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NATIONAL ACADEMY OF SCIENCES

NATIONAL ACADEMY OF ENGINEERING

INSTITUTE OF MEDICINE

NATIONAL RESEARCH COUNCIL

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ISBN

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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 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

Committee on Personal Protective Equipment for 

Healthcare Personnel to Prevent Transmission of 

Pandemic Influenza and Other Viral Respiratory 

Infections: Current Research Issues 

Board on Health Sciences Policy 

Elaine L. Larson and Catharyn T. Liverman, Editors 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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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. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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www.national-academies.org 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

COMMITTEE 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 MCGEER, 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 Public Health, University of North 

Carolina–Chapel Hill 

RICHARD P. WENZEL, Professor and Former Chair, Department of 

Internal Medicine, Virginia Commonwealth University 

v 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

vi

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 Associate
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

vii 

Reviewers

This report has been reviewed in draft 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 independent 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 the 

study 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-
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

viii REVIEWERS

clusions or recommendations, nor did 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 with 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. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 

ix 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

x 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
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 

CO2 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 Occupational Safety and Health 

xi 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

xii ACRONYMS AND ABBREVIATIONS 

NPPTL National Personal Protective 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 

TICD50 tissue culture infective dose50

TIL total inward leakage 

UV ultraviolet 

WHO World Health Organization 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 many unknowns about the virulence, 

spread, and nature of the virus raised to the forefront issues regarding 

personal protective equipment (PPE) for healthcare personnel. A major 

issue 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 of 

improvements 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 unanswered 

research questions provided the impetus for the National Personal Protective Technology Laboratory (NPPTL) at the National Institute for Occupational Safety and Health (NIOSH) to ask the IOM to conduct a study 

1 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

2 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 and 

preparedness, epidemiology, nursing, community health, industrial hygiene, and materials engineering. The IOM committee was charged with 

identifying new research directions, certification2

 and standards-setting 

issues, and risk assessment issues specific to PPE for healthcare personnel to prevent transmission of pandemic 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, 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 that included a public 

comment session, through discussions with numerous individuals in the 

infection control and occupational safety and health fields, and through a 

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

on the work of the IOM committee that released the 2008 report, and 

1

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

offices and facilities as well as those working 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. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

SUMMARY 3

 

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

committee’s task was 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 to 

make 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 occupations, 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 of 

PPE. 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 healthcare field is to clearly understand 

the differences between respirators and face masks as well as their appropriate uses. Respirators are specifically designed as respiratory protection. They work either by purifying the air inhaled by the wearer 

through filtering materials or by independently 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, are 

loose-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 effective component of infection control of 

respiratory diseases, but is not within the scope of this report. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

4 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Measures to prevent influenza transmission 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 hierarchy 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 disease 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 healthcare 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 prepared for the next epidemic or 

pandemic. Experience has shown that relevant research on these issues 

wanes between pandemics, and not permitting 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 humans in terms of their susceptibility 

to infection, the influenza viral strains that display a transmissible phenotype, and the kinetics with which transmission occurs. Experiments per-
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 also 

pointed 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. Nonetheless, data on the viability of influenza and other respiratory viruses in air samples and on fomites in these 

settings are limited. Mathematical models have been 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, the amount of virus in respirable 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 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 for 

recent 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 influenza 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 shields, need to be more fully addressed. Much research has been done regarding filtration of respirator 

media, but ways to improve fit, including new technologies specifically 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

6 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

for filtering facepiece respirators, need more research because face seal 

leakage 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 area 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 studied 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 behavior 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 organizational context. 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 those factors in 

understanding occupational safety performance. 

Although there are clear gaps and deficiencies in our knowledge base 

about PPE usage in health care, existing knowledge is sufficient to recommend a four-pronged strategy for immediate implementation. The 

four 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) accountability 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 aspect of healthcare delivery needs to be carefully 

planned at the organizational/institutional 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-
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

SUMMARY 7

ible. PPE should be factored into all decisions involving task design, 

staffing, and work assignments. Input from frontline workers should be 

used to facilitate planning and decision making and to maximize acceptance. Environmental/engineering controls 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 agencies, labor unions, and others to 

address PPE policies and logistics. Articles 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 as 

information 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 depending on the mode of transmission of 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

8 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, its 

mode 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 research 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 addressing clinical needs and testing the 

results in real-world settings, with the expectation that adaptations along 

the way will be made and tested. Feedback loops to prior stages are also 

critically 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 to 

quickly 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) 

T1 T2 T3 T4 

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

translation of research from basic science research (T1) through policy and regulatory research (T4). See Chapter 1 for further discussion. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

SUMMARY 9

federal agencies as well as ongoing, innovative efforts by PPE designers 

and manufacturers. The report makes 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 particles 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 and 

fund a comprehensive research strategy to improve the understanding of viral respiratory disease transmission, including, but not limited to, examining the characteristics of 

influenza 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. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 in 

designing 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 shields, and face masks in preventing the transmission of influenza or other viral respiratory diseases. Areas of focused 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 Organization 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

SUMMARY 11

NIOSH and other relevant agencies, such as the Agency for 

Healthcare 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 healthcare settings. These efforts 

should include 

• conducting human factors and ergonomics research 

relevant to the design and organization of healthcare 

work 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 Use 

NIOSH and other relevant agencies and professional organizations should support intervention effectiveness research to 

assess 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 settings. 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; 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 a 

broader 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 personnel during the 2009 H1N1 

experience. 

Effectiveness to Disease Reduction in Populations: 

 Systems Research (T3) to Policy and Regulatory Research (T4) 

Recommendation: Develop and Certify Powered Air-Purifying 

Respirators (PAPRs) for Healthcare Personnel

NPPTL should develop certification requirements for a lownoise, loose-fitting PAPR for healthcare personnel. 

Recommendation: Move Forward on Better Fitting Respirators

NPPTL 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 their 

guidance in a timely and coordinated manner as the virulence, contagiousness, and affected populations are further 

characterized. 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 performance of face masks and face 

shields as PPE. The development of standards and certification processes should be guided by research regarding their 

efficacy as PPE: 

• OSHA and CDC should clarify that face masks are 

governed by the general PPE standard (29 CFR 

1910.132) 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 for assessing prevention of transmission of viral respiratory diseases. 

Recommendation: Establish PPE Regulations for Healthcare 

Personnel

CDC, including NIOSH, and OSHA should develop and 

promulgate 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 are 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. 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 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. The committee hopes that this review will jumpstart and 

strengthen improvements in PPE for healthcare personnel that could be 

relevant to a range of viral respiratory diseases. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 the 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 comes at a time when controversies 

continue on issues related to PPE for healthcare personnel while new 

horizons in PPE research and attention 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 unanswered 

research questions provided the impetus for the National Personal Protective Technology Laboratory (NPPTL) at the National Institute for Occupational Safety and Health (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. 

15 
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16 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 preparedness 

and response, epidemiology, nursing, community health, industrial hygiene, and materials engineering. The IOM committee was charged with 

identifying new research directions, certification1

 and standards-setting 

issues, and risk assessment issues specific to PPE for healthcare personnel to prevent transmission of pandemic 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, discussions with numerous individuals 

in the infection control and occupational 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 was 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.
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

INTRODUCTION 17

 

Many PPE issues relevant to healthcare 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 Medicine committee addressed the question 

of 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 personal 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 background issues regarding PPE and its 

use in healthcare settings. In lieu of including extensive background materials, the committee provides an overview 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 health 

and 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 term “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 the 

skin or mucous membrane surfaces. Integrating the various types of pro2

Hand hygiene is another important and effective component of infection control of 

respiratory diseases, but it is not within the purview of this report. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 healthcare field is to clearly understand 

the 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 masks 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 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. A type 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 Occupational 

Safety and Health Administration (OSHA), and user seal checks are required with each use (29 CFR 1910.134). 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 as 

air 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, organizational 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 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. Vaccination against 

influenza has been found to be effective 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 within 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 should be 100 percent of employees who do not 

have medical contraindications and that the level of vaccination coverage among healthcare 

personnel can serve as a measure of a patient safety quality program (CDC, 2010b). 
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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 safety 

and 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 to 

PPE. 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 consensus 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, manufacturers 

of respirators, face masks, and some other types of healthcare PPE are required to obtain FDA approval or clearance by demonstrating equivalence with a similar product on the market. A number of other departments and agencies are involved in various aspects of healthcare PPE. In 

addition to NIOSH within the Centers for Disease Control and Prevention (CDC), the National Center for Emerging and Zoonotic Infectious 

Diseases, in conjunction with the external Healthcare Infection Control 

Practices Advisory Committee (HICPAC), 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 involved in testing and developing PPE for 

military and veterans’ care applications. The Department of Homeland 

Security focuses on emergency response PPE and works to coordinate 

and improve standards and equipment-related issues. The Environmental 

Protection Agency addresses PPE issues relevant to emergency response 

readiness. The Consumer Product Safety Commission has oversight responsibilities for products sold in the commercial marketplace, including 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

INTRODUCTION 21

PPE.4 Professional associations, standards 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. workers 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 healthcare 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 facilities 

as 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 for 

infection risk (e.g., cleaning patient rooms, delivering food) are considered part of the healthcare workforce. This definition is expanded from 

the definition used in the 2008 report. 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, and 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 that 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 stipulating premarket or other 

testing prior to their sale to the public. For those products that assert NIOSH certification, 

NIOSH has the authority to act against mislabeled products. 
Copyright © National Academy of Sciences. All rights reserved.

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22 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

 

appropriate PPE. These issues include interactions 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 agents, healthcare personnel face challenges posed by barrier materials, including having difficulties in verbal 

communications and interactions with patients and family members, 

maintaining tactile sensitivity through gloves, and addressing physiological burdens. 

Some types of PPE are used routinely by clinicians as part of standard infection control precautions designed to protect both the healthcare 

professional and the patient from disease acquisition. CDC has developed a tiered approach to infection control precautions that is detailed 

and reviewed by HICPAC. Standard precautions5

 (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 syncytial 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 worker 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 as 

a starting point for decisions on selecting and using PPE. PPE for healthcare personnel should 

• effectively reduce risks of disease or injury to healthcare 

personnel; 

5

See Siegel et al. (2007) for details on PPE used at each level of precautions. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

INTRODUCTION 23

Work Task/Procedure

Environmental and Organizational Context

Healthcare

Agent/Pathogen Personnel

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 committee 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 section is included here to set the context for the report and to broaden the discussion to include other viral 

respiratory 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. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 years and older (Thompson et al., 

2010). Cases of influenza peak during the winter months in each hemisphere. The influenza A virus is categorized by the subtypes of its major 

surface glycoproteins: hemagglutinin 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 or 

pandemics occur more rarely. In the twentieth century, influenza pandemics occurred in 1918, 1957, and 1968. The highest mortality was in 

the 1918 pandemic, which is estimated to have resulted in 675,000 

deaths in the United States and 50 million 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 65 

than 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 influenza 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 state’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 attention 

focused on an outbreak of infections caused by a previously unrecognized coronavirus that resulted in SARS. Healthcare personnel, partic6

Hemagglutinin mediates the binding of influenza virus to the cells. Neuraminidase is 

involved in the release of virus from infected cells. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

INTRODUCTION 25

ularly those not using PPE and other infection control practices, were 

among the vulnerable groups (CDC, 2003). RSV infections are especially a concern in infants and older adults. The symptoms of RSV infections 

are 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 healthcare personnel. Lessons continue to be learned regarding strategies 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 better 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 must 

wonder 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 depending 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, its 

mode 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 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

26 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 research 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 the expectation that adaptations will 

be made and tested along the way. Feedback loops to prior stages are 

also critically important. Such an integrated approach calls for active collaboration and discourse among scientists 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 research 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) 

T1 T2 T3 T4 

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

translation of research from basic science research (T1) through policy and regulatory research (T4). 

SOURCE: Adapted from Henderson and Palmore (2010) with permission from 

University of Chicago Press. 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 of 

the 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/cdcresponse.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/professionals/acip/specificpopulations.htm (accessed November 30, 2010). 

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

settings. http://www.cdc.gov/flu/professionals/infectioncontrol/healthcare 

settings.htm (accessed December 20, 2010). 

———. 2010d. Respiratory syncytial virus activity—United States, July 2008-

December 2009. Morbidity and Mortality 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. 
Copyright © National Academy of Sciences. All rights reserved.

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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 equipment 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 (accessed 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. 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 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. Evaluation of trivalent, live, cold-adapted 

(CAIV-T) and inactivated (TIV) influenza 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. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 pandemic spread of a swine-like H1N1 

strain 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 mechanisms 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 immediate research needs and longterm research opportunities. 

BACKGROUND AND CONTEXT 

FROM THE 2008 REPORT 

The prior Institute of Medicine report 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 

29 
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30 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 studies can be compared. Box 2-1 provides 

the definitions used by the committee throughout the report, including 

in describing earlier studies. The terms and definitions of the transmission 

routes were developed at a recent Centers for Disease Control and Prevention (CDC) workshop (David Weissman, 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 definitions here are used to frame the discussion, and efforts are needed to reach consensus agreement among the 

many relevant areas of research and clinical care. 

Particle Size: 

• Respirable particles—particles with da ≤ 10 μm 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 μm ≤ da ≤ 100 μm, which can 

be inhaled but cannot penetrate to the 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 person 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: da = aerodynamic diameter. Terminology regarding particles with da > 

100 μm is needed. 

SOURCES: Nicas and Jones (2009); Personal communication, D. Weissman, 

November 2010. 
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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 described 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, and 

healthcare communities would be most helpful in discussing future research and policy. 

Much of the discussion regarding influenza transmission has focused 

on the continuum between droplet spray and aerosol transmission, as 

well as on the role of contact transmission and the potential for transmission through inoculation of the conjunctivae. Aerosol transmission, an 

issue 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 of 

the 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, and number of individuals and their 

interactions within space. Biological factors that may influence transmission include virus strain characteristics, 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). Increased 
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32 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 studied in various animal species—

including mice, guinea pigs, monkeys, and ferrets—with variable results. 

These studies show that animals develop influenza infection, and most 

demonstrate the possible role of aerosol transmission. Experiments performed in the 1930s demonstrated that influenza virus–naïve, asymptomatic ferrets that were caged with influenza virus–infected ferrets would 

subsequently develop disease and that, even in the absence of experimental infection, ferrets occasionally displayed an influenza-like illness, after 

which they became immune to subsequent 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 μm) 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 series of experiments with mice in the 

1960s also provided some evidence suggesting aerosol transmission 

(Schulman, 1968; Schulman and Kilbourne, 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 infection 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 challenges of studying transmission modes. 

One of the most well-known incidents of an influenza A outbreak happened among passengers on a grounded airplane (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 travel–associated outbreak also suggested aerosol transmission with a 37 percent attack rate and wide seat-
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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 more 

laminar 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 patient. At the same time, the authors 

identified an imbalance in the indoor airflow 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 originating 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 clarify 

potential 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 buildings 

with 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 in 

preventing severe acute respiratory syndrome (SARS) or respiratory syncytial virus (RSV) infections (see Appendix C). Challenges in studies of 

this type include difficulties in retrospectively 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 potential 

for creating aerosols, and data are primarily available for SARS, not influenza. Fowler and colleagues (2004) observed a greater risk of devel-
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34 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

oping SARS for physicians and nurses performing endotracheal intubation. Similarly, in a retrospective study of 43 nurses who worked in Toronto with SARS patients, Loeb and colleagues (2004) found that 

assisting 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 is 

transmitted 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 transmission in healthcare settings, including: What activities in the healthcare setting are associated with 

minimal or increased transmission? How distinct is transmission 

in 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 regarding 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? 
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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 and supported. This network would 

facilitate an understanding of the transmission 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-based 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 section 

provides 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 conducted by the committee focused on 

influenza. Searches of bibliographic databases for studies on PPE use 

and transmission were broader and incorporated 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, and 

these 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 highly 
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36 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-range 

spread 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 are 

placed 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 occurs efficiently using both experimental designs, indicating that transmission among ferrets and guinea 

pigs 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 ferret and guinea pig models; early work 

in 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 influenza virus transmission in BALB/c 

mice have been unsuccessful (Lowen et al., 2006); nevertheless, a mouse 

model was used by Schulman and Kilbourne 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 serially adapted in this host, currently the mouse model is not used widely for research on influenza virus 

transmission. 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-
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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 contaminated 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 infected 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 suggest 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 produce 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 closely (through the use of defined 

exposure periods) in the ferret or guinea pig models; the serial collection 

of nasal wash samples over the course 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 detection 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-
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38 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

tions in transmissibility among differing strains of influenza viruses do 

not show a strong correlation with differences 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 Influenza 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 transmit more efficiently than avian-, 

swine-, or mouse-adapted strains. Thus, the low pathogenic avian strains 

A/duck/Alberta/35/1976 (H1N1) and 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 transmitted 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 H1N1 

subtype 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 transmit 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. 
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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 include vaccination; the prophylactic and 

therapeutic use of antiviral drugs; non-pharmaceutical interventions, such 

as 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 vaccination1

 (Lowen et al., 

2009). Also in guinea pigs, twice-daily treatment with oseltamivir reduced titers shed from the upper respiratory 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 animals 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) relative 

humidities (Lowen et al., 2007, 2008). Although field studies are required to translate these findings to the human situation, they suggest that 

the modification of relative humidity in healthcare settings may be a 

means of controlling the spread of influenza virus infection. The impact 

of UV treatment of air on influenza viral spread has not been assessed in 

an animal model; if transmission proceeds 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). 
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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 A 

ribonucleic acid (RNA), and 32 percent contained RSV. Nineteen percent and 38 percent of clinical staff samplers contained influenza A and 

RSV RNA, respectively. A correlation was found between samplers that 

contained 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 this 

specific 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 particles 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 Occupational 

Safety and Health two-stage bioaerosol cyclone sampler or an SKC BioSampler. Of the influenza viral RNA detected, 65 percent was contained 

in 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 collect 

larger 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. 
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Fomite Persistence 

 Studies examining fomite contamination have focused largely on 

virus survivability on environmental surfaces. 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 and 

plastic, 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 studies 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 not 

to 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 inoculated by a touch to contaminated 

fomites, direct infection is likely. In the case of commonly touched fomites, influenza virus may be transferred 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 and 

42 percent picked their nose per 1-hour observation, suggesting that selfinoculation of influenza virus among these healthcare personnel would 

be likely if hands became contaminated 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 influenza A viruses had the lowest log10 reductions per hour. The log10 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 log10 reduction 

per 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 survival in artificially produced aero-
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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 gowns, 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 associated with these embedded materials 

are 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 would 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 transmission 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 influenza. Nonetheless, no recent studies 

identified by the committee have examined 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 influenza survival in the closed environment. However, the converse relationship has been observed outside 

of the United States, where outbreaks have occurred in tropical regions 
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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 is 

more 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 shown that influenza transmission is 

feasible by aerosol, droplet spray, and contact routes, the results of these 

studies have not provided a comprehensive understanding of the relative 

contribution of each mode in causing outbreaks. Mathematical models 

can 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 identified 

and 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 simulations 

that provide varying estimates on different modes of transmission, including the case reproductive number (R0), 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 sources of influenza transmission to 

healthcare personnel through community 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 in 
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diameter); and droplet spray (> 100 μm in diameter). This study used two 

very different assumptions regarding infectivity: (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 tract compared with the upper respiratory tract, droplet spray accounted for 58 percent of the infection risk at 

low salivary viral concentrations, compared 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 concentrations 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 in 

the lower versus upper respiratory tract, hand contact was the major driver of infection across all viral salivary 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 touching the face. Measures for preventing infection caused by droplet spray included fluid-resistant masks 

and eye goggles or face shields. Besides social distancing, the model 

found 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-positive 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 goggles, 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) specifically assessed the dynamics of 

aerosol influenza transmission and found the volume of particles released 

from a sneeze were approximately three-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, and 
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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 dose50 (TCID50) 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 TCID50 produced by a sneeze is higher than that emanating from a cough. 

A model of the risk of aerosol transmission was examined in the setting of a commuter train. Assuming the inhalation of aerosol infectious 

agents during a commute, the estimated R0 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 were 

surgical 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, doubling the number of air ventilation cycles per hour was found to reduce the risk of infection to R0 = 1. 

Although not all healthcare settings are 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 exposure 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 household 

residents. 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-
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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 total 

influenza 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 × 105

TCID50 compared to 1.57 × 105

 TCID50), higher TCID50 required for respiratory epithelium (0.671 TCID50 compared to 0.216 TCID50), and much 

higher TCID50 for nose and eyes (500 TCID50 compared to 0.032 TCID50) 

for influenza compared to rhinovirus. Although the death rate on hands 

was much higher for the influenza virus (55.3 per hour) compared to rhinovirus (0.61 per hour), the death rate on porous and non-porous surfaces 

was 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 unable 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 authors 

provided an integrated method of examining transmission between infected individuals, contaminated environments, 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 toward a hospital or recover without 

hospitalization, 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 asymptomatic 
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individuals contributed less to viral shedding as a result of a decrease in 

symptoms, such as coughing, that may spread disease. The authors found 

that the way that the public responds to information about an outbreak 

can 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 their basic model. Therefore, with an 

asymptomatic subpopulation that is shedding virus, influenza can continue 

to persist within the community even with an R0 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: influenza A/H1N1 strains (recovered 

earlier than 2009 H1N1) and influenza A/H3N2. In human volunteers, 

viral shedding showed a quick increase 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 inoculation, 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 initial inoculation dose. 

Consistent with previous findings, Carrat and colleagues (2008b) determined that an average of 66.9 percent 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 viral 
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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 authors concluded that viral shedding 

peaked 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 and generally healthy. Thus, variability 

in age, immune status, and underlying 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 challenge studies have provided key insights on respiratory virus transmission (Carrat et al., 2008a). Current 

preliminary efforts to develop influenza voluntary challenge studies are 

under 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 secondary infection within the household 

found the period to be longer than previously reported: an average of 3.6 

days (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. 
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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 influenza. Thus, surveillance by symptoms 

may not accurately predict influenza viral activity among healthcare personnel. Influenza vaccination in this study population was low (19.7 percent), and varied by the department where hospital personnel were 

assigned. 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 exposure 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 multiple-crib room acquired nosocomial 

infection (Hall, 2007). Overall, children 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 of 

SARS were examined. Major transmission modes that have been demonstrated include close contact via droplet spray or contaminated fomites 

with respiratory excretion. In addition, 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 contact with stool have been hypothesized as important transmission routes. In a household cluster study by 

Wang 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 sputum, frequent coughing, and watery 
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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 to 

the 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 directly modeled as a method of preventing 

the 2009 H1N1 (Tracht et al., 2010). Considering that the likelihood of 

wearing 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 respirators 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 susceptibility 

and infectivity), the total number of cases would be only minimally reduced (to approximately 73 percent); 

• increasing the percentage of the population wearing surgical 

masks to 50 percent (assumed in this scenario to be 5 percent effective in reducing susceptibility and 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 to 
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approximately 55 percent (a reduction 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 effectiveness at reducing the spread of influenza among susceptible and infected individuals, while N95 respirators 

could reduce the impact of the epidemic, though they could not reduce the 

R0 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 inconsistent because of differences in study 

design, setting, intervention type, and 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 and 

2007. 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 three 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 was 

noted 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 enrollment occurred in conjunction with a 

sick child visit to a healthcare facility. Thus, the mask intervention may 
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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 the 

role 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 residence 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 impacted 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 interventions to urban households. The 509 

households were randomized to receive 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 provided with face masks reported using 

the 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 (2009a) assessed several interventions in 259 households and used secondary transmission of laboratoryconfirmed influenza infection in family members as the outcome measure. Households were identified through household members presenting 

to outpatient clinics with influenza-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-
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giene supplies. Data for all the households in the study found that someone in the household developed confirmed 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 compliance, and disentangling the contribution of layered interventions (i.e., face masks and hand hygiene 

together) when the effect estimate size between layered and non-layered 

interventions may be small. Moreover, in a light influenza season difficulties in identifying cases rapidly can impact the statistical power and 

effectiveness of the interventions, respectively. Last, these types of studies are unable to provide insights on the modes of transmission of influenza because face masks may block 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 value 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 alternative 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. A 
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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 crowded conditions, fewer cases of acute 

respiratory 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 did not) found no differences in occurrence of the common cold, but the small 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 patients. 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 the 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 transmission of H1N1 to healthcare personnel. Many healthcare personnel who were confirmed to have H1N1 

had not cared for H1N1 patients and may have acquired the disease in 

community settings. This hospital had 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 were 
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UNDERSTANDING 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 dispersal 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 febrile 

respiratory 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 be 

used 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-
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56 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

tained. Several subsequent letters to the editor noted issues including that 

measures of exposure risk were missing and the value of triage procedures and the adherence to cough etiquette were not measured 

(Srinivasan and Perl, 2009), concerns 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, including the rates of correct use and 

fit of respirators and masks, the level of environmental contamination, 

the duration and intensity of exposure, 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 better identify sources of infection in 

these types of studies. 

Use of Face Masks and Respirators as Source Control 

Face masks and respirators have also been used as source control, 

that is, placing a mask on patients with 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 mask or 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. 
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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 humans in terms of their susceptibility 

to infection, the influenza viral strains 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 relative 

humidity 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 samples and fomites in these settings are limited. Mathematical models have been 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 respirable 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. Much 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 for 

recent 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 transmission that are needed to inform 
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58 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

decisions on the protection of healthcare 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) and 

have a significant impact on improving the nation’s readiness for pandemic influenza; long-term studies are 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 expedited and coordinated manner as 

possible. 

BOX 2-3 

Findings 

• Standardized terms, definitions, and appropriate classifications are 

needed 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 relative contribution of the transmission routes will require research at many levels, including basic science 

laboratory studies, monitoring studies, 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 aerodynamic diameter of particles and concentration of influenza in aerosols generated by various procedures to 

enable a comparison of aerosol sizes and concentrations of influenza 

generated by coughing, sneezing, talking, and exhalation. 

• The potential for confounding and complexity in conducting intervention 

studies of the effectiveness of PPE within 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. 
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UNDERSTANDING THE RISK TO HEALTHCARE PERSONNEL 59

Animal studies Although data in ferrets and guinea pigs indicate 

that vaccination, antiviral treatment, and altered environmental conditions can each reduce or abrogate transmission, confirmatory and more 

in-depth experimentation would be valuable 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 as 

UV 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 prediction and inferences regarding 

the relative contributions of different transmission modes in varying 

environmental/community contexts. Collaborations between experimental or observational research and mathematical modelers are warranted so 

that the parameters used in mathematical models are based on rigorous 

data and provide evidence that would 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 subjects. Environmental levels of contamination need to be studied, including cultures from air sampling and 

swabs of hard surfaces. Serological studies of exposure to influenza virus 

in family members or roommates would be a reasonable marker of home 

exposure during the study period. Useful measures would also include 

the distribution of the size of respiratory particles of patients exposed to 

the 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 are needed to determine what role 

gowns, gloves, face masks, and respirators might play in influenza 

transmission. Further work on donning and doffing processes is also 
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60 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

needed. Studies should examine whether antiviral-coated PPE provides 

any additional protection and how maintenance and reuse are affected. 

RECOMMENDATIONS 

Recommendation: Develop Standardized Terms and Definitions 

CDC 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 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 and 

fund a comprehensive research strategy to improve the understanding of viral respiratory disease transmission, including, but not limited to, examining the characteristics of 

influenza 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. 

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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 requirements. 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 that has been conducted in the past 

several years. The chapter concludes with the committee’s thoughts on 

research gaps and immediate and long-term research directions. 

71 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

72 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 functionality requirements for other types of 

PPE, numerous other factors play a significant role in the design and development of healthcare PPE. These factors include issues involving visibility, comfort and wearability, durability, maintenance and reuse, aesthetics, and cost (Figure 3-1). 

In considering a framework for the 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 evidence-based performance requirements for personal protective equipment (PPE). 

SOURCE: IOM (2008). 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 (Figure 

3-1) 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 tested 

in 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 research 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 μm particles that do not penetrate the test filter (IOM, 

2008). Influenza viruses, with estimated sizes ranging from approximately 0.08 to 0.12 μm (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 inward 

face 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, powered 

air-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 types of PPE that might be needed to 

protect workers from infectious disease. These types of barrier protection 

are 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 fabric, with four levels of liquid 

barrier performance defined by the Association for the Advancement of 

Medical Instrumentation’s (AAMI’s) testing standard, AAMI PB70. The 

prior report emphasized the need to explore whether specific clinical situations require varying types of gowns or whether other specifications 

are needed, as well as issues regarding feasibility of reuse, interface with 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

74 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 shields, 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 relevant to influenza transmission 

(IOM, 2008). 

Healthcare personnel’s use of gloves 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 proper hand hygiene is performed, and 

increasing awareness of the potential for self-inoculation when gloved 

hands 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 hygiene 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. 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 masks 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 for 

those 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 latex sphere tests and 4 to 90 percent 

in the sodium chloride (NaCl) tests. Dental masks showed significantly 

higher penetration (6 to 75 percent for latex and 53 to 90 percent for salt) 

than hospital masks (0.02 to 0.7 percent for latex and 4 to 37 percent for 

salt). Only 1 of the hospital masks (mask H) had less than 5 percent penetration of the salt particles. Lee and colleagues (2008c) investigated the 

protection 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 the 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, Brosseau 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 Oberg 
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76 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 intended 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 particles 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 smaller 

viral- and bacterial-sized particles. Eninger and colleagues (2008b) reviewed the NIOSH aerosol particle-size distribution and measurement 

method. The authors found that, although the salt aerosol does contain a 

significant fraction of ultrafine (diameters < 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 significantly 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 performance 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 when 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 further research is needed with cyclic 

flows with high peak inspiratory flows. 

A study of the filtration performance 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.
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DESIGNING AND ENGINEERING EFFECTIVE PPE 77 

in the 4 to 30 nm range at 85 L/min found that both types of respirators 

showed a decrease in percentage of penetration, with a decrease in particle diameter down to 4 nm (Rengasamy et al., 2008). This study supports prior studies that indicate that NIOSH-approved air-purifying 

respirators provided expected filtration 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 Norm 

requires 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 for 

both 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 flow and four cyclic flow conditions 

were used. Penetration increased under increasing constant- and cyclicflow conditions. The MPPS for the P100 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 facepiece respirator. They identified 

the greatest need for further research as human laboratory or workplace 

protection factor studies to measure TIL for respirators used for protection against nanoparticles. Wander and 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 particles of the same size have the 

same impact on the filtering efficiency of filtering facepiece respirators. 
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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 nanoparticle 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 polydispersed NaCl, well above that of N95 

respirators. Penetrations of 9 to 98 percent were obtained for different 

monodisperse NaCl aerosol nanoparticles. These materials had penetration levels similar to some face masks that were tested previously. They 

concluded that only minimal protection 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. Several 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 the 
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DESIGNING AND ENGINEERING EFFECTIVE PPE 79 

masks provided adequate protection. Oberg and Brosseau (2008) evaluated facial fit of 5 face masks using qualitative and quantitative fit tests 

with 20 human volunteers. When the subjects put on the face masks 

themselves, 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 tested 

attained 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 cannot 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 glued 

to 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, consideration should be given to the 

possible 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 the 

loose-fitting PAPR they tested would act as a buffer against contaminated air that leaks into the respirator 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 recently (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) found 
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80 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 percent 

required testing with 3 or more respirators. Therefore, multiple respirators are likely to be needed to get passing 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 important 

factor. 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 anthropometrics (Roberge, 2009). Wilkinson and colleagues (2010) found that personnel who reported their race as Asian had 

the highest failure rate and that race 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 the fit test, pass rates were similar 

to 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 respirator 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, moderate, and heavy intensity tasks in a 

steel 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 considered 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 suggestions for improving the fit capabili-
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DESIGNING AND ENGINEERING EFFECTIVE PPE 81 

ties of respirators. Au and colleagues (2010) proposed using a customizable, reusable mask with high-efficiency 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 mask that is cut to size. Only 16 of 

the 22 volunteers had a fit factor greater than 100. This was lower than 

the pass rate for the N95 (19/22), but was not significantly different. The 

authors concluded that the customizable 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 leakage 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 demonstrated high 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 particle 

sizes 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 exhalation 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. 
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82 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL 

Preventing a Patient from Spreading Virus 

One suggestion for protecting personnel from virus exposure is to 

place 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 an 

N95 respirator (4.1 percent of control). Placing positively charged polypropylene edging on the mask and respirator 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 of the cough jet and directed it upward, downward, and out of the sides of the mask. The leakage air from 

both the mask and respirator had little momentum. They concluded that 

both face masks and N95 respirators decelerated and redirected the expelled air, which then joined the general upward motion of the cougher’s 

thermal 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 transmission of infectious aerosols 

from a source to a receiver. Although an N95 on the source filtered significantly more particles than the face masks, the simulated workplace 

protection 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 blocked virus expulsion. However, Huang 
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DESIGNING 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 optics 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 research is needed to understand the particle dynamics of exhaled viruses while wearing a face mask or respirator 

in order to make a recommendation regarding 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 alone 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 penetration 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 respirator 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 et 

al., 2008b; McMahon et al., 2008; Winter et al., 2010). Multiple respirators should be available for healthcare 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 penetration levels (Viscusi et al., 2009a). 

Participants in a no-fit respirator workshop (Brosseau, 2009) identified 

the need for a user seal check that works, continuous fit checking rather 

than a no-fit test, and a respirator that can be put on easily multiple times. 
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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 respirators has been suggested as a strategy to counteract anticipated supply shortages during a pandemic and to 

reduce costs. The potential for the respirator to serve as a fomite is a serious concern. Safe, effective decontamination methods that inactivate 

the 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 protective 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 contaminant 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 test 

system (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 of viable particles on PPE, recovery methods are needed that allow removal without killing the virus. 

Casanova and colleagues (2009) developed a new technique for recovering bacteriophage MS2, a non-enveloped virus, from contaminated 

gloves, 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 that > 10 percent of the challenge 
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DESIGNING AND ENGINEERING EFFECTIVE PPE 85 

MS2 bacteriophage survived for 20 hours at 22°C and 30 percent relative 

humidity. 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 influenza 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 effective means for decontamination 

that does not affect the structure and integrity of the respirator. Viscusi 

and coworkers (2007, 2009b) assessed the effect of decontamination methods on filter aerosol penetration, physical appearance, and airflow resistance. From their initial list of 10 potential decontamination methods (autoclave, isopropyl alcohol, bleach, hydrogen peroxide, microwave, soap 

and water, ultraviolet [UV] radiation, dry heat, vaporized hydrogen peroxide, and ethylene oxide) (2007), liquid hydrogen peroxide, vaporized 

hydrogen peroxide, and UV radiation caused the least change in filter 

performance. The authors (2009b) then further evaluated five decontamination methods (UV germicidal irradiation, ethylene oxide, vaporized 

hydrogen peroxide, microwave oven irradiation, and bleach) on three 

models each of N95, P100, and surgical N95 filtering facepiece respirators. Ethylene oxide and UV germicidal irradiation were the only methods that did not cause any observable physical changes to the respirators. 

The bleach method left a noticeable odor, even after overnight drying, 

and bleach off-gassed when the decontaminated respirators were rehydrated with deionized water. UV germicidal irradiation, ethylene oxide, 

and vaporized hydrogen peroxide were the most promising decontamination methods, although there are concerns regarding throughput for the 

latter two methods. 

Fisher and colleagues (2009) investigated a process for applying viral droplets to respirators to evaluate decontamination methods. Two decontamination methods, one physical (steam) and one chemical (bleach), 

were examined as well as two concentrations of organic matter (protec-
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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 Virucidal Agents 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 differences 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 concentrations of organic matter were used. 

This would be important for a decontamination 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-log10 reductions in MS2, while higher doses resulted in no 

detectable MS2. The authors discussed that further research is needed 

because 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 residual 

chemicals on six models of filtering facepiece respirators after seven decontamination methods: ethylene oxide, 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 the ethylene oxide reacted with rubber 

parts 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 byproduct. It also has problems with 

throughput, as does vaporized hydrogen peroxide. Other techniques such 
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DESIGNING 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 effectiveness on inner filter layers and pleats 

is unknown, as is its affect on electrostatic 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 control 

and 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 the 

efficacy 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 dioxide–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 log10 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 log10 reduction, which was not significantly different from the control. The iodinated respirator showed 3.7 log10 reduction of MS2 at 4 hours. This was 

significantly higher than the control, while the others were not significantly different from the control. Therefore, the decontamination efficacy 
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88 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL 

of the antimicrobial respirators depends on storage conditions and the 

antimicrobial agent. Iodine from the filter that enters the extraction medium may also inactivate virus. 

Borkow and colleagues (2010) investigated the antiviral properties of 

a copper oxide–containing N95 respirator. Treated and control respirators were exposed to aerosolized human 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 particles 

did 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 environmental 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 copper oxide–impregnated filter media 

show promise for inactivating virus in the respirator. 

Respirators: Tolerance, Physiological Responses, 

and Communications 

Respirators worn by healthcare personnel have the potential to impact comfort, physiological responses, task performance, and communications with each other and with patients. Protective equipment, such as 

respirators or face shields, may create pressure points that cause discomfort. The breathing resistance and dead volume of the respirators may 

alter respiration and lead to a build-up of carbon dioxide. Because respi-
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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 the 

mouth, muffling speech and removing visual cues for the listener. Additionally, the noise created by a PAPR blower and environmental noise 

both hinder communications. Several researchers 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 benefits 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 appear to be assigned N95 respirators for use, elastomeric respirators 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, and 

the comfort scores were not significantly different from controls (no respirator). Complaints of subjective symptoms and design features of the 

respirator included facial heat, skin irritation, and weight of the respirator, among others. 

Little is known about the tolerability of healthcare personnel to wearing respirators, particularly during an influenza pandemic where they 

likely would be required to be worn for 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 willing to wear a variety of respirator 

ensembles (including N95s, PAPRs, half-face elastomerics, and face 

masks in various combinations) while performing their normal job duties. Healthcare personnel stopped wearing their respirator ensemble before the end of an 8-hour shift in 59 percent of the total work shifts 

evaluated by the study. Reasons given for discontinued wear included 

communication difficulties (visual, auditory, or vocal), heat, pressure or 

pain, and dizziness or difficulty concentrating, among others. Median 

tolerance times varied by the respirator ensemble worn, ranging from 4.1 
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90 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL 

to 7.7 hours. Wearers of disposable models often complained of facial 

heat and pressure, while users of reusable models often reported communication problems. A cup-shaped N95 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 tolerance 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 interesting 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 exhalation 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 general 

population, 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 largest adverse subjective ratings were 

for comfort, face, breathing, heat, and heavy weight of the device. The 

largest differences between the two types of respirators were for subjective measures of nose impact and heavy weight, with the elastomeric 

model demonstrating the greater adverse impact among subjects on these 

two measures. Overall, however, the study concluded that while both 

respirator types were “relatively well tolerated,” N95 respirators may be 

preferable to elastomeric respirators. 

Although not much is known about what workers would like to see 

incorporated into future respirator designs 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 respondents 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 a 
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DESIGNING 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 colleagues (2008) found small but statistically significant increases in both inhalation and exhalation resistances of 

a face mask placed over an N95 filtering 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 concluded 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 impairments 

were 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 juice 

jugs) 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 versus 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). However, 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, including those with mild respiratory impairments. 

Another study used thermal imaging to assess surface temperature of 

two N95 respirators and two N95 respirators with exhalation valves from 

the same manufacturer (Monaghan et al., 2009). Respirators were placed 

on 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 benefits over a mask without one. 
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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 physiological 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 (CO2). 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 levels 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 CO2

values did not statistically differ (elastomeric 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 CO2 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 notice 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 CO2 was not a 

problem. Therefore, the benefit of the exhalation valve may be seen only 

at higher work rates. 

Healthy workers and those with mild respiratory impairments should 

be able to physiologically tolerate respirators. 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-
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DESIGNING AND ENGINEERING EFFECTIVE PPE 93 

den due to their positive air flow. However, the weight of the blower 

may increase the physiological workload. 

Communications 

Healthcare personnel must be able to communicate effectively and 

accurately with each other and with patients while wearing PPE. Communications while wearing PPE typical of healthcare personnel has been 

investigated by Mendel and colleagues (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 normal 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 investigate 

the 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. The 

elastomeric 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 different 

from the control, and the three respirators with speech augmentation performed better than those without augmentation. 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 was 
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94 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 developed 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 rates of 32 to 55 percent with 3 subjects performing face-to-face communications. The quietest PAPR had 

the 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 the 

elastomeric 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 speech 

communications. 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. Speech 

augmentation devices or voice projection units may also improve communications. The Department of Homeland 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 techniques 

being 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, the 

impact of decreased communications on patient care and procedural outcome is unknown. 
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DESIGNING AND ENGINEERING EFFECTIVE PPE 95 

Current Research Directions

 NIOSH recently supported a research effort (Brosseau, 2009) that 

examined ways to improve fit for half-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 during 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 coatings, and whether respirator use 

reduces infection rates in emergency departments. Wearer characteristics 

that the group identified as contributing 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 fit; 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 Protective 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 information exchange, prototype development, prototype lab and human subject testing, and commercialization. 

Nine federal departments and agencies are participating in the working 

group. The group met in 2008 to discuss issues of safety and effectiveness, impact on occupational activities, comfort and tolerability, and 
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96 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 organizations with the ability to design and 

manufacture a respirator that meets the needs of Project B.R.E.A.T.H.E. 

(Federal Register, 2009). It is anticipated 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 low 

inhalation and exhalation resistance rates of filtering facepiece respirators do not significantly impact respiration. Although hypoventilation 

occurs with full-facepiece air-purifying respirators, neither the Bansal 

and colleagues (2009) nor the Roberge and colleagues (2010a,b,c) studies showed any evidence of such a burden with N95 filtering facepiece 

respirators or elastomeric respirators. Respirators do impact communications. However, the impact of decreased speech intelligibility on task 

performance is unknown. Loose-fitting 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 for 

healthcare 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 generally decreases, which then has the 

potential to impact comfort and tolerability (i.e., cause an increase in heat 

levels experienced by the wearer). A recent study has demonstrated that 

medical 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 clothing offers the potential to help reduce heat stress and improve thermal comfort for healthcare personnel. 
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DESIGNING AND ENGINEERING EFFECTIVE PPE 97 

Phase-change materials provide cooling 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 finishing treatments, the impact of temperature and relative humidity in the work environment, the use of multiple layers, and changes that can result from laundering or cleaning that 

might impact the protective effects of the clothing (Laing, 2008). The 

issue of laundering was further reviewed by Wilson and colleagues 

(2007), who assessed the limited available literature and found that industrial laundering and home laundering 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 personnel (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 having the highest compliance rate (96 

percent) and physicians having the lowest (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). The study authors did not note whether 

an 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 healthcare 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 reminder 
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98 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 examined to reduce contamination 

(Jones et al., 2010; Newman et al., 2007). 

As with gowns and protective clothing, one active area of research is 

the use of antiviral coatings or other 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, and 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 confirmed (Chan et al., 2010). Case reports of 

conjunctivitis have been noted with the H7N7 avian influenza virus 

(Fouchier et al., 2004). Protective eyewear and face shields can reduce 

self-inoculation and may provide protection against droplet spray. Little 

is known about how well these devices protect the wearer from direct 

contact, 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 face 

shields, 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 surgery 
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DESIGNING 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 all other eye-protective devices (50 

percent for standard surgical telescopic loupes, 30 percent for face-mask 

and eye-shield combinations, and 3 percent for disposable glasses). Studies have also examined eye protection 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 of 

blood and body-fluid splashes. Similar studies would be useful to evaluate the exposure of healthcare personnel 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 Performance and New Materials 

Task Performance 

The ability of medical staff to perform tasks and medical procedures 

while wearing PPE is a concern. Several recent studies assessed the impact of various levels of PPE on the 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 of 

chest 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 and colleagues (2007) assessed the ability 

of emergency department doctors and nurses to perform trauma resuscitation in level C PPE (air-purifying respirator, hooded suit, and inner and 
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100 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL 

outer gloves) versus gowns and gloves. Although volunteers believed the 

PPE impaired pulse assessment, IV cannulation, IV-line attachment, 

mini-jet use, bag and mask ventilation, and communication, only the 

time 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 and 

once 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 the 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 were 

performed 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 performance than the more close-fitting 

air-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 assess 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 PPE 

items for protection against bloodborne or other infectious agents, including a respirator, gloves, a gown, eye or face protection, and in some 

cases 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 provided and contamination is avoided. 

Workers in fields such as law enforcement, firefighting, and health care 
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DESIGNING AND ENGINEERING EFFECTIVE PPE 101 

have critical needs to be able to perform specific tasks while wearing 

multiple 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-specific 

PPE 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 shields 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 and 

other 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 their jobs. Important advances have 

been 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 addressed. Much research has been done 

regarding filtration of respirator media, but ways to improve fit, including new technologies specifically for filtering facepiece respirators, need 

more research because face seal leakage 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 operational 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 address the needs of healthcare personnel 

(e.g., patient–provider interaction, comfort, reduced physiological burden) 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

102 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL 

have been identified. Addressing these 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 on 

designing and engineering effective PPE to prevent transmission of influenza and other viral respiratory diseases. At its June 2010 workshop 

and through its literature review, the committee realized that many research efforts have been completed recently and that ongoing research 

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

and to broaden them into areas that will result in wearable and effective 

PPE 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 for 

PPE 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 of 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

DESIGNING 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 filtration. 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 respirators 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 has 

focused 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. Develop 

improved and simpler fit testing methods. Examine the effectiveness of performing a user seal 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 time 
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104 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 studies 

to 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 and 

effectiveness 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 in 

designing 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 shields, and face masks in preventing the transmission of influenza or other viral respiratory diseases. Areas of focused 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. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 Personnel

NPPTL 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. 

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the filtration performance of 21 N95 filtering face piece respirators after 

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Evaluation of five decontamination methods for filtering facepiece 

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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. 
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Vojtko, M. R., M. R. Roberge, R. J. Vojtko, R. J. Roberge, and 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 particle containing viable H1N1. Pittsburgh, PA: 

National Institute for Occupational Safety and Health. 

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Abstract P212: Simulated pediatric resuscitation during novel H1N1 

influenza outbreak. Circulation 120:S1487-S1488. 

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donning a gown during cardiopulmonary resuscitation in a simulation 

model. Canadian Journal of Emergency Medical Care 10(4):333-338. 

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workers: Survey results. Infection Control and Hospital Epidemiology

31(9):918-925. 

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D. Tolley. 2008. Blood splash injury: An underestimated risk in 

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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 manufacturers 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 personnel 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 facilities. The chapter concludes with 

recommendations for future research. 

BACKGROUND AND CONTEXT FROM THE 2008 REPORT 

Although healthcare personnel often face hazardous working conditions with potential exposures to a variety 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 discussed in Chapter 3. Few studies 

have tested interventions to improve adherence rates. 

113 
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114 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 and 

performance feedback, workplace policies, and training and education programs. 

Discussion in the 2008 report focused on the concerted efforts 

needed by individual healthcare personnel, managers, and institutions to 

improve the safety culture in healthcare 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 healthcare 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), microorganizational 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 industry; 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 include 

commitment to safety articulated from the highest level of the organization; resources, incentives, and rewards to carry out the commitment; 

continuous emphasis on safety; safety as the priority even at the expense 

of production or efficiency; communication across all levels that is frequent and candid; openness about errors and issues as well as regular 

reporting; and valuing organizational 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-
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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 and sincere engagement by those in 

leadership positions who model, encourage, and enforce appropriate PPE 

use and safety. Finally, and importantly, 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; factors 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 been 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 not wearing PPE during appropriate situations, and supervisors should reinforce the importance of PPE and enforce policies so that noncompliance is the 

rare exception and not the rule. . . . Each healthcare employer 

should assume responsibility for taking an active role in facilitating, promoting, and requiring safety actions. Healthcare facilities 

need to foster and promote a strong culture of safety that includes a 

commitment to worker safety, adequate access to safety equipment, and extensive training efforts that utilize protocols requiring 

specific safety actions and detailing consequences for noncompliance. (IOM, 2008, p. 8) 
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116 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

4. Clarify worksite practices and policies: Much remains to be 

learned about specific issues related 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 information to other healthcare facilities 

could 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. In 

addition to PPE, the continuum of infection prevention and safety controls includes environmental and engineering controls (e.g., number of 

air exchanges, availability of isolation rooms with negative-pressure ventilation) and administrative or work practice controls (e.g., protocols to 

ensure early disease recognition, vaccination 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 relationship 

between 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 healthcare 

workplace (Lowe, 2008; Singer et al., 2009; Tucker et al., 2008). Highhazard industries, such as commercial aviation and nuclear 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, construction, 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 culture concepts. Investigators further 

indicated that safety culture emerged as an important theme in encouraging PPE use, which included proper training, personal responsibility, 

peer pressure to use PPE, and appropriate and comfortable equipment. 

Supervisor and peer use of PPE was deemed important. As noted by 
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USING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 117

Lombardi and colleagues, “If the supervisor doesn’t have [protective 

eyewear] on, no one else is going to wear them” (2009, p. 758). Positive 

reinforcement was seen as encouraging; 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 number 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 PPE 

as 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 personnel, 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 broader 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 and 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 of 
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118 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 coverage 

about 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 constipators.” Active resisters were identified as hospital staff who actively and openly opposed changes in practice. One person identified this group as “entrenched culture.” Another 

type of active resister was one who had competing authorities on new 

practice implementation, such as hospital policy being in conflict with 

Centers for Disease Control and Prevention guidelines. Organizational 

constipators tended to be mid- to high-level executives who prevented or 

delayed certain actions, thereby acting as barriers to evidence-based 

change implementation. They appeared to undercut changes and put their 

own interests ahead of those of organizations 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 protection. 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 keeping employees informed and up to 
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USING 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 a 

South 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 hospital 

staff 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 importance 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 differences 

may be at least partially related to task assignments and the general organization of work (Chiang et al., 2008). Chiang and colleagues found 

that physicians complied better than nurses with PPE requirements during resuscitation activities in an intensive care unit. In this study, the 

poorer 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, and 

other 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 poor 
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120 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 personnel with respect to proper PPE 

usage, modes of transmission, and other infection control topics. Research by Bryce and colleagues (2008) found that even though healthcare 

personnel 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 devices regardless of fit test results, and 

not getting fit tested annually. Composite compliance and comfort scores 

were assessed for use of N95 respirators 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 of 

full 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 protective 

eyewear, the ability to see clearly was significantly and positively associated with both compliance and comfort. No association was reported 

between 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 identified with respect to properly 

removing PPE (Hitoto et al., 2009), differentiating 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 compliance 

behaviors 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 indicate 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-
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USING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 121

lieve they know more about PPE and infection control than they actually 

do (Shigayeva et al., 2007). Studies on the willingness of healthcare providers to work during crises involving 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 patient–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 hospital emergency department were asked 

to wear a respirator (P2, an N95 equivalent) for a 4-week period during 

the influenza season whenever they were 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 communication, and had to be stored 

somewhere between uses. 

Patient perceptions of PPE and its impact on provider behaviors is an 

area 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 and 

expected as the norm (Molinari, 2010). Using a set of pictures of physicians with transparent face shields and 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). 
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122 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Interventions to Improve Infection Control 

and/or PPE Compliance 

Gammon and colleagues (2007) conducted 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 in 

the 13 studies examining interventions (primarily training classes) to improve compliance. In most intervention 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 services 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. However, 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 was 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 reduced 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 the 

work 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). 
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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 planning is the more than 1.5 million home healthcare personnel and those working in community settings 

other than hospitals and large clinics (e.g., schools, physician’s offices, 

long-term care settings) in the United States (Baron et al., 2009). These 

settings 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 during 

an 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 41 

workers 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 whether 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) conducted 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 been 

done 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 behavior 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 organizational context. Daugherty and colleagues (2009) found that knowledge and task hindrances were related to 

poor compliance among critical care clinicians, with the authors concluding that organizational factors were more important than individual fac-
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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 base 

about PPE usage in health care, existing knowledge is sufficient to recommend a four-pronged strategy for immediate implementation. The 

four elements are as follows: (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) 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 organizational/institutional level, managers and 

frontline workers alike need to understand and accept their roles and responsibilities, and PPE usage needs to be as easy and convenient as possible. PPE should be factored into all 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 controls 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 work has 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. Furthermore, much can be learned from recent experience by healthcare personnel and organizations during the 
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USING PPE: INDIVIDUAL AND ORGANIZATIONAL ISSUES 125

2009 H1N1 influenza, and exploring lessons learned can be instructive 

for moving research efforts forward. Increased knowledge and communication on the severity of the disease will also be important as decisions 

are made by organizations regarding 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 organizational and other barriers that 

limit the use of PPE by healthcare personnel 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 and 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 are 

needed 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 and organizational levels; comprehensive training, including supervisors and managers; widespread 

and convenient availability of appropriate PPE devices; and accountability at all levels of the organization. 
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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 safety 

climate specific to the healthcare arena and PPE use. This includes examining the applicability to health care of research 

findings in the areas of patient safety, high-reliability organizations, high-hazard industries, and general industry. Lessons 

learned from the experience with 2009 H1N1 influenza could be 

informative in identifying best practices, learning from organizations successful with PPE compliance by healthcare personnel as 

well as from those with lower rates of compliance, and examining issues relevant to PPE policy and implementation relevant to 

both large and small healthcare employers. To improve appropriate use of PPE, it will be vital to better understand the motivations and risk assessment processes used by healthcare personnel 

regarding use of and demand for PPE. 

• Incentives and enforcement: Innovative approaches to incident 

reporting systems and other incentive 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. 
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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 for 

Healthcare 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 healthcare settings. These efforts 

should include 

• conducting human factors and ergonomics research 

relevant to the design and organization of healthcare 

work 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 Use 

NIOSH and other relevant agencies and professional organizations should support intervention effectiveness research to 

assess 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 settings. 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; 
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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 a 

broader 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 personnel during the 2009 H1N1 experience. 

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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

5 

Policy Research and Implementation: 

Healthcare Systems, Standards, 

and Certification 

The emergence of 2009 H1N1 influenza and the ensuing dilemmas 

regarding personal protective equipment (PPE) for healthcare personnel 

highlighted challenges in healthcare delivery 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 more 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 implemented by the Occupational 

Safety and Health Administration (OSHA) impact workplace access to 

133 
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134 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 Regulations [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 of 

PPE, 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 consensus 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 Institute for Occupational Safety and 

Health (NIOSH) proposed total inward 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 been 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 protect 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 Disease 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 using 

N95s 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 CDC 

guidelines, healthcare employers in California would, for example, protect personnel against seasonal influenza 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 influenza 
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POLICY 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 conformity 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 rubber 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 International 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 devices used in healthcare environments 

are considered medical devices and are regulated as either Class I or Class II 

devices. 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 require 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 currently 

on 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 medical devices; the agency reviews 

data submitted by manufacturers to demonstrate that the product has been 

tested (by the manufacturer or an independent 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 protection against infectious diseases 

such as influenza. Therefore, masks and respirators have requirements that are 

continued 
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136 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

specifically geared for surgical room use, 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 control the manufacture and sale of PPE. 

These regulations do not specifically apply to employers or employees. Requirements regarding the use of PPE in the healthcare workplace are overseen by the 

Occupational Safety and Health Administration (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. Testing and certification requirements are 

incorporated 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 certification requirements are specific to the 

type of respirator (e.g., air-purifying, self-contained breathing apparatus) and are 

not specific to the type of workplace where 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 treatments 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 proper use of PPE in 

the workplace, including in healthcare facilities. The two main regulations relevant to PPE use by healthcare personnel relevant to viral respiratory diseases 

are 29 CFR 1910.134, which governs the use of respirators, and 29 CFR 

1910.132, which governs the use of PPE other than respirators. All respirators 

used by healthcare personnel must be NIOSH 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 Control and Prevention (CDC) provides in-
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 use of respirators (respirators are recommended for aerosol-generating procedures 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 availability 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 personnel, such as home healthcare agencies. The use of PPE is included in the Joint Commission’s requirements for 

employers. 

State and local health agencies provide 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 (such as the American National Standards Institute and ASTM International) work 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. Most 

standards 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 manufacturer 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 barrier 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 importance of protecting the worker, 

particularly when dealing with hazards of unknown severity or health 
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138 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

impacts. For novel respiratory viruses, 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 report, 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 and 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; a 

role 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 consensus 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 and consider if selection, maintenance, storage, and inspection requirements for face masks and face 
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POLICY RESEARCH AND IMPLEMENTATION 139

shields should be detailed in OSHA regulations 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 of 

a novel viral respiratory disease. During an emergency situation, employers may run out of respirators that have been fit tested on personnel 

and 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 respirator to ensure proper fit and protection 

(29 CFR 1910.134). The challenge during an emergency situation could 

be the need to do fit testing for large 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 needs 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 workers. 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 employers and workers with better fitting respirators. 

PAPRs During an influenza pandemic, some healthcare personnel who 

do 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 facial 
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140 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

features that do not allow them to be fitted adequately to a typical N95 or 

other tight-fitting respirator. These individuals would need to be assigned 

a 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 interactions, including speech perception and 

listening to chest sounds. Efforts are underway by the National Personal 

Protective Technology Laboratory (NPPTL) to develop regulations for 

testing and approving lower flow PAPRs 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 standard includes a list of diseases and 

pathogens that require airborne precautions as outlined by CDC, including “novel or unknown pathogens” (California 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 facilities 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 agents 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 adequate protection 

for healthcare personnel and that would, 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 medical 

device, the Food and Drug Administration (FDA) stipulates that the respirators must be NIOSH certified and meet flammability and fluid pro-
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POLICY RESEARCH AND IMPLEMENTATION 141

tection standards; these standards are not relevant for most situations in 

which workers must be protected from influenza. During the recent pandemic, the FDA identified non-cleared respirators that would be acceptable for healthcare personnel. To alleviate this issue for future crises, the 

FDA 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 by 

a 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 preventing transmission led to a variety of 

recommendations at different times by federal and local government 

public health agencies. Delayed and/or disparate recommendations often 

led to confusion among healthcare personnel 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 recommendations 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, workshop 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 Alliance (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). 
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142 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

In NYC, the fire department emphasized the need for paramedics and 

emergency medical technicians to use 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 virulence 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 respirators. In anticipation of the 

second wave of H1N1 returning in Fall 2009, the city health department, 

working with the NYC Office of Emergency Management, 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 experiencing 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 and 

droplet 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 respirator (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. CDC 

recommended 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 personnel “who are in close contact” with 

patients with confirmed or suspected 2009 H1N1, for personnel “en-
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POLICY RESEARCH AND IMPLEMENTATION 143

gaged in aerosol generating activities,” and for personnel involved in the 

“interfacility transfer” of patients with 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 infection

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 

versus 

aerosolgenerating 

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). 
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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 published 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 and 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 examined the use of facial protective 

equipment from late June through mid-December 2009 in three Vancouver, Canada, hospitals. During that time, 865 patients with suspected cases 

of H1N1 influenza were admitted, with 149 patients having laboratoryconfirmed H1N1 influenza infection; 134,281 masks and 173,145 N95 

respirators 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-
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POLICY RESEARCH AND IMPLEMENTATION 145

 

ties and types of PPE needed to respond 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 Virginia Hospital Allliance Emergency 

Preparedness and Response Program, reported that member hospitals 

developed regional stockpiles of respiratory 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 considered the size of the facility and 

the number of providers to get final estimates for distribution. Supplies 

of 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 departments 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 contact1

 with a suspected 

case. The researchers reported an average of 12 close contacts, with 19 

exposures 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 being within 1 meter of a patient or within an isolation 

room. 
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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 defined 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 (this included an N95 respirator for 

medium-risk and a surgical mask for low-risk workers). The researchers 

also estimated that two surgical masks 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 hospital during an 8-week pandemic—

nearly 20,000 N95 respirators, 122,000 surgical masks, 21,000 goggles 

and gowns, and 172,000 pairs of gloves would be needed. This study 

provides an initial start on the question of estimated quantities, but is 

theoretical and based only on published 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, including 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 research 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 and pediatric emergency departments 
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POLICY RESEARCH AND IMPLEMENTATION 147

had the highest infection rate per department. 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 during the initial phases of H1N1. Early 

in the epidemic, Perez-Padilla and colleagues (2009) reported their experience in Mexico City. They focused on the clinical presentation of 

H1N1, but also noted information on the transmission of disease to 

healthcare 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 out 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 then 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 varied respiratory symptoms and were 

treated with oseltamavir. 

Focus group discussions with a group of infection preventionists in 

the United States pointed out the logistical 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, approximately one-third said that PPE-use 

guidelines changed at their facilities about halfway through the event.

A survey of healthcare epidemiologists, 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 recommendation for airborne precautions for 

suspected H1N1 cases was appropriate at the beginning of the H1N1 crisis” at his or her institution (Lautenbach 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 concern 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). 
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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 reported 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 movement 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 to 

pandemic 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 agencies, labor unions, and others to 

address PPE policies and logistics. Articles 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 
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POLICY 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 as 

information 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 gathered 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. 
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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 and coworkers. Recognition of this 

fact is the foundation for an aggressive vaccination program for healthcare personnel. 

RECOMMENDATIONS 

Recommendation: Move Forward on Better Fitting Respirators

NPPTL 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 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 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 their 

guidance in a timely and coordinated manner as the virulence, contagiousness, and affected populations are further 

characterized. 

Recommendation: Standards and Certification for Face Masks 

and Face Shields

NIOSH, OSHA, and standards-development organizations 

should develop the standards and certification processes 
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POLICY RESEARCH AND IMPLEMENTATION 151

needed to assess the performance of face masks and face 

shields as PPE. The development of standards and certification processes should be guided by research regarding their 

efficacy as PPE. 

• OSHA and CDC should clarify that face masks are 

governed by the general PPE standard (29 CFR 

1910.132) 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 for assessing prevention of 

transmission of viral respiratory diseases. 

Recommendation: Establish PPE Regulations for Healthcare 

Personnel

CDC, including NIOSH, and OSHA should develop and 

promulgate 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 are 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 landscape 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-
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 committee hopes that this review will 

jumpstart and strengthen improvements in PPE for healthcare personnel 

that could be relevant to a range of viral respiratory diseases. 

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POLICY RESEARCH AND IMPLEMENTATION 155

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C. Sandrock, R. Cohen, and B. Adini. 2010. Recommendations for intensive 

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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 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, Associate 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 

157 
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158 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 healthcare 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: Current Research Issues 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

APPENDIX 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, University 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 human 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 Columbia 
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160 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 committee 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

APPENDIX 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
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 

163 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

164 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 Georgia 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

APPENDIX 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 

Medicine 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

166 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 Hospital 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

APPENDIX B 167

Kevin Landkrohn 

Occupational Safety and Health 

Administration 

U.S. Department of Labor 

Elaine L. Larson 

Professor of Pharmaceutical 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 

America 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

168 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 California–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 Medicine 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

APPENDIX 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 Hygiene 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

170 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 

APIC 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

APPENDIX 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 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

C 

Studies of the Clinical Effectiveness of Personal 

Protective Equipment During 

Outbreaks of Severe Acute Respiratory 

Syndrome and Respiratory 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 

173 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

174 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 (multivariate 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 staff 

members 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 significantly 

between the two groups of staff (handwashing only; and handwashing, gowning, and masking) 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 or 

goggles by staff members caring for children with RSV 

infections on a pediatric inpatient service 

• RSV illness rate in healthcare workers 

caring for children with RSV infections: 

o Wore masks or goggles: 5% (p < 0.01 

compared to no masks or goggles category) 

o Did not wear masks or goggles: 61% 

Madge et al., 

1992 

Prospective study of 

four infection control 

strategies in preventing RSV in four 

pediatric wards 

• Combination of cohort nursing with use 

of 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 the 

patient’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 journal 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 consistent 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 personnel 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. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

176 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

Gala, C. L., C. B. Hall, K. C. Schnabel, 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. Wang, 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. Heng, 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. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

D 

Examples of Relevant Voluntary 

Consensus Standards 

ASTM International standards are used extensively by the Food and 

Drug Administration (FDA) for 510k submissions of personal protective 

equipment (PPE). Examples of standards 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 Immunological 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 Protective 

Clothing 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 

Staphylococcus aureus 

F2407 Standard Specification for Surgical Gowns Intended for Use in 

Healthcare Facilities 

177 
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178 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 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 Nursing, 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 infection 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 comprehensive pandemic influenza preparedness efforts and engaged a wide range of community stakeholders in the 

process. As past chair of the Metropolitan Washington Council of Governments Health Officials Committee, she facilitated initial coordination 

of the National Capital Region’s pandemic 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 Assistant Professor of Public Health at the University of Michigan School of Public Health in the 

179 
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180 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. Her 

work 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 Occupational Safety and Health Department) 

at the University of New Haven. He is an associate (adjunct) professor at 

Yale University’s Department of Occupational and Environmental Medicine. He formerly was the manager of industrial hygiene at the Olin Corporation and editor in chief of the American Industrial Hygiene Association Journal. He is certified in the comprehensive practice of industrial 

hygiene by the American Board of Industrial Hygiene. Dr. Cohen is the 

former chair of the American National 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 IOM 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

APPENDIX 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 antiviral 

N95 surgical respirator to be certified by the Food and Drug Administration (FDA) and National Institute for 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 and 

Critical Care Medicine for the Cook County Health and Hospitals System and chair of pulmonary and critical care medicine at the John H. 

Stroger, Jr., Hospital of Cook County, IL. His early research focused on 

the resurgent epidemic of tuberculosis in the City of Chicago and at 

Cook County Hospital. Dr. Cohen has worked closely with patients suffering from chronic obstructive pulmonary disease (COPD), and he 

founded Cook County Hospital’s pulmonary 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 Chicago and is a member of the 

American Lung Association’s COPD task force, currently serving as the 

medical 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 consulting in areas of mining-related 

health issues for federal agencies, including the U.S. Agency for International Development (USAID), CDC, and NIOSH. He has recently served 

as a member of the Mine Safety Research Advisory Committee. In addition, he has provided expert consultation on occupational lung disease to 

clinics supported by USAID in Donetsk, 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. 
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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 modeling 

the 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 performance. 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 Public 

Health 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 effectiveness. He has published approximately 120 scientific articles and book chapters 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 National Institutes of Health (NIH), and 

NIOSH. Dr. DeJoy has served on numerous expert panels, review committees, and advisory panels at the 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 National Laboratories. Dr. Gall’s re-
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

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 technologies. 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 Health 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 International 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 responsible for developing strategies 

for securing new safety and health protections through federal and state 

regulations, coordinating with affiliates on and leading a unified labor 

response to proposed Occupational Safety and Health Administration 

(OSHA) regulations, and representing the AFL–CIO before government 

regulatory agencies, on federal advisory committees, and in consensus 

standard-setting efforts. He also works with affiliate unions to address 

emerging 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-
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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 currently 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 in 

1989 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 collaborative surveillance networks studying 

the epidemiology of severe community-acquired infections. Dr. McGeer 

served on the Council of Canadian Academies expert panel on influenza 

transmission and the role of personal protective equipment, and on the 

IOM Committee on the Development of Reusable Facemasks for Use 

During an Influenza Pandemic. Dr. McGeer 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 include research on the replication of 

ribonucleic acid (RNA)–containing viruses, with a special emphasis on 

influenza viruses, which are negative-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 development and manufacture of influenza 
Copyright © National Academy of Sciences. All rights reserved.

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APPENDIX E 185

virus vaccines. In addition, an improvement of the technique has been 

used effectively to reconstruct and study the pathogenicity of the highly 

virulent but extinct 1918 pandemic influenza virus. His recent work in collaboration with Dr. Adolfo Garcia-Sastre has revealed that most negativestrand RNA viruses possess proteins with interferon antagonist activity, 

enabling them to counteract the antiviral response of the infected host. 

Dr. Palese was elected to the National Academy of Sciences in 2000 for 

his seminal studies on influenza viruses. He serves 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 professor 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 health 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 health 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. from 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 ethics 
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Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010

186 PERSONAL PROTECTIVE EQUIPMENT FOR HEALTHCARE PERSONNEL

consultant. She is certified in occupational 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 the 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 served in leadership positions for occupational health professional societies and is past president of the 

American Association of Occupational Health Nurses and the Association of Occupational and Environmental Clinics. Dr. Rogers is currently 

vice president of the International 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 her 

M.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 2003 to 

2008, he was president of MCV Physicians, the clinical practice plan for 

more than 600 physicians, and senior associate dean for clinical affairs. Dr. 

Wenzel’s research has focused on the prevention and control of hospitalacquired infections, especially bloodstream 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 first 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 American 

Society of Clinical Investigation and the Association of American Physicians and a charter member of the Surgical Infections Society. He is also 

former president of the Society of Healthcare Epidemiology of America. 
Copyright © National Academy of Sciences. All rights reserved.

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APPENDIX E 187

From 2006 to 2008, Dr. Wenzel was president 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 International Fellowship Fogarty Award from the 

National Institutes of Health, and the Bruce Award from the American 

College of Physicians–American Society of Internal Medicine. 
Copyright © National Academy of Sciences. All rights reserved.

Preventing Transmission of Pandemic Influenza and Other Viral Respiratory Diseases: Personal Protective Equipment for Healthcare Workers: Update 2010