**Chapter 9. Epidemiology and Surveillance**

**Overview**

Effective vaccine-preventable disease (VPD) surveillance at national,
state and local levels serves to document the impact of vaccination
programs, to evaluate the effectiveness of current vaccines and
vaccination policies, and to identify needed changes in program
strategies. It also tracks trends in disease over time, monitors
progress toward disease reduction and elimination goals, and serves to
signal the need for public health responses.

Surveillance is used to evaluate the impact of changes in immunization
policies. Surveillance is especially critical following the introduction
of a new vaccine to monitor post-licensure vaccine safety, coverage and
decline in disease. Surveillance must be very complete for those
diseases with extremely low incidence, especially those for which there
is a target of elimination. For many diseases, especially those for
which testing is required for diagnosis and/or case confirmation,
surveillance may rely heavily on laboratory based reporting to increase
the completeness of case reporting.

The Council of State and Territorial Epidemiologists (CSTE) has the
responsibility to decide what diseases should be reported nationally.
Priority areas of concern for CSTE are surveillance and epidemiology of
infectious diseases, chronic diseases and conditions, and environmental
health concerns. CSTE promotes the effective use of epidemiologic data
to guide public health practices and improve health. This is
accomplished by supporting the use of effective public health
surveillance and good epidemiologic practice through training, capacity
development, peer consultation, developing standards for practice, and
advocating for resources and scientifically based policy.

The role of immunization programs in VPD surveillance varies
considerably from state to state, with many immunization programs
sharing this responsibility to a greater or lesser degree with other
organizational sections, branches, or divisions responsible for general
communicable disease control or epidemiology. However, to meet the
national disease elimination objectives established for VPD
surveillance, activities will need to be intensified and enhanced. With
many VPDs at all time low levels, the involvement of immunization
program management and staff will be essential to assure complete case
identification and thorough case investigation.

Monitoring adverse events and addressing vaccine safety concerns is an
essential part of an immunization program. The National Childhood
Vaccine Injury Act (NCVIA) of 1986 mandated the reporting of certain
adverse events following immunization. This act led to the establishment
of the Vaccine Adverse Event Reporting System (VAERS), a passive
reporting system for adverse events following receipt of any U.S.
licensed vaccine. VAERS is operated jointly by the CDC and the Food and
Drug Administration (FDA). VAERS is the cornerstone of a comprehensive
vaccine safety monitoring program to maintain public confidence in
vaccines and vaccination programs.

Public and private immunization programs perform a critical role in
vaccine safety by ensuring that their providers report suspected adverse
events following vaccination through VAERS. Because VAERS is a passive
surveillance system, there may be underreporting or biased reporting.
Furthermore, VAERS usually cannot determine if an adverse event was
actually caused by a vaccine. By collating and analyzing VAERS data
nationwide, FDA and CDC are able to identify and respond to
vaccine-associated risks potentially not identified in pre-licensure
assessments. In addition, VAERS can detect unusual increases in
recognized events, vaccine lots with unusual numbers or types of
reported events, and, by collecting and following up additional case
information, may detect pre-existing conditions that may be
contraindications to vaccination. Results of VAERS analyses are used to
trigger investigations of hypothesized relationships between a vaccine
and adverse events.

VAERS data are available via the VAERS website
([www.vaers.hhs.gov](http://www.vaers.hhs.gov/)). Routine updates and/or
custom searches are available to grantees on request from the VAERS
program. Adverse events designated as serious require additional
follow-up by the VAERS program to obtain more complete medical
information with which to evaluate the case. These and other
enhancements to CDC's vaccine safety efforts will add to the knowledge
regarding vaccine safety and help maintain confidence in our vaccination
programs.

Currently the NCVIA specifies vaccines/toxoids and types of events that
must be reported. However, healthcare providers are encouraged to report
all clinically significant events to VAERS. Reporting forms and
instructions are available from the VAERS website
([www.vaers.hhs.gov](http://www.vaers.hhs.gov/)), or by calling
1-800-822-7967, or by sending an e-mail to <info@vaers.org>.

To modernize and enhance public health surveillance and information
systems, CDC and its public health partners are implementing the
National Electronic Disease Surveillance System (NEDSS). NEDSS
implementation strategies include ensuring that the relevant activities
of state and local immunization programs are consistent with the
functional and technical specifications of the NEDSS information
architecture. State and local immunization programs should evaluate
current activities with respect to the NEDSS information system
architecture and modify these activities, if necessary, so that they are
consistent with NEDSS specifications. Information describing these
specifications can be found on the internet at
<http://www.cdc.gov/nedss/BaseSystem/NEDSSRequirements.pdf>.

**References**

-   CDC. Manual for the Surveillance of Vaccine-Preventable Diseases
    <http://www.cdc.gov/nip/publications/surv-manual/default.htm>

-   Healthy People 2010 National Objectives, (DHHS)
    <http://www.healthypeople.gov/Document/HTML/Volume1/14Immunization.htm>

-   CDC. Managing a Hepatitis B Prevention Program: A Guide to Life as a
    Program Coordinator
    <http://www.cdc.gov/ncidod/diseases/hepatitis/resource/perinatalhepB.htm>

-   Hepatitis Surveillance Report No. 51, Sept. 2006
    <http://www.cdc.gov/ncidod/diseases/hepatitis/resource/PDFs/hep_surveillance_61.pdf>

-   Information about the Vaccine Adverse Events Reporting System
    (VAERS) is available at
    [www.vaers.hhs.gov](http://www.vaers.hhs.gov/), telephone
    800-822-7967; fax 877-721-0366, <info@VAERS.org>.

-   Information about the National Childhood Vaccine Injury Act is
    available at <http://www.cdc.gov/nip/vacsafe/#NCVIA>

-   Information about the Council of State and Territorial
    Epidemiologists is available at
    [http://www.cste.org](http://www.cste.org/)

-   Information about the National Electronic Disease Surveillance
    System is available at <http://www.cdc.gov/nedss>

-   CDC. Morbidity and Mortality Weekly Report website:
    <http://www.cdc.gov/mmwr>

-   CDC. Revised Standards for Child and Adolescent Immunization
    Practices. Available at
    [http://www.cdc.gov/nip/recs/rev-immz-stds.htm]{.underline}

-   CDC. Revised Standards for Adult Immunization Practices. Available
    at <http://www.cdc.gov/nip/recs/rev-immz-stds.htm>

-   2008-2012 Immunization Program Operations Manual (IPOM) Chapters 1,
    5, 6, 7 and 8[\
    ]{.underline}

**Program Requirements**

**9.1 Implement and maintain surveillance systems to investigate and
document cases and outbreaks of vaccine-preventable diseases, in
accordance with CDC's "Manual for Surveillance of Vaccine-Preventable
Diseases."**

[Required activities]{.underline}

9.1a. For Congenital Rubella Syndrome (CRS), diphtheria, *Haemophilus
influenzae*, hepatitis A, hepatitis B, measles, meningococcal disease,
mumps, pertussis, polio, invasive pneumococcal disease, rubella,
tetanus, pediatric (\<18 years of age) influenza deaths, and varicella:

-   Investigate each suspected case and implement public health
    activities, as appropriate.

-   In accordance with guidance in CDC's "Manual for Surveillance of
    Vaccine-Preventable Diseases," ensure that appropriate clinical
    specimens are tested and relevant epidemiologic information is
    collected.

[Recommended activities]{.underline}

> 9.1b. Develop administrative policies and procedures to assure the
> systematic, institutionalized reporting of cases and suspected cases
> of VPDs by providers, healthcare institutions, schools, day care
> centers, universities, and laboratories.
>
> 9.1c. Obtain the authority for health department staff to review
> medical records of persons who are cases or suspected cases of all
> VPDs.
>
> 9.1d. Ensure availability of written up-to-date guidelines for case
> investigation, outbreak investigation, and outbreak control of all
> VPDs. In program areas where an immunization information system (IIS)
> is operational, incorporate the use of IIS into case investigation
> guidelines when documenting the vaccination status of cases and
> controls.
>
> 9.1e. Ensure that health department staff responsible for VPD
> surveillance and response is trained to perform VPD case and suspect
> case investigations, outbreak investigations, and outbreak control.
>
> 9.1f. Initiate VPD case investigations and outbreak investigations
> promptly and complete outbreak control measures and other necessary
> public health interventions in a timely manner.
>
> 9.1g. Develop and distribute written up-to-date laboratory guidelines
> for each VPD detailing the appropriate clinical specimens for testing,
> the recommended laboratory tests and laboratories, appropriate
> specimen handling, and expected timelines for laboratory results.
> Ensure that laboratory capacity is available for testing clinical
> specimens for VPDs.
>
> 9.1h. Ensure that clinics, schools, day care facilities, hospitals and
> other VPD reporting sites routinely submit surveillance reports to
> health departments.
>
> 9.1i. Conduct enhanced, active surveillance in communities where a VPD
> is prevalent, or where there is increased incidence.
>
> 9.1j. Pursue unreported cases of VPDs by searching laboratory,
> hospital and/or death certificate data, especially for VPDs which are
> rare or uncommon.
>
> 9.1k. Investigate outbreaks occurring in schools, child care and
> institutional facilities, and offer control efforts either through
> provision of vaccine in public clinics or by referrals to primary
> healthcare providers. In outbreak settings, obtain clinical specimens
> from at least one case for laboratory confirmation.

**9.2 For routine reporting, collaborate with appropriate staff to
submit timely and complete electronic case/death reports to CDC for
cases of VPDs designated as reportable by the Council of State and
Territorial Epidemiologists (CSTE)
<http://www.cdc.gov/epo/dphsi/nndsshis.htm>, including cases as
described in the case confirmation status print criteria approved by
CSTE <http://www.cdc.gov/epo/dphsi/phs/infdis.htm>, applying guidance as
provided in the "Manual for Surveillance of Vaccine-Preventable
Diseases." <http://www.cdc.gov/nip/publications/surv-manual/default.htm>
Outbreaks may require additional reporting elements as deemed necessary
by CDC.**

[Required activities]{.underline}

> 9.2a. Collect and transmit both case reports and supplemental
> surveillance information to CDC via the National Notifiable Diseases
> Surveillance System (NNDSS). Complete case reports and supplemental
> surveillance information should be submitted for all reported cases
> within one month of diagnosis. Cases of CRS, diphtheria, polio,
> rubella, measles, and pediatric (\<18 years of age) influenza deaths
> should be reported to CDC immediately by phone, with complete
> information submitted within one month. The total number of varicella
> outbreaks, defined as ≥5 cases related in place within at least one
> incubation period (i.e., 21 days), should be reported to CDC on a
> quarterly basis. For each varicella outbreak, the information to
> report should include: size of outbreak, age distribution, length of
> outbreak, vaccination coverage, and laboratory confirmation of cases,
> if obtained.
>
> *Performance Measure*: Percent of case reports submitted to CDC within
> one month of diagnosis
>
> *Target*: Set by individual program; progress toward 100%
>
> *Performance Measure*: Proportion of confirmed cases (measles,
> rubella, tetanus) or confirmed and probable cases (pertussis, mumps,
> diphtheria, varicella, varicella deaths, polio, Haemophilus influenzae
> \<5 years old, invasive Streptococcus pneumoniae \<5 years old,
> meningococcal disease, congenital rubella syndrome) that are reported
> through NNDSS with complete information, as indicated in CDC's "Manual
> for Surveillance of Vaccine-Preventable Diseases."
>
> *Target*: 90%

[Recommended activities]{.underline}

> 9.2b. Assure that laboratories report all results that indicate need
> for public health action, as described in CDC's "Manual for
> Surveillance of Vaccine-Preventable Diseases."
>
> 9.2c. Ensure that appropriate procedures exist and are followed for
> entering, analyzing, and reporting surveillance, investigation and
> outbreak data in a timely fashion.
>
> 9.2d. Analyze, review, and interpret surveillance data regularly and
> outbreak data as needed.
>
> 9.2e. Disseminate surveillance morbidity and mortality data regularly
> to surveillance partners, network participants, providers, policy
> makers, and the public.

**9.3 Evaluate timeliness and completeness of case/death investigation
and reporting, in accordance with CDC's "Manual for Surveillance of
Vaccine-Preventable Diseases."
<http://www.cdc.gov/nip/publications/surv-manual/default.htm>**

[Required activities]{.underline}

> 9.3a. Monitor the quality of VPD surveillance by reviewing
> surveillance indicators, problems identified, and strategies developed
> and implemented to address them.

-   For Haemophilus influenzae

> *Performance Measure*: The proportion of Haemophilus influenzae
> invasive disease cases among children \<5 years of age with complete
> vaccination history
>
> *Target*: 95%
>
> *Performance Measure*: The proportion of Haemophilus influenzae
> isolates from cases \<5 years of age that were serotyped
>
> *Target*: 95%

-   For measles

> *Performance Measure*: The proportion of measles cases with complete
> vaccination history
>
> *Target*: 100%
>
> *Performance Measure*: The proportion of measles cases or chains of
> transmission that have an imported source
>
> *Target*: 100%

-   For meningococcal disease

> *Performance Measure*: The proportion of cases with complete
> vaccination history
>
> *Target*: 95%
>
> *Performance Measure*: The proportion of meningococcal cases with
> known serogroup
>
> *Target*: 95%

-   For mumps

> *Performance Measure*: The proportion of mumps cases for which
> appropriate clinical specimens were obtained and submitted to the
> laboratory
>
> *Target*: 90%
>
> *Performance Measure*: The proportion of cases with complete
> vaccination history
>
> *Target*: 90%

-   For pertussis

> *Performance Measure*: The proportion of cases from which clinical
> specimens are obtained
>
> *Target*: 90%
>
> *Performance Measure*: The proportion of probable and confirmed
> pertussis cases meeting the clinical case definition that is
> laboratory confirmed
>
> *Target*: 90%
>
> *Performance Measure*: The proportion of cases confirmed by isolation
> of B pertussis by culture
>
> *Target*: At least 10%
>
> *Performance Measure*: The proportion of probable and confirmed
> pertussis cases with a complete vaccination history
>
> *Target*: 90%

-   For pneumococcal invasive disease

> *Performance Measure*: The proportion of pneumococcal invasive disease
> cases among children \<5 years of age with complete vaccination
> history
>
> *Target*: 95%
>
> *Performance Measure*: The proportion of pneumococcal isolates from
> cases of invasive disease \<5 years of age that are serotyped and
> tested for antibiotic resistance
>
> *Target*: 90%

-   For rubella

> *Performance Measure*: The proportion of confirmed rubella cases among
> women of child-bearing age with known pregnancy status
>
> *Target*: 100%
>
> *Performance Measure*: The proportion of confirmed rubella cases that
> are laboratory confirmed
>
> *Target*: 95%

-   For varicella

> *Performance Measure*: Percentage of cases with complete information
> for age, vaccination history, and severity of disease
>
> *Target*: 90% (contingent on availability of mechanism for reporting
> these data electronically through NNDSS)

[Recommended activities]{.underline}

> 9.3b. Monitor the quality of surveillance by applying surveillance
> indicators to additional VPDs.
>
> 9.3c. Monitor the quality of additional aspects of VPD surveillance by
> applying surveillance other indicators, as included in CDC's "Manual
> for Surveillance of Vaccine-Preventable Diseases."

**9.4 Coordinate reporting and monitor the Vaccine Adverse Event
Reporting System (VAERS) mandated by the National Childhood Vaccine
Injury Act of 1986.  The VAERS website now accepts adverse event reports
in an encrypted and secure electronic transmission format and can be
found at [www.vaers.hhs.gov](http://www.vaers.hhs.gov/).**

[Required activities]{.underline}

> 9.4a. Ensure at least one employee is designated with overall
> responsibility for vaccine safety and VAERS reporting. Duties should
> include completing VAERS reports electronically and/or in hard copy
> form, promptly reviewing all VAERS reports received, submitting
> reports to VAERS contractor within 7 days of receipt, requesting,
> collecting and forwarding supplemental medical information, answering
> provider and parent inquiries regarding VAERS and vaccine safety, and
> coordinating communication with and from media. Use state and local
> policies and procedures for VAERS reporting.

9.4b. Ensure all local health departments and public health clinics know
to report and report adverse events to the grantee using the VAERS form
and/or secure web-based reporting.

[Recommended activities]{.underline}

9.4c. Establish/maintain protocols and systems to accept reports of
adverse events following immunization; VAERS reports may be submitted by
public and private healthcare providers, parents, vaccinees, and other
concerned individuals.

> *Performance measure*: Increase in the number of adverse events
> reported to the immunization program office, by vaccine type and
> reporting source
>
> *Target*: Set by individual program
>
> *Performance measure*: Increase in the timeliness of reporting,
> measured by date of report minus date of symptom onset
>
> *Target*: Set by individual program

9.4d. Provide all immunization providers (public and private) with a
copy of state policies on VAERS reporting, copies of the VAERS reporting
form, instructions on which adverse events must be reported and which
can be reported, instructions on completing and submitting the form, and
updates on VAERS reporting as they arise.

> *Performance measure*: Number of newly licensed providers (e.g.,
> pediatricians, family practitioners, general practitioners, clinics)
> and percentage of those provided VAERS and other safety information
> and training
>
> *Target*: \>90%; set by individual program
>
> 9.4e. Encourage providers to voluntarily submit VAERS reports on
> adverse events not listed in the National Vaccine Injury Table.
>
> 9.4f. Communicate information on vaccine safety in a timely way to all
> healthcare providers, public health officials, state professional
> associations, and the public, using tools including media interviews,
> press releases, information kits, etc.

**9.5 Follow up on all reports of serious adverse events received by the
state agency (e.g., death, life-threatening illness, hospitalization and
permanent disability) following immunization.**

[Required activities]{.underline}

9.5a. Routinely obtain supplemental medical information (e.g., autopsy
reports, death certificates, hospital discharge summaries) related to
every serious adverse event reported (e.g., reports involving death,
life-threatening illness, hospitalization, permanent disability).

> *Performance measure:* Number and percentage of serious adverse event
> reports for which supplemental medical information was collected
>
> *Target*: \>90%; set by individual program

9.5b. Submit supplemental medical information requested by the national
VAERS program within 10 working days of receipt of request.

> *Performance measure:* Number and percentage of requested supplemental
> reports submitted within 10 working days of receipt of request
>
> *Target:* \>90%; set by individual program

[Recommended activities]{.underline}

9.5c. Review all VAERS reports that are sent to the state agency upon
receipt; verify accuracy of key information designated with "boxes" on
form, attempt to complete critical fields, and assign an immunization
project number. If all critical information cannot be obtained by the
grantee, the report should be forwarded to VAERS if it contains at least
the following: a patient identifier (nominal or non-nominal); a vaccine;
an adverse event description; and an identifiable reporter (of the
adverse event).

> *Performance measure*: Number and percentage of VAERS reports
> submitted to the contractor within 5 working days of receipt
>
> *Target*: \>90%; set by individual program

**9.6 Additional Activities**

[Recommended activities]{.underline}

> 9.6a. Collaborate with local/state influenza surveillance coordinators
> to ensure adequate local and state influenza surveillance, including
> virologic surveillance and outpatient surveillance for influenza-like
> illness. Develop plans for timely and coordinated dissemination of
> influenza vaccination promotions. Ensure that state and local
> influenza virus surveillance data are disseminated to providers and
> the public during each influenza season.

9.6b. Surveillance Information Systems funded through the Immunization
Services Division (ISD), like all systems funded through CDC grants,
contracts, and cooperative agreements, must comply with the Public
Health Information Network (PHIN) standards and specifications.
<http://www.cdc.gov/phin/overview.html>

> 9.6c. Assure prenatal screening of all pregnant women for rubella
> antibody and documentation of results in provider and birthing
> hospital chart.
>
> *Performance Measure*: Number and percent of pregnant women with
> documentation of rubella status in pre-delivery hospital record
>
> *Target*: Set by individual program; progress toward 100%
>
> 9.6d. Assure rubella antibody-negative mothers are made aware of
> benefits and risks of rubella vaccine, offered rubella vaccine
> following delivery, and acceptors receive the vaccine before hospital
> discharge.
>
> *Performance Measure*: Number and percent of rubella antibody-negative
> pregnant women receiving rubella vaccine following delivery and prior
> to discharge
>
> *Target*: Set by individual program; progress toward 100%
>
> 9.6e. Maintain a registry of persons with HBsAg-positive results.