on actual use of PPE by a hospital is needed to compare the accuracy of the predictions.A study comparing single-use versus reusable surgical gowns highlights another area of discussion regarding costs and quantity of supplies. Baykasoglu and colleagues (2009) conducted a cost/benefit study that considered a number of factors, in cluding laundry, sterilization, and waste disposal costs, as well as the extent of protection and functionality. The study determined that the single-use sets had higher benefits, but when costs were considered, the more expensive reusable sets had higher

benefit/cost ratios. This area of r esearch and modeling could provide practical insights, particularly as effective decontamination processes

become defined.



### H1N1 Experiences with Use of PPE by Healthcare Personnel

Evidence of transmission to healthcare personnel was reported during the pandemic, indicating the need for comprehensive PPE policies. Santos and colleagues (2010) examined an NYC hospital’s absentee records for 3 months (April through June 2009) and compared the results with the same periods in 2007 and 2008. The researchers found that healthcare personnel in the adult a nd pediatric emergency departmentsPOLICY RESEARCH AND IMPLEMENTATION 147

had the highest infection rate per de partment. The peak of influenza in healthcare personnel was noted to have lagged slightly behind the peak in the general public. The literature on policies put in place during 2009 H1N1 will likely grow in the next several years. At this point only a few articles have been published that focus on PPE use durin g the initial phases of H1N1. Early in the epidemic, Perez-Padilla and colleagues (2009) reported their experience in Mexico City. They focused on the cl inical presentation of H1N1, but also noted information on the transmission of disease tohealthcare personnel. The report noted that 22 of 190 workers who became infected had been involved in caring for the first 3 H1N1 patients in a series of 18 patients admitted during the first month of the pandemic in spring 2009. These included 19 ou t of 104 emergency department workers who had been within 2 meters of a patient or had direct contact with a patient. These 22 workers had mild to moderate disease, and none required hospitalization. The hospital th en instituted strict infection control measures, including N95s, gowns, gloves, goggles, and hand hygiene, and noted that no additional workers became ill with influenzalike illness, although 26 did have vari ed respiratory symptoms and were

treated with oseltamavir. Focus group discussions with a group of infection preventionists in the United States pointed out the logis tical issues that were faced in the first months of the pandemic in trying to fit test a large number of staff (Rebmann and Wagner, 2009) as well as the challenges in determining whether and when to recommend the use of face masks or respirators. Of the focus group participants, approxi mately one-third said that PPE-use guidelines changed at their facilities about halfway through the event. A survey of healthcare epidemiol ogists, administrators, and other members of the Society for Healthcare Epidemiology of America in May 2009 found that 19.3 percent of respondents strongly agreed and 52.7 percent agreed that “the recomme ndation for airborne precautions forsuspected H1N1 cases was appropriate at the beginning of the H1N1 crisis” at his or her institution (Lautenb ach et al., 2010, p. 3). When asked whether airborne precautions for suspected cases were appropriate throughout the H1N1 crisis, 7.5 percent strongly agreed and 17.5 percent agreed. Supplies of N95s were a c oncern with some respondents; 16.9 percent disagreed and 8.8 percent strongly disagreed with the statement that “N95 masks were readily available throughout the H1N1 crisis at my institution” (Lautenbach et al., 2010, p. 3).148 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Changes in PPE guidelines were an issue for healthcare personnel in Australia, as identified in a questionnaire and focus group study (Corley et al., 2010). Healthcare staff repor ted confusion over the changing requirements and noted that this led to staff feeling “undervalued” and “unprotected.” Discomfort in wearing a respirator for a 12-hour shift with maybe a 1- to 1.5-hour break was noted as a challenge, as was the considerable amount of time spent on donning and doffing PPE.

The need to reinforce education and communication about PPE and other infection control processes for pre-hospital healthcare personnel, including paramedics, was noted as one of the key lessons learned in the H1N1 pandemic by a group reviewing the response in Victoria, Australia (Smith et al., 2009).Prior to the 2009 H1N1 pandemic, simulations and other planning efforts included a focus on PPE issues and policies. Phin and colleagues(2009) assessed a 24-hour simulation exercise in England and highlighted PPE cost and procurement issues as well as issues involving the storage of PPE supplies and increases in the amount of trash generated. The exercise noted unnecessary staff m ovement related to delivery of supplies and provision of services that also impacted PPE use. A review of emergency plans in three Ontario hospitals noted a number of PPE issues, including addressing fit testing requirements; regular training, including practice drills; stockpiling, warehousing, and inventory management; and storage and maintenance of PPE (Amaratunga et al., 2007). An extensive planning effort by a task force of the European Society of Intensive Care Medicine addressed a range of policy issues related topandemic planning, including the need to develop protocols for safe performance of procedures (including aerosol-generating procedures) that might put personnel at risk (Sprung et al., 2010). Training regarding PPE and an organizational culture that promotes safety were also discussed.

SUMMARY OF PROGRESS

Preparations and implementation of infection control plans for 2009 H1N1 influenza brought into sharp focus the efforts by healthcare professionals, emergency planners, professional associations, healthcare facilities, policy makers, government agen cies, labor unions, and others to address PPE policies and logistics. Artic les continue to be published on the recent experience and the challenges and successes in providing face masks, respirators, and other PPE to healthcare personnel. As lessonsPOLICY RESEARCH AND IMPLEMENTATION 149

learned during that experience continue to add to the body of knowledge, incorporating this information into research, policy, and practice efforts will be important. In the initial phases of an epidemic or pandemic— when there are many unknowns about the virus or agent—one of the challenges is to determine PPE policy and then to adapt those policies asinformation is gained on the severity, transmission, and nature of the disease with an emphasis on communicating those changes. Standardssetting, regulatory, training, and research efforts continue to move toward improved respiratory protection, and recent work has begun to focus on the specifics of how to tailor PPE devices and PPE training to address the specific needs of healthcare personnel.

FINDINGS AND RESEARCH NEEDS

This chapter has provided an overview of the many policy and regulatory issues relevant to developing and improving PPE for healthcare personnel. The committee’s findings (outlined in Box 5-2) and research needs and recommendations (below) point to the many opportunities available, making now a particularly urgent time to build on recent experiences and needs and to move forward with the policy research and regulatory changes that will improve protection for healthcare personnel. The committee highlights the following research needs:

• Lessons learned from the 2009 H1N1 policies relevant to

PPE: Case studies of the implementation of 2009 H1N1 PPErelated policies should be ga thered and evaluated.

• PPE supply estimates: Studies are needed that compare theoretical models of estimating quantities of PPE for emergency preparedness with recent experience to inform future public health planning.

• Cost-effectiveness research: Research is needed into costeffectiveness issues relevant to PPE, including issues of disposable and reusable equipment.

• Impact of public health guidance: Prospective research efforts should examine the impact of public health guidance on PPE compliance by state, local, and health system policy; clinical practice; and costs.150 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

BOX 5-2 Findings

• Public health guidance regarding personal protective equipment (PPE) use for protection from novel viral respiratory infections needs to be timely, flexible, and consistent and should require the appropriate PPE

based on what is known at the time about transmission and virulence.

• Public health policy regarding PPE use for healthcare personnel’s protection from viral respiratory infections needs to recognize that transmission occurs in the community from family and friends as well as in the work environment from patients an d coworkers. Recognition of this fact is the foundation for an aggressi ve vaccination program for healthcare personnel.

RECOMMENDATIONS

Recommendation: Move Forward on Better Fitting RespiratorsNPPTL should continue rulemaking processes for TIL regulations that require respirators to meet fit criteria. To improve consumer and purchaser information on fit capabilities, NIOSH should establish a website to disseminate fit test results for specific respirat or models on an anthropometric (NIOSH) test panel, where such data exist.

Recommendation: Clarify PPE Guidelines for Outbreaks of Novel Viral Respiratory Infections NIOSH, other CDC divisions, OSHA, and other public health agencies should develop a coordinated process to make, announce, and revise consistent guidelines regarding the use of PPE to be worn by healthcare personnel during a verified, sustained national/international outbreak of a novel viral respiratory infection. The agencies should tailor theirguidance in a timely and coordinated manner as the virulence, contagiousness, and aff ected populations are further

characterized.

Recommendation: Standards and Certific ation for Face Masks

and Face Shields NIOSH, OSHA, and standards- development organizations should develop the standards and certification processesPOLICY RESEARCH AND IMPLEMENTATION 151

needed to assess the performa nce of face masks and faceshields as PPE. The development of standards and certification processes should be guid ed by research regarding their efficacy as PPE.

• OSHA and CDC should clarify that face masks are governed by the general PPE standard (29 CFR1910.132) and not by the respiratory protection standard (29 CFR 1910.134).

• NIOSH should work with other agencies and standardssetting organizations to develop voluntary consensus standards and independent third-party testing and certification processes for face shields and face masks, with specific tests fo r assessing prevention of transmission of viral respiratory diseases.

Recommendation: Establish PPE Regulations for Healthcare

Personnel CDC, including NIOSH, and OSHA should develop andpromulgate guidelines and regulations that are consistent regarding the use of PPE by healthcare personnel for influenza and other viral respiratory diseases:

• To assist employers in complying with the OSHA PPE standard, OSHA should specify the voluntary

consensus standards that a re required to be met for non-respirator PPE (e.g., gowns, gloves, face shields, face masks) in the event of influenza and other viral respiratory diseases.

• OSHA, with input from CDC and other agencies and organizations, should work toward promulgating an

aerosol-transmissible diseases standard that would include prevention of the transmission of influenza and other viral respiratory diseases.

As noted throughout the chapters, this report is an update of a prior IOM report. In surveying the landscap e of research that has been conducted since the 2008 report and even in the wake of the 2009 H1N1 influenza pandemic, the committee was struck by the lack of urgency in addressing the basic, applied, and clinical research questions that, if an-152 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

swered, would go a long way toward improving preparedness and prevention against future influenza epidemics and pandemics and outbreaks of other respiratory viral agents. Looking back is often a way to propel efforts in moving forward. The comm ittee hopes that this review will jumpstart and strengthen improvement s in PPE for healthcare personnel that could be relevant to a range of viral respiratory diseases.

REFERENCE S

Amaratunga, C. A., T. L. O’Sullivan, K. P. Phillips, L. Lemyre, E. O’Connor, D. Dow, and W. Corneil. 2007. Ready, aye ready? Suppor t mechanisms for healthcare workers in emergency planni ng: A critical gap analysis of three hospital emergency plans. American Journal of Disaster Medicine 2(4):195-

210.

ASTM International. 2010a. ASTM WK27438: New specification for antimicrobial medical gloves . http://www.astm.org/WorkItems/WK27438. htm (accessed November 11, 2010).

———. 2010b. Product certification . http://www.astm.org/SNEWS/MJ_2010/f 2350_mj10.html (accessed December 8, 2010).

———. 2010c. Standardization news: Antimicrobial medical gloves . http:// www.astm.org/SNEWS/MJ_2010/d1140_ mj10.html (accessed November 29, 2010). Baykasoglu, A., T. Dereli, and N. Yilankir kan. 2009. Application of cost/benefit analysis for surgical gown a nd drape selection: A case study. American Journal of Infection Control 37(3):215-226. California Code of Regulations. 2010. Title 8, Section 5199: Aerosol transmissible diseases standard . http://www.dir.ca.gov /title8/5199.html (accessed November 11, 2010). CDC (Centers for Disease Control and Prevention). 2009a. Interim guidance for emergency medical services (EMS) systems and 9-1-1 public safety answering points (PSAPs) for management of patients with confirmed or suspected swine-origin influenza A (H1N1) infection . http://cdc.gov/h1n1flu/ guidance_ems.htm (accessed December 8, 2010).

———. 2009b. Interim guidance on infection control measures for 2009 H1N1 influenza in healthcare settings, including protection of healthcare personnel

. http://cdc.gov/h1n1flu/guidelines_infection_control.htm (accessed December 8, 2010).

———. 2010. Prevention strategies for seasonal influenza in healthcare settings

. http://www.cdc.gov/flu/professionals/infectioncontrol/healthcaresettings .htm (accessed December 8, 2010). Corley, A., N. E. Hammond, and J. F. Fraser. 2010. The experiences of health care workers employed in an Australian intensive care unit during the H1N1POLICY RESEARCH AND IMPLEMENTATION 153

influenza pandemic of 2009: A phenomenological study. International Journal of Nursing Studies 47(5):577-585. Daugherty, E. L., A. L. Carlson, and T. M. Perl. 2010. Healthcare epidemiology: Planning for the inevitable: Prep aring for epidemic and pandemic respiratory illness in the shadow of H1N1 influenza. Clinical Infectious

Diseases 50(8):1145-1154. Eizenberg, P. 2009. The general practice ex perience of the swine flu epidemic in

Victoria—lessons from the front line. Medical Journal of Australia 191(3):151-153. Hashikura, M., and J. Kizu. 2009. Stockpile of personal protective equipment in hospital settings: Preparedness for influenza pandemics. American Journal of Infection Control 37(9):703-707. IOM (Institute of Medicine). 2008. Preparing for an influenza pandemic: Personal protective equipmen t for healthcare workers . Washington, DC:

The National Academies Press.

———. 2010. Certifying personal protective t echnologies: Improving worker safety. Washington, DC: The National Academies Press. Jensen, P. A., L. A. Lambert, M. F. Iademarco, and R. Ridzon. 2005. Guidelines for preventing the transmission of mycobacterium tuberculosis in health-care settings, 2005. MMWR Recommendations and Reports 54(RR-17):1-141. Koenig, K. L., C. J. Boatright, J. A. Hanc ock, F. J. Denny, D. S. Teeter, C. A. Kahn, and C. H. Schultz. 2007. Health care facilities’ “war on terrorism”: A deliberate process for recommending personal protective equipment. American Journal of Emergency Medicine 25(2):185-195. Lautenbach, E., S. Saint, D. K. Hende rson, and A. D. Harris. 2010. Initial response of health care institutions to emergence of H1N1 influenza: Experiences, obstacles, and perceived future needs. Clinical Infectious

Diseases 50(4):523-527. Murray, M., J. Grant, E. Bryce, P. Ch ilton, and L. Forrester. 2010. Facial protective equipment, personnel, and pandemics: Impact of the pandemic (H1N1) 2009 virus on personnel and use of facial protective equipment. Infection Control and Hospital Epidemiology 31(10):1011-1016. NIOSH (National Institute for Occupa tional Safety and Health). 2010a. NIOSH docket 137: Total inward leakage requ irements for half-ma sk air-purifying particulate respirators . http://www.cdc.gov/niosh/docket/archive/docket137.html (accessed November 11, 2010).

———. 2010b. NIOSH investigation of 3M model 8000 filtering facepiece respirators as requested by the California Occupational Safety and Health Administration, Division of Occupational Safety and Health. HETA 2010-

0044-3109. http://cdc.gov/n iosh/hhe/reports/pdfs/2010-0044-3109.p df (accessed December 8, 2010). OSHA (Occupational Safety and Health Administration). 2007. Employer payment for personal protective equipment; final rule. Federal Register 72(220):64341-64430.154 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

———. 2009. Updating OSHA standards based on national consensus standards; personal protective equipment. Federal Register 74(173):46350-64430.

———. 2010. Infectious diseases. Federal Register 75(87):24835-24844. Perez-Padilla, R., D. de la Rosa-Zamboni, S. P. de Leon, M. Hernandez, F. Quinones-Falconi, E. Bautista, A. Ramirez-Venegas, J. Rojas-Serrano,C. E. Ormsby, A. Corrales, A. Higuera, E. Mondragon, J. A. CordovaVillalobos, and the INER Working Group on Influenza. 2009. Pneumonia and respiratory failure from swine-orig in influenza A (H1N1) in Mexico. New England Journal of Medicine 361(7):680-689. PHAC (Public Health Agency of Canada). 2009a. Guidance: Infection prevention and control measures for health care workers in acute care facilities . http://www.phac-aspc.gc.ca/alert- alerte/h1n1/hp-ps/ig_acf-ld_esaeng.php (accessed D ecember 8, 2010).

———. 2009b. Guidance: Infection prevention and control measures for health care workers in long-term care facilities. http://www.phac-aspc.gc.ca/alertalerte/h1n1/hp-ps/prevention-eng. php (accessed December 8, 2010).

———. 2009c. Guidance: Infection prevention and control measures for prehospital care . http://www.phac-aspc.gc.ca/ale rt-alerte/h1n1/hp-ps/pc-speng.php (accessed D ecember 8, 2010).

———. 2009d. Point of care risk assessment tool for pandemic (H1N1) 2009 flu

virus . http://www.hsabc.org/webuploads/files/h1n1/CNV_1_765_Point_of_ Care_Risk_Assessment_Tool_for_Pandemic.pdf (accessed December 8, 2010). Phin, N. F., A. J. Rylands, J. Allan, C. Edwards, J. E. Enstone, and J. S. NguyenVan-Tam. 2009. Personal protective equipment in an influenza pandemic: A

UK simulation exercise. Journal of Hospital Infection 71(1):15-21. Radonovich, L. J., P. D. Magalian, M. K. Hollingsworth, and G. Baracco. 2009. Stockpiling supplies for the next influenza pandemic. Emerging Infectious

Diseases 5(6):June. Rebmann, T., and W. Wagner. 2009. Infection preventionists’ experience during the first months of the 2009 novel H1N1 influenza A pandemic. American Journal of Infection Control 37(10):e5-e16. Santos, C. D., R. B. Bristow, and J. V. Vorenkamp. 2010. Which health care workers were most affected during the spring 2009 H1N1 pandemic? Disaster Medicine and Public Health Preparedness 4(1):47-54. Siegel, J., E. Rhinehart, M. Jackson, L. Chiarello, and the Healthcare Infection Control Practices Advisory Committee. 2007. 2007 guideline for isolation precautions: Preventing transmission of infectious agents in healthcare settings

. http://www.cdc.gov/hicpac/pdf/isolation/ Isolation2007.pdf (accessed November 16, 2010). Smith, E. C., F. M. Burkle, Jr., P. F. Holman, J. M. Dunlop, and F. L. Archer. 2009. Lessons from the front lines: The prehospital experience of the 2009 novel H1N1 outbreak in Victoria, Australia. Disaster Medicine and Public Health Preparedness 3(Suppl. 2):S154-S159.POLICY RESEARCH AND IMPLEMENTATION 155

Sprung, C., J. Zimmerman, M. Christian, G. Joynt, J. Hick, B. Taylor, G. Richards, C. Sandrock, R. Cohen, and B. Adin i. 2010. Recommendations for intensive care unit and hospital preparations for an influenza epidemic or mass disaster: Summary report of the European Society of Intensive Care Medicine’s task force for intensive care unit triage during an influenza epidemic or mass

disaster. Intensive Care Medicine 36(3):428-443. Swaminathan, A., R. Martin, S. Gamon, C. Aboltins, E. Athan, G. Braitberg, M. G. Catton, L. Cooley, D. E. Dwyer, D. Edmonds, D. P. Eisen, K. Hosking, A. J. Hughes, P. D. Johnson, A. V. Maclean, M. O’Reilly, S. E. Peters, R. L. Stuart, R. Moran, and M. L. Grayson. 2007. Personal protective equipment and antiviral drug use during hospitalization for suspected avian or pandemic

influenza. Emerging Infectious Diseases 13(10):1541-1547. WHO (World Health Organization). 2009. Infection prevention and control in health care for confirmed or suspected cases of pandemic (H1N1) 2009 and influenza-like illnesses . http://www.who.int/csr /resources/publications/ SwineInfluenza_infectioncontrol. pdf (accessed December 8, 2010).

## A

Workshop Agenda

The National Academy of Sciences

Board Room
2100 C Street, NW

Washington, DC

Meeting Agenda

Thursday, February 25, 2010

11:00 a.m. Welcome and Introductions Elaine Larson, Committee Chair

Sponsor’s Charge to the Committee and Background

Information Maryann D’Alessandro, Associ ate Director for Science, National Personal Protective Technology Laboratory (NPPTL), National Institute for Occupational Safety and Health (NIOSH) Les Boord, Director, NPPTL, NIOSH David Weissman, NIOSH Healthcare Program Manager Roland Berry Ann, Deputy Director, NPPTL

Discussion

12:45 p.m. Lunch

1:30 p.m. Context for the Study

157158 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

1:30–2:30 Current NPPTL Research on Personal Protective Equipment (PPE) and Influenza Ron Shaffer, NPPTL

Discussion

2:30–3:30 Project B.R.E.A.T.H.E. and the Respiratory

Protection Clinical Effectiveness Trial Lewis Radonovich, Director, National Center for Occupational Health and Infection Control,

Veterans Health Administration

Discussion

3:30 p.m. Adjourn

Institute of Medicine

Current Research Issues—Personal Protective Equipment for

Healthcare Workers to Prevent Transmission of Pandemic Influenza and Other Viral Respiratory Infections

WORKSHOP

Venable Conference Center

575 Seventh Street, NW Capitol Room–Eighth Floor Washington, DC

Thursday, June 3, 2010

Objectives:

• Provide an overview of recent research (2007–2010)

• Identify lessons learned from the 2009–2010 H1N1 pandemic relevant

to PPE for hea lthcare workers

• Identify research gaps and directions needed for future research

8:00 a.m. Welcome and Opening Remarks Elaine Larson, Chair, Committee on Personal Protective Equipment for Healthcare Workers to Prevent

Transmission of Pandemic Influenza and Other Viral Respiratory Infections: Cu rrent Research IssuesAPPENDIX A 159

8:15 a.m. Panel 1: Research on Influenza Transmission Facilitators: Peter Palese, Allison Aiello

8:15–8:30 Update on animal studies Daniel Perez, University of Maryland 8:30–8:45 Update on environmental monitoring studies Bill Lindsley, NIOSH 8:45–9:00 Update on aerosol-dispersion modeling studies Mark Nicas, University of California–Berkeley 9:00–9:15 Update on nosocomial transmission studies Caroline Breese Hall, Un iversity of Rochester 9:15–9:30 Update on human challenge studies Jonathan Van-Tam, University of Nottingham

9:30–10:00 Discussion with the committee

10:00 a.m. Panel 2: Research on Advances in PPE Technology Facilitators: Karen Coyne, Howard Cohen, Ken Gall, Bill Kojola

10:00–10:25 Update on mask and respirator technology Lisa Brosseau, University of Minnesota 10:25–10:40 Update on PPE performance in preventing

influenza transmission Joe Wander, U.S. Air Force 10:40–10:55 Update on hum an interface research and materials technology Sundaresan Jayaraman, Georgia Institute of Technology 10:55–11:10 Update on face shield/eye protection technology Gilad Shoham, Medonyx, Inc. 11:10–11:25 Update on gown and glove technology Vicki Barbur, Cardinal Health

11:25–12:00 Discussion with the committee

12:00 p.m. Lunch

12:45 p.m. Panel 3: PPE Implementation



### — Observational and

Clinical Studies Facilitators: Richard Wenzel, Allison McGeer, and Bob Cohen

12:45–1:00 Observational studies on PPE use by healthcare

workers and barriers to use Annalee Yassi, University of British Columbia160 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

1:00–1:15 Implementation of PPE programs in California during the 2009–2010 flu season Robert Harrison, University of California–San

Francisco 1:15–1:30 Update on clinical studies Trish Perl, Johns Hopkins University 1:30–1:45 Proposed clinical study Lewis Radonovich, U.S. Department of Veterans

Affairs

1:45–2:15 Discussion with the committee

2:15 p.m. Panel 4: PPE Implementation—Individual and Organizational Studies Facilitators: Bonnie Rogers and David DeJoy

2:15–2:30 Update on research on organizations and worker safety culture David Hofmann, University of North Carolina

2:30–2:45 Update on research on organizational and team learning Ingrid Nembhard, Yale University

2:45–3:00 Dental community experience John Molinari, University of Detroit

3:00–3:15 Update on research on home and community

healthcare workers’ use of PPE Ruth Ann Ellison, Apria Healthcare

3:15–3:45 Discussion with the committee

3:45 p.m. Panel 5: PPE Implementation



### — International and U.S. Policy Research Perspective on the H1N1 Experience with

PPE Facilitators: Gloria Addo-Ayensu and David Prezant

3:45–4:00 Australia’s experience with H1N1 and PPE Dominic Dwyer, Westmead Hospital (via phone) 4:00–4:15 Mexico’s experience with H1N1 and PPE

Rogelio Perez-Padilla, Instituto Nacional de Enfermedades Respiratorias (via phone) 4:15–4:30 New York City’s experience with H1N1 and

PPE Marcelle Layton, New York City Department of Health and Mental Hygiene 4:30–4:45 Update on policy research David Henderson, National Institutes of Health

4:45–5:15 Discussion with the committeeAPPENDIX A 161

5:15 p.m. Public Comment



### — Registered Speakers (3 minutes per speaker) Moderator, Elaine Larson

• Gamunu Wijetunge, National Highway Traffic Safety

Administration

• Donald Milton, University of Maryland

• Nicole McCullough, 3M

• Kathy Robinson, National Association of State EMS

Officials

• Eileen Storey, NIOSH

• Robert Guidos, Infectious Diseases Society of America

• William Borwegen, Service Employees International

Union

• Judene Bartley, Epidemiology Consulting Services, APIC Representative

• Padma Natarajan, Infectious Diseases Society of America

• Leslie McGorman, Infectious Diseases Society of

America

• Korlu Kuyon, Maryland Department of Health and Mental Hygiene, Perkins Hospital Center

6:00 p.m. Summary

Howard Cohen and Richard Wenzel

6:15 p.m. Adjourn

## B

Participants List

Gloria Addo-Ayensu

Director Fairfax County Department of

Health

Allison E. Aiello

John G. Searle Assistant Professor

of Public Health University of Michigan School of

Public Health

Darryl Alexander Program Director American Federation of Teachers,

AFL–CIO

Jennylynn Balmer Employee Safety Programs

Administrator Inova Health System

Evelyn Balogun

Medical Director Temple University Hospital

Vicki Barbur Vice President, R&D Clinician Apparel and Patient

Protection

Cardinal Health Judene Bartley Vice President, Epidemiology

Consulting Services, Inc. APIC Representative

Jo Anne Bennett New York City Department of

Health and Mental Hygiene

Joseph Beres Industrial Hygienist U.S. Department of State

Kim Biedermann

GlaxoSmithKline

Werner Bischoff Assistant Professor, Internal

Medicine Assistant Hospital Epidemiologist Wake Forest University Health

Sciences

William Borwegen Occupational Health and Safety

Director Service Employees International

Union

163164 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Katie Brewer Senior Policy Analyst

American Nurses Association

Lisa M. Brosseau

Associate Professor University of Minnesota School of

Public Health

Gavin Burdge Industrial Hygienist BMT Designers and Planners, Inc.

Karen Caine Department of Health and Human

Services

Leigh Chapman

Infection Prevention Coordinator St. Joseph Medical Center

Elizabeth F. Claverie-Williams Senior Microbiology Reviewer Senior Regulatory Reviewer Food and Drug Administration

Howard J. Cohen

Professor Emeritus University of New Haven

Robert Cohen Director, Pulmonary and Critical

Care Medicine, Cook County Health and Hospitals System Stroger Hospital of Cook County

Matt Conlon Vice President, Market

Development Cantel Medical Corp Katherine Cox Director, Health and Safety

Program American Federation of State,

County, and Municipal Employees International

Karen Coyne Research General Engineer U.S. Army Edgewood Chemical

Biologic Center

Mae Cundiff

Infection Control Preventionist Providence Hospital

Terrell Cunningham

Scientific Reviewer Food and Drug Administration

Maryann D’Alessandro

Associate Director for Science

National Personal Protective

Technology Laboratory National Institute for Occupational

Safety and Health

John Decker

Senior Scientist National Institute for Occupational

Safety and Health

Enjoli DeGrasse Industrial Hygienist

International Brotherhood of

Teamsters

David M. DeJoy

Professor Department of Health Promotion

and Behavior College of Public Health University of GeorgiaAPPENDIX B 165

Steve Duff Sales Manager

LM Gerson

Dominic E. Dwyer Medical Virologist

Centre for Infectious Diseases and

Microbiology Institute of Clinical Pathology and

Medical Research Westmead Hospital, Australia

Ruth Ann Ellison

Vice President Clinical Regulatory Compliance Apria Healthcare, Inc.

Judy Estep Program Associate

Institute of Medicine

June Fisher Physician/Director Training for Development of

Innovative Control Technologies Project

Ken Gall

Professor

School of Materials Science and

Engineering Petit Institute of Bioengineering

and Bioscience Georgia Institute of Technology

Jackie Galluzzo

Infection Prevention and Control

Practitioner St. Joseph Medical Center Bruce Gellin Director, National Vaccine

Program Office Department of Health and Human

Services

George Gentile Medical and First Responder

Program Manager Department of Homeland Security

TroyJennene Gibbs Health and Safety Officer City of Alexandria, VA, Fire

Department

Marta Gill Montgomery County Department of Health and Human

Services Public Health Emergency

Preparedness and Response Program

Joelle Glass

Infection Preventionist Sinai Hospital

Daniel Glucksman

Public Affairs Director International Safety Equipment

Association

Robert Guidos Vice President, Public Policy and

Government Relations Infectious Diseases Society of

America

Caroline Breese Hall

Professor of Pediatrics and

Medicine University of Rochester School of

Medicine166 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Elise Handelman Occupational Safety and Health

Administration

Sarah Hanson Associate Program Officer Board on Health Sciences Policy

Institute of Medicine

Lorraine M. Harkavy Interdisciplinary Scientist

Biomedical Advanced Research

and Development Authority Office of the Assistant Secretary

for Preparedness and Response

Robert Harrison California Department of Public

Health

Frank Hearl

Chief of Staff National Institute for Occupational

Safety and Health

David K. Henderson Deputy Director for Clinical Care Clinical Center, National Institutes

of Health

Kent Hofacre Manager

Battelle

David A. Hofmann Hugh L. McColl Scholar in

Leadership University of North Carolina–

Chapel Hill

Mylena Holguin Senior Market Manager, Infection

Control Apparel

Cardinal Health James Hornstein Vice President, Operations Moldex Metric, Inc.

Christie Huff Vice President, Marketing Safe Life Corp.

Robert Irwin

Senior Advisor

CDC Influenza Coordination Unit

James James Director, Center for Public Health

Preparedness and Disaster Response

American Medical Association

John Jernigan

Centers for Disease Control and

Prevention

Lieutenant Commander Tim Jirus

Office of the Chief of Naval

Operations Safety Liaison

Melanie King

Centers for Disease Control and

Prevention

William Kojola Industrial Hygienist Department of Occupational Safety

and Health

AFL–CIO

David Kuhar

Centers for Disease Control and

Prevention

Korlu Kuyon

Infection Preventionist Department of Health and Mental

Hygiene–Perkins HospitalAPPENDIX B 167

Kevin Landkrohn Occupational Safety and Health

Administration U.S. Department of Labor

Elaine L. Larson

Professor of Ph armaceutical and

Therapeutic Research Columbia University School of

Nursing

Marcelle Layton

Assistant Commissioner

Bureau of Communicable Disease New York City Department of

Health and Mental Hygiene

David LeGrande Director, Occupational Safety and

Health

Communications Workers of

America

Donna Lemmert

Infection Prevention Coordinator Baltimore Washington Medical

Center

Andrew Levinson Occupational Safety and Health

Administration

Yolla Levitt Marketing Manager

3M OHESD

William G. Lindsley National Institute for Occupational

Safety and Health

Cathy Liverman Program Director

Institute of Medicine Sarah Locke

Westat

Elizabeth Lockerby

Infection Preventionist Walter Reed Army Medical Center

Atkinson Longmire Occupational Safety and Health

Administration

Darci MacNab Global Strategic Marketing

Manager Kimberly-Clark

Zina Manji Director, Regulatory Affairs

GlaxoSmithKline Consumer

Healthcare

Tara Martin

GlaxoSmithKline

Brigette Master

3M

Nicole McCullough Manager Technical Services and Regulatory

Affairs

3M

Allison McGeer Director, Infection Control Professor, Laboratory Medicine

and Pathobiology University of Toronto Mount Sinai Hospital

Leslie McGorman Program Officer of Public Health Infectious Diseases Society of

America168 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Ron McGraw

International Association of Fire

Fighters Health and Safety Department

Kathleen McPhaul

Assistant Professor and Chair Occupational Health Section,

American Public Health Association (APHA) University of Maryland and APHA

Maret Millard Technical Service Specialist

3M Infection Prevention Division

Amanda Miller Design Engineer Avon Protection Systems

Donald Milton

Professor and Director Maryland Institute for Applied

Environmental Health University of Maryland

Mary Mohyla Director, Infection

Control/Employee

Health/Accreditation Services Holy Cross Hospital

John A. Molinari

Director of Infection Control

The Dental Advisor

Sheila Murphey

Medical Officer Food and Drug Administration

Elaine Namba

Research Scientist Kimberly-Clark Ingrid Nembhard

Assistant Professor Division of Health Policy and

Administration

Yale School of Public Health

Tom Nerad Occupational Safety and Health

Administration

William Newcomb

National Personal Protective

Technology Laboratory National Institute for Occupational

Safety and Health

Mark Nicas Adjunct Professor University of Ca lifornia–Berkeley

Debra Novak

Senior Service Fellow

National Personal Protective

Technology Laboratory National Institute for Occupational

Safety and Health

Anthony Oliver Office of Emergency Medical

Services

Carolyn Onye Industrial Hygienist

U.S. Coast Guard

Amy Packman

Board Assistant

Institute of Medicine

Peter Palese

Professor and Chair Department of Microbiology

Mount Sinai School of MedicineAPPENDIX B 169

Regina Pana-Cryan

Senior Scientist National Institute for Occupational

Safety and Health

Kapil Panguluri Food and Drug Administration

Stephanie Pasko Senior Product Manager Medline Industries, Inc.

Daniel R. Perez

Associate Professor VA–MD Regional College of

Veterinary Medicine

Rogelio Pérez-Padilla

Director General

Instituto Nacional de Enfermedades

Respiratorias

Trish M. Perl Director, Hospital Epidemiology

and Infection Control Johns Hopkins University School

of Medicine

Jay Peterson Industrial Hygienist

National Institutes of Health

Andrew M. Pope

Board Director

Institute of Medicine

David Prezant Deputy Chief Medical Officer New York City Fire Department

Lewis J. Radonovich National Center for Occupational

Health and Infection Control

Veterans Health Administration University of Florida Virginia Rauer Metropolitan Washington

Association of Occupational Health Nurses, Inc.

Ann Reilly Director, Employee Health St. Joseph Medical Center

Raymond Roberge

National Personal Protective

Technology Laboratory National Institute for Occupational

Safety and Health

Kathy Robinson

National Association of State EMS

Officials

Marc Roe 3M Company

M. E. Bonnie Rogers Director, Occupational Safety and

Health University of North Carolina

School of Public Health

Patricia Rosenbaum

Infection Preventionist Consultant

APIC

Cindy Rosenberger

Infection Preventionist Kernan Orthopaedics and

Rehabilitation

Jack Ross Hartford Hospital

Brenda Roup Nurse Consultant, Infection

Prevention and Control Maryland Department of Health

and Mental Hygiene170 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Kimberly Rumping Program Specialist

Veterans Health Administration–

National Center for Occupational

Health and Infection Control

Bruce Russell

Preventive Medicine

Administrative Officer U.S. Army Medical Department

Activity

Vicken Sarkissian Sperian

Lisa Scheidelman

Infection Control Practitioner St. Joseph Medical Center

Anita Schill

Associate Director for Science National Institute for Occupational

Safety and Health

Roslyne Schulman Director, Policy Development American Hospital Association

Renee Setteducato

Federation of Nurses/United

Federation of Teachers

Ron Shaffer

Branch Chief

National Personal Protective

Technology Laboratory National Institute for Occupational

Health and Safety

Kristina Sherry Reporter/Editor Inside Washington Publishers Gilad Shoham Medonyx, Inc., Canada

Rosemary Sokas

Director Office of Occupational Medicine Occupational Safety and Health

Administration

Gwen Stewart

Infection Preventionist

Infection Control and

Prevention/Employee Health Sibley Memorial Hospital

Eileen Storey Acting Chief, Surveillance Branch Division of Respiratory Diseases National Institute for Occupational

Safety and Health

Jonathan Swerdlin

President MM Herman and Associates, LLC

Linda Sylvester Prince George’s Hospital Center

Michael Tapper Hospital Epidemiologist Lenox Hill Hospital

Barbara Thieman Laurel Regional Hospital

Greg Tilley Principal Engineer Avon Protection Systems

Lisa Tomlinson Senior Director, Government

Affairs

APICAPPENDIX B 171

Jonathan Van-Tam

Professor of Health Protection University of Nottingham

Joseph D. Wander

U.S. Air Force Research

Laboratory

Richard P. Wenzel

Professor Department of Internal Medicine Virginia Commonwealth

University School of Medicine

Katherine West Infection Control/Emerging

Concepts, Inc.

Gamunu Wijetunge

Office of EMS National Highway Traffic Safety

Administration Department of Transportation

James Wilcox Business Development Manager Avon Protection Systems Debbie Wilson

Team Leader Employee Occupational Health Inova Health System

Richard D. Wood Manager, Global Industrial

Hygiene Services Air Products and Chemicals, Inc.

Annalee Yassi Global Health Research Program University of British Columbia

Theodore Yee

Medical Officer Occupational Safety and Health

Administration

Melanie T. Young Policy and Strategic Initiatives

Director Society for Healthcare

Epidemiology of America

## C

Studies of the Clinical Effectiveness of Personal Protective Equipment During Outbreaks of Severe Acute Respiratory Syndrome and Respirat ory Syncytial Virus

TABLE C-1 Studies of the Clinical Effectiveness of Personal Protective Equipment During Outbreaks of Severe Acute Respiratory Syndrome and Respiratory Syncytial Virus

Reference Description Results

Severe Acute Respiratory Syndrome (SARS)

Seto et al.,

2003 Case-control study in five Hong Kong hospitals of 13

SARS-infected staff

and 241 non-infected

staff Odds ratio of staff with specific protection not getting infected:

• Masks: OR= 13 (95% CI 3 to 60, p = 0.0001)

• Gloves: OR = 2 (95% CI 0.6 to 7, p = 0.364)

• Gowns: OR not calculated

• Handwashing: OR = 5 (95% CI 1 to 19,

p = 0.047)

Lau et al., 2004 Case-control study in Hong Kong of 72 hospital workers

with SARS and 144

matched controls • Risk of SARS infection in those reporting problems with mask fit: OR = 1.00 (95% CI 0.51 to 1.95, p = 1.0000)

• Risk of SARS infection in those who had

problems with fogging of goggles: OR = 0.61 (95% CI 0.31 to 1.17)

Continued

173174 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Reference Description Results
Loeb et al.,

2004 Retrospective cohort study of 43 nurses working with SARS patients in Toronto

critical care units Risk of acquiring SARS based on use of

PPE:

• Gown: RR = 0.36 (95% CI 0.10 to 1.24,

p = 0.12)

• Gloves: RR = 0.45 (95% CI 0.14 to 1.46,

p = 0.22)

• N95 (respirator at least once) or surgical

mask: RR = 0.23 (95% CI 0.07 to 0.78,

p = .02)

• N95: RR = 0.22 (95% CI 0.05 to 0.93,

p = 0.06)

• Surgical mask: a RR = 0.45 (95% CI 0.07 to 2.71, p = 0.56)

• N95 vs. surgical mask: b RR = 0.50 (95% CI 0.06 to 4.23, p = 0.51)

Teleman et al., 2004 Case-control study in Singapore of 36

healthcare workers with probable SARS

and 50 healthcare

workers in the same ward with history of

exposure Adjusted odds ratio (m ultivariate analysis)

associated with transmission of SARS:

• Wearing of N95 mask: 0.1 (95% CI 0.02 to 0.9, p = 0.04)

• Wearing of gloves: 1.5 (95% CI 0.3 to 7.2, p = 0.6)

• Wearing of gowns: 0.5 (95% CI 0.4 to 6.9, p = 0.6)

• Handwashing after each patient: 0.07 (95 % CI 0.008 to 0.7, p = 0.02)

Respiratory Syncytial Virus (RSV)

Hall and Douglas,

1981 Comparison of use and nonuse of gowns and masks by staffmembers on a pediatric ward with children < 3 years old • Proportion of infants acquiring RSV:

o When masks and gowns were used by

staff: 32%

o When masks and gowns were not

used by staff: 41%

• Proportion of staff acquiring RSV:

o During the time masks and gowns

were used by staff: 33%

o During the time masks and gowns were

not used by staff: 42%

• Measurable benefit not found in controlling spread of RSV

Murphy et al.,

1981 Prospective study of

use and nonuse of masks and gowns by staff members caring

for infants with respiratory disease • Number of RSV or other respiratory infections did not differ significantlybetween the two groups of staff (handwashing only; and handwashing, gowning, and masking)APPENDIX C 175

Reference Description Results
Gala et al.,

1986 Comparison of use and nonuse of eye– nose goggles by staff

members on an infant

ward • Frequency of RSV infection in hospital personnel:

o Three weeks during goggle use: 8%

( p = 0.003)

o Three weeks with no goggle use: 34%

( p = 0.003)

Agah et al.,

1987 Comparison of use

and nonuse of mask orgoggles by staff members caring for children with RSVinfections on a pediatric inpatient service • RSV illness rate in healthcare workers caring for children with RSV infections:

o Wore masks or goggles: 5% ( p < 0.01compared to no masks or goggles category)

o Did not wear masks or goggles: 61%

Madge et al.,

1992 Prospective study of

four infection controlstrategies in preventing RSV in four pediatric wards • Combination of cohort nursing with useof gowns and gloves significantly reduced RSV infection

• Use of gowns and gloves alone did not

result in a significant reduction of

infection

Langley et al.,

1997 Prospective cohort study comparing isolation policies and

RSV infections in pediatric patients in nine hospitals • Various combinations of requirements for use of gowns, gloves, and masks did

not result in decreased nosocomial rates in patients; gowning for any entry to thepatient’s room was associated with increased risk of RSV transmission NOTE: CI = confidence interval; OR = odds ratio; RR = relative risk. The terms ( masks

, surgical masks , and respirators ) used in this table are those used by the investigators or authors of the cited journa l article or report. In some cases, it is not possible to determine whether the authors’ use of the term masks refers to medical masks, respirators, or both.

a Comparator is use of no mask.

b Consistent use of N95 versus co nsistent use of surgical mask. SOURCE: IOM (2008).



### REFERENCES

Agah, R., J. D. Cherry, A. J. Garakian , and M. Chapin. 1987. Respiratory syncytial virus (RSV) infection rate in pers onnel caring for children with RSV infections. Routine isolation procedure vs routine procedure supplemented by use of masks and goggles. American Journal of Diseases of Children 141(6):695-697.176 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Gala, C. L., C. B. Hall, K. C. Schnabe l, P. H. Pincus, P. Blossom, S. W.

Hildreth, R. F. Betts, and R. G. Douglas, Jr. 1986. The use of eye-nose goggles to control nosocomial respiratory syncytial virus infection. Journal of the

American Medical Association 256(19):2706-2708. Hall, C. B., and R. G. Douglas, Jr. 1981. Nosocomial respiratory syncytial viral

infections. Should gowns and masks be used? American Journal of Diseases of Children 135(6):512-515. IOM (Institute of Medicine). 2008. Preparing for an influenza pandemic: Personal protective equipment for healthcare workers . Washington, DC: The National Academies Press. Langley, J. M., J. C. LeBlanc, E. E. Wa ng, B. J. Law, N. E. MacDonald, I. Mitchell, D. Stephens, J. McDonald, F. D. Boucher, and S. Dobson. 1997.Nosocomial respiratory syncytial virus infection in Canadian pediatric hospitals: A Pediatric Investigators Collaborative Network on Infections in Canada Study. Pediatrics 100(6):943-946. Lau, J. T., K. S. Fung, T. W. Wong, J. H. Kim, E. Wong, S. Chung, D. Ho, L. Y.

Chan, S. F. Lui, and A. Cheng. 2004. SARS transmission among hospital workers in Hong Kong. Emerging Infectious Diseases 10(2):280-286. Loeb, M., A. McGeer, B. Henry, M. Ofner, D. Rose, T. Hlywka, J. Levie, J.

McQueen, S. Smith, L. Moss, A. Smith, K. Green, and S. D. Walter. 2004. SARS among critical care nurses, Toronto. Emerging Infectious Diseases 10(2):251-255.Madge, P., J. Y. Paton, J. H. McColl, and P. L. Mackie. 1992. Prospective controlled study of four infection-control procedures to prevent nosocomial infection with respiratory syncytial virus. Lancet 340(8827):1079-1083. Murphy, D., J. K. Todd, R. K. Chao, I. Orr, and K. McIntosh. 1981. The use of

gowns and masks to control respiratory illness in pediatric hospital personnel. Journal of Pediatrics 99(5):746-750. Seto, W. H., D. Tsang, R. W. Yung, T. Y. Ching, T. K. Ng, M. Ho, L. M. Ho,

and J. S. Peiris. 2003. Effectiveness of precautions against droplets and contact in prevention of nosocomial transmission of severe acute respiratory syndrome (SARS). Lancet 361(9368):1519-1520. Teleman, M. D., I. C. Boudville, B. H. He ng, D. Zhu, and Y. S. Leo. 2004. Factors associated with transmission of severe acute respiratory syndrome among health-care workers in Singapore. Epidemiology and Infection 132(5):797-

803.

## D

Examples of Relevant Voluntary

Consensus Standards

ASTM International standards are u sed extensively by the Food and Drug Administration (FDA) for 510k submissions of personal protective equipment (PPE). Examples of standa rds relevant to PPE used by healthcare workers include the following:

D3577 Specification for Rubber Surgical Gloves

D3578 Specification for Rubber Examination Gloves

D5151 Test Method for Detection of Holes in Medical Gloves

D5250 Specification for Poly(Vinyl Chloride) Gloves for Medical Application

D6124 Test Method for Residual Powder on Medical Gloves

D6319 Specification for Nitrile Examination Gloves for Medical Application

D6499 Test Method for the Immunologi cal Measurement of Antigenic

Protein in Natural Rubber and Its Products

D6977 Specification for Polychloroprene Examination Gloves for Medical Application

F1671 Test Method for Resistance of Materials Used in ProtectiveClothing to Penetration by Blood-Borne Pathogens Using PhiX174 Bacteriophage Penetration as a Test System

F1862 Standard Test Method for Resistance of Medical Face Masks to Penetration by Synthetic Blood (Horizontal Projection of Fixed Volume at a Known Velocity) F2101 Standard Test Method for Evaluating the Bacterial Filtration Efficiency of Surgical Masks Using a Biological Aerosol of

S taphylococcus aureus F2407 Standard Specification for Surgical Gowns Intended for Use in

Healthcare Facilities

177178 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

American National Standards Institute (ANSI)

ANSI has standards that include guidance to employers for the practice of respiratory protection, but not the devices themselves. These include the following:

Z88.2 Practices for Respiratory Protection Z88.6 Medical Qualifications of Respirator Wearers Z88.10 Fit-Test Requirements for Respiratory Protection

The Occupational Safety and Health Administration has incorporated the following ANSI standard into its eye and face protection standard (Code of Federal Regulations 1919.133):

Z87.1 Standard Practice for Occupational and Educational Eye and

Face Protection

Association for Advancement of Medical Instrumentation (AAMI)

AAMI has a standard for fluid resistance of gowns worn by healthcare workers. Minimum performance levels ranging from 1 (least protective) to 4 (most protective) have been determined. These levels apply to the product’s Critical Zone, including seams, but excluding cuffs, hems, and bindings.

National Fire Protection Association (NFPA) Standards

The FDA includes the following NFPA standard into its requirements for masks and respirators:

702 Standard for Classification of Flammability of Wearing Apparel

Another example of a relevant NFPA standard includes

NFPA1999 Standard on Protective Clothing for Emergency Medical Operations

## E

Committee Biographies

Elaine L. Larson, R.N., Ph.D., FAAN, CIC ( Chair ), is associate dean for research and professor of pharmaceutical and therapeutic research, Columbia University School of Nurs ing, and professor of epidemiology, Columbia University Mailman School of Public Health. She is a former dean of Georgetown University School of Nursing. Dr. Larson has been a member of the Board of Directors, National Foundation for Infectious Diseases, and the Report Review Committee, National Academy of

Sciences. She is the director of the Center for Interdisciplinary Research to Prevent Antimicrobial Resistance at Columbia University and has

been editor of the American Journal of Infection Control since 1994. She has published more than 200 journal articles, 4 books, and a number of book chapters in the areas of infec tion prevention, epidemiology, and

clinical research.

Gloria Addo-Ayensu, M.D., M.P.H., is the director of health for Fairfax County, VA. In this capacity she provides overall direction for public health programs in the county, including emergency preparedness. She has led Fairfax County’s comprehens ive pandemic influenza preparedness efforts and engaged a wide range of community stakeholders in theprocess. As past chair of the Metropolitan Washington Council of Governments Health Officials Committee, she facilitated initial coordination of the National Capital Region’s pa ndemic planning in 2006. Dr. AddoAyensu is interested in international health and has served as a consultant to research and public health programs in Ghana.

Allison E. Aiello, Ph.D., is the John G. Searle As sistant Professor of Public Health at the University of Mich igan School of Public Health in the

179180 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Department of Epidemiology. Dr. Aiello held a Robert Wood Johnson Foundation Health and Society Scholars Fellowship at the University of Michigan and an Emerging Infectious Diseases Fellowship at the Centers for Disease Control and Prevention (CDC). Dr. Aiello’s research focuses on the use of non-pharmaceutical interventions, including masks and hand hygiene interventions, for mitigating influenza transmission. She also investigates socioeconomic and race/ethnic disparities in infectious diseases, the relationship between infection and chronic diseases, and the emergence of antimicrobial resistance in the community setting. Herwork on these topics has been presented at numerous national and international conferences and published in peer-reviewed journals, including Lancet Infectious Diseases

, Emerging Infectious Diseases

, American Journal of Public Health

, Journal of Infectious Diseases

, Clinical Infectious Diseases , and the American Journal of Epidemiology . Dr. Aiello is

on the editorial board of the American Journal of Infection Control

, associate editor of BMC Public Health , and an invited member of the American College of Epidemiology Minority Affairs Committee. She received her Ph.D. in epidemiology from Columbia University’s Mailman School of Public Health, where she held a National Institute of Allergy and Infectious Diseases training fellowship and was the recipient of the Ana C. Gelman Award for outstanding achievement and promise in the field of epidemiology.

Howard J. Cohen, Ph.D., M.P.H., CIH, is professor emeritus (formerly professor and chair of the Occupationa l Safety and Health Department) at the University of New Haven. He is an associate (adjunct) professor at Yale University’s Department of Occupational and E nvironmental Medicine. He formerly was the manager ofindustrial hygiene at the Olin Corporation and editor in chief of the American Industrial Hygiene Association Journal . He is certified in the comp rehensive practice of industrial hygiene by the American Board of I ndustrial Hygiene. Dr. Cohen is the

former chair of the American Nati onal Standards Institute Z88.2 committee on respiratory protection and a current member of the editorial board

of the Journal of Occupational and Environmental Hygiene . He is the past chair of the American Industrial Hygiene Association’s (AIHA’s) respiratory protection committee, a past president of the Connecticut River Valley Chapter of the AIHA, and a past officer and treasurer of the American Board of Industrial Hygiene. Dr. Cohen served on the Institute of Medicine (IOM) Committee on Personal Protective Equipment for Healthcare Workers During an Influenza Pandemic and on the IOMAPPENDIX E 181

Standing Committee on Personal Protective Equipment for Workplace Safety and Health. He is currently working as a consultant to the Veterans Administration’s North Florida/ South Georgia Center for Occupational Safety and Infectious Disease (on the Advisory Board and assisting on an upcoming clinical study of influenza). Dr. Cohen is also a consultant to a pharmaceutical company that has developed the first antiviralN95 surgical respirator to be certified by the Food and Drug Administration (FDA) and National Institute fo r Occupational Safety and Health (NIOSH). He is a graduate of Boston University, where he received a B.A. in biology. Dr. Cohen received his M.P.H. and Ph.D. in industrial health from the University of Michigan.

Robert Cohen, M.D., FCCP, is chair of the Division of Pulmonary andCritical Care Medicine for the Cook County Health and Hospitals System and chair of pulmonary and criti cal care medicine at the John H. Stroger, Jr., Hospital of Cook County , IL. His early research focused on the resurgent epidemic of tuberculos is in the City of Chicago and atCook County Hospital. Dr. Cohen has worked closely with patients suffering from chronic obstructive pulmonary disease (COPD), and he founded Cook County Hospital’s pulm onary rehabilitation program. He

has worked as the medical director of the Black Lung Clinics at Cook County Hospital and as medical director of the federally funded Black Lung Clinics Program, a program dedicated to the care of coal miners throughout the United States. He has worked closely with the American Lung Association of Metropolitan Ch icago and is a member of the American Lung Association’s COPD task force, currently serving as themedical director of the Community Spirometry Initiative. He is a recipient of its Public Health Service Award in 2006 and Outstanding Clinician Award in 2007. Dr. Cohen’s work on respiratory disease in coal mining populations has involved cons ulting in areas of mining-related health issues for federal agencies, in cluding the U.S. Agency for International Development (USAID), CDC, and NIOSH. He has recently served as a member of the Mine Safety R esearch Advisory Committee. In addition, he has provided expert consu ltation on occupational lung disease to clinics supported by USAID in Donets k, Ukraine. Dr. Cohen graduated from Northwestern University’s Honors Program in Medical Education in 1981. He did his internship and residency at Cook County Hospital, as well as subspecialty training in pulmonary medicine and critical care.182 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Karen Coyne, Ph.D., is research general engineer at the U.S. Army Edgewood Chemical Biological Center (ECBC). Dr. Coyne has 8 years of experience in respiratory protection research and testing at the U.S. Army ECBC. Her specific areas of expertise are in testing and modelingthe physiological impact of wearing respiratory protection and in developing novel test systems. Prior to this , she spent 7 years at the University of Maryland–College Park (UMCP) , conducting respiratory protection research and developing data collection and instrumentation systems for assessing the impact of protective equipment on respiration, vision, communications, and work performan ce. Dr. Coyne has authored or coauthored 20 journal publications, 8 technical reports, and 18 platform(2 international) and 6 poster conference presentations, has given 5 university guest lectures, and is coinventor on a patent. She taught a physiological modeling course at UMCP for 3 years. She served as a member of the Project B.R.E.A.T.H.E. working group. Dr. Coyne won the John White Best Paper Award in respiratory protection from the Journal of Occupational and Environmental Hygiene for 2000 and 2006 and the Michigan Industrial Hygiene Society Best Paper award in 1998. She received her Ph.D. in biological resources engineering from UMCP.

David M. DeJoy, Ph.D., is professor of health promotion and behavior and director of the Workplace Health Group in the College of PublicHealth at the University of Georgia. Dr. DeJoy has 30 years of experience in workplace safety and health as a researcher, instructor, and consultant. His areas of research include safety climate/culture, work organization, safe work practices, risk communication, and theory-based intervention design/intervention effectiven ess. He has published approximately 120 scientific articles and book chap ters and presented more than 200 papers at scientific and professional meetings. He currently serves on the

editorial boards of Safety Science

, Journal of Safety Research , and Journal of Occupational Health Psychology . Extramural funding for his research has come from CDC, the Nationa l Institutes of Health (NIH), andNIOSH. Dr. DeJoy has served on numerous expert panels, review committees, and advisory panels at th e national and international levels.

Ken Gall, Ph.D., is a professor in the School of Materials Science and Engineering and Mechanical Engineering at the Georgia Institute of Technology. Before joining Georgia Tech in 2005, he was an associate professor of mechanical engineering at the University of Colorado at Boulder and a post-doc at Sandia Na tional Laboratories. Dr. Gall’s re-APPENDIX E 183

search combines polymer chemistry, materials science, bioengineering, and mechanical engineering in order to synthesize and characterize new materials for use in emerging technolog ies. His specific interests include metallic and polymer biomaterials, mechanically active materials, and nanometer scale materials and characterization. He has published more than 130 journal articles, which have been cited more than 2,200 times, and he has given approximately 200 professional talks. He has provided extensive consulting on materials and engineering for law firms, industry, national labs, and the U.S. military. His research on shape memory alloys and polymers was the basis for founding MedShape Solutions, a company developing shape memory material-based orthopedic devices. He received his B.S., M.S., and Ph.D. in mechanical engineering from the University of Illinois.

William H. Kojola, M.S., is the industrial hygienist for the American Federation of Labor and Congress of Industrial Organizations’ (AFL– CIO’s) Department of Occupational He alth and Safety. His experience in health and safety spans more than 30 years. During that time, Mr. Kojola has been the director of the Occupational Safety and Health Division of the Laborers Health and Safety Fund of North America, an occupational safety and health specialist for the International Brotherhood of Boilermakers, and director of safety and health for the United Cement, Lime, Gypsum and Allied Workers Internationa l Union. Prior to this, he was a health research scientist at the University of Illinois School of Public Health, studying the human health effects of air and water pollutants. With the AFL–CIO, Mr. Kojola is r esponsible for developing strategies for securing new safety and health pr otections through federal and state regulations, coordinating with affilia tes on and leading a unified labor response to proposed Occupational Safety and Health Administration (OSHA) regulations, and representi ng the AFL–CIO before government regulatory agencies, on federal advi sory committees, and in consensus standard-setting efforts. He also wo rks with affiliate unions to addressemerging workplace hazards and issues. Mr. Kojola holds a B.S. in biology and an M.S. in genetics from the University of Minnesota, and studied toxicology and industrial hygiene at the University of Illinois School

of Public Health.

Allison McGeer, M.D., is a professor in the Departments of Laboratory Medicine and Pathobiology and at the Dalla Lana School of Public Health at the University of Toronto. In addition to her positions as mi-184 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

crobiologist and director of infection control at Mount Sinai Hospital, Toronto, Dr. McGeer is an infection control consultant to the Baycrest

Centre for Geriatric Care. She cu rrently serves on Canada’s National Advisory Committee on Immunization and on the infection control subcommittee of the Ontario Provincial Infectious Diseases Advisory Committee. She is a member of several local, provincial, and national pandemic influenza committees. She is an expert reviewer for many research funding agencies, including the Canadian Institute of Health Research and U.S. NIH, and has served on the editorial boards of several journals, including the Canadian Medical Association Journal and Infection Control and Hospital Epidemiology . She returned to Mount Sinai Hospital in1989 as a microbiologist and director of infection control. Her major research interests are in the prevention of infection in hospitals and nursing homes, and the use of surveillance to advance the prevention, diagnosis, and treatment of infectious diseases. She is the principal investigator of the Toronto Invasive Bacterial Diseases Network and the Ontario Group A Streptococcal Study, two collabora tive surveillance networks studying the epidemiology of severe community -acquired infections. Dr. McGeer

served on the Council of Canadian Ac ademies expert panel on influenza transmission and the role of persona l protective equipment, and on the IOM Committee on the Development of Reusable Facemasks for Use During an Influenza Pandemic. Dr. Mc Geer completed an undergraduate and master’s degree in biochemistry and her M.D. at the University of Toronto. She specialized in internal medicine and infectious diseases, followed by a fellowship in hospital epidemiology at Yale New Haven Hospital.

Peter Palese, Ph.D., is a professor of microbiology and chair of the Department of Microbiology at the Mount Sinai School of Medicine in New York. His scientific publications incl ude research on the replication of ribonucleic acid (RNA)–containing viruses, with a special emphasis on influenza viruses, which are negativ e-strand RNA viruses. Specifically, he established the first genetic maps for influenza A, B, and C viruses; identified the function of several viral genes; and defined the mechanism of neuraminidase inhibitors (which are now FDA-approved antivirals). Dr. Palese also pioneered the field of reverse genetics for negative-strand RNA viruses, which allows the introduction of site-specific mutations into the genomes of these viruses. This technique is crucial for the study of the structure/function relationships of viral genes, for investigation of viral pathogenicity, and for developm ent and manufacture of influenzaAPPENDIX E 185

virus vaccines. In addition, an impr ovement of the technique has been used effectively to reconstruct and study the pathogenicity of the highly virulent but extinct 1918 pandemic influe nza virus. His recent work in collaboration with Dr. Adolfo Garcia-Sas tre has revealed that most negativestrand RNA viruses possess proteins with interferon antagonist activity, enabling them to counteract the antivir al response of the infected host.

Dr. Palese was elected to the Nationa l Academy of Scie nces in 2000 for

his seminal studies on influenza viruses. He ser ves on the editorial

board for the Proceedings of the National Academy of Sciences and as

an editor for the Journal of Virology . Dr. Palese was president of the Harvey Society in 2004 and is a past president of the American Society for Virology.

David Prezant, M.D., is the chief medical officer and special advisor to the fire commissioner for health policy, fire department of the City of New York (FDNY). He is also a prof essor of medicine in the Pulmonary Division at Albert Einstein College of Medicine. Dr. Prezant is board certified in internal medicine, pulmonary medicine, and critical care

medicine. He is a member of the John P. Redmond International Association of Fire Fighters Medical Advisory Board and represents FDNY as

a member of the technical committee for the Fire Service Joint Labor Management Wellness/Fitness Initiative. Dr. Prezant is the author of numerous peer-reviewed articles on the h ealth and safety of firefighters,thermal protective equipment to reduce burn injuries and improve exercise performance for firefighters, and recently the effect of World Trade Center exposures on respiratory hea lth of firefighters and emergency medical services personnel. Dr. Prezant serves on the IOM Standing Committee on Personal Protective Equipment for Workplace Safety and

Health. He was a member of the IOM Committee on Personal Protective Equipment for Healthcare Workers During an Influenza Pandemic and

the IOM Committee to Review the NIOSH Personal Protective Technology Program. He received his B.S. fro m Columbia College and his M.D. from the Albert Einstein College of Medicine.

M. E. Bonnie Rogers, Dr.P.H., M.P.H., COHN-S, LNNC, FAAN, is an associate professor of nursing and public health and director of the North Carolina Occupational Safety and Health Education and Research Center and the Occupational Health Nursing Program at the University of North Carolina, School of Public Health, Chapel Hill. Dr. Rogers was a visiting scholar at the Hasting Center in New York and is an ethics186 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

consultant. She is certified in occupa tional health nursing and as a legal nurse consultant. Dr. Rogers is a fellow in the American Academy of Nursing and the American Association of Occupational Health Nurses. Dr. Rogers serves as chair of th e NIOSH National Occupational Research Agenda Liaison Committee. She has served on numerous IOM committees, including the Committee on Personal Protective Equipment for Healthcare Workers During an Influenza Pandemic and on the IOM Standing Committee on Personal Protective Equipment for Workplace Safety and Health. Dr. Rogers chaired the recent fast-track IOM study, Respiratory Protection for Healthcare Workers in the Workplace Against

Novel H1N1 Influenza A. She has serv ed in leadership positions for occupational health professional societies and is past president of theAmerican Association of Occupational Health Nurses and the Association of Occupational and Environmental Clinics. Dr. Rogers is currently vice president of the Internationa l Commission on Occupational Health.She received her diploma in nursing from the Washington Hospital Center School of Nursing, Washington, DC; her baccalaureate in nursing from George Mason University, School of Nursing, Fairfax, VA; and herM.P.H. and Dr.P.H. from the Johns Hopkins University School of Hygiene and Public Health.

Richard P. Wenzel, M.D., M.Sc., is professor and former chair of the Department of Internal Medicine at the Medical College of Virginia (MCV), Virginia Commonwealth University (1995–2009). From 2 003 to 2008, he was president of MCV Physicia ns, the clinical practice plan for more than 600 physicians, and senior associate dean for clinical affairs. Dr.

Wenzel’s research has focused on th e prevention and control of hospitalacquired infections, especially bloodstr eam infections and sepsis. He is a nationally recognized expert on antibiotic resistance and its impact. He

has served on the editorial board of New England Journal of Medicine and, in 2001, became the journal’s fi rst editor at large, a position he still holds. Dr. Wenzel has authored more than 500 publications and is editor of 6 textbooks, including A Guide for Infection Control in the Hospital

,which has been translated into 8 languages for free distribution to healthcare workers in developing countries. His popular book, Stalking Microbes , was published in summer 2005. A medical thriller, Labyrinth of

Terror , was released in 2010. Dr. Wenzel is a member of the AmericanSociety of Clinical Investigation and the Association of American Physicians and a charter member of the Surgi cal Infections Society. He is also former president of the Society of Healthcare Epidemiology of America.APPENDIX E 187

From 2006 to 2008, Dr. Wenzel was pres ident of the International Society for Infectious Diseases. He has received numerous awards for research and teaching, including the Humboldt Research Award for Senior U.S. Scientists, a Senior Internationa l Fellowship Fogarty Award from the National Institutes of Health, and the Bruce Award from the American College of Physicians–American Society of Internal Medicine.