Vaccine Safety
> Clinical Immunization Safety Assessment
CISA:
Improving the Evaluation,
Management and Understanding of Adverse Events Possibly Related to
Immunizations
By
Robert Pless, MD, MSc; Christine Casey, MD; Robert Chen, MD, MA (Chief);
Vaccine Safety and Development Activity, Epidemiology and Surveillance
Division (ESD), National Immunization Program (NIP), Centers for Disease
Control and Prevention (CDC)
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Vaccines
are among the most widely used and effective public health interventions
for preventing disease, and among the safest medical products available.
But as tlie incidence of life-threatening, vaccine preventable diseases
has decreased, rare adverse events following immunization have received
increased attention by both parents and health care providers, leading
some parents to withhold vaccinations for their children. Close
monitoring and timely assessment of suspected vaccine adverse events
are critical to prevent loss of confidence, decreased vaccine coverage
and the return of epidemic disease.
Clinical
Immunization Safety Assessment (CISA) centers are a new initiative
designed to improve the scientific understanding of vaccine safety
at the individual "patient" level. A network comprised
of clinical academic centers in partnership with tlie Centers for
Disease Control and Prevention (CDC) serves as a source of clinical
expertise in evaluating and treating adverse events following immunization.
Data from the CISA centers are expected to provide insight into
preventing the occurrence of vaccine-related adverse events.
Prior
to the creation of the CISA network, no coordinated facilities existed
in the U.S. that investigated and managed adverse events on an individual
level for the purpose of systematically collecting and evaluating
those incidents. This void has previously left parents, patients
and health care providers on their own to find answers and/or treatments
for adverse events.
Clinically
significant adverse events occur rarely, but CISA centers are working
to improve the understanding of these events. Through participation
in the CISA network and with the CDC, medical and professional staff
with expertise in vaccine safety will systematically evaluate cases
of adverse events reported to die Vaccine Adverse Event Reporting
System (VAERS). VAERS is the national passive surveillance system
for adverse events following immunization, which receives reports
from health care providers and the public. Selected cases will undergo
enhanced follow up and targeted clinical evaluation to better understand
the mechanism(s) and risk factors for the event. Health care providers
will also be able to refer patients to a CISA center for a consultation,
either by filing a VAERS report and including a specific request,
or through usual consultation mechanisms already in place at the
institutions with which a center is affiliated. The results of these
evaluations will be used to develop clinical evaluation protocols
or patient management guidelines that can be used by all health
care providers.
The
network's goals are to:
-
Develop clinical protocols for the evaluation and management of
adverse events possibly related to immunization, and disseminate
them through professional publications or other appropriate mechanisms.
-
Evaluate groups of patients witli similar adverse events, using
a standard
protocol, in order to elucidate the mechanism(s) by which these
unusual or severe adverse reactions occur. Through evaluation,
genetic or other risk factors that predispose to these reactions
may be determined.
-
Provide immunization guidelines and clinical management protocols
for patients who have had an adverse reaction that may not contraindicate
further vaccination but where there is concern regarding continuation
of the particular vaccine series.
-
Serve as a public and provider regional referral center for clinical
vaccine safety inquiries.
In
the United States immunization safety system, CISA centers will
serve as an intermediate step between passive reporting of individual
cases of adverse events with no or minimal follow-up, and more rigorous
epidemiological investigations into vaccine safety, such as tlie
use of large linked databases, clinical trials and case-control
or cohort studies. These goals will help to better define tlie level
of risk of an adverse event for the individual patient, identify
areas for additional scientific investigation to keep vaccines safe
and lielp maintain the public's confidence in immunization.
The
first group of CISA centers was funded in October 2001, and has
begun the process of coordinating their activities and establishing
mechanisms by which adverse event cases reported to VAERS will be
reviewed, and clinical evaluations defined and performed. They include
Johns Hopkins University partnering with specialists at tlie University
of Maryland, in Baltimore; Northern California Kaiser with collaborators
at Stanford University in San Francisco, California; Vanderbilt
University in Nashville, Tennessee; Boston University Medical Center
in Boston, Massachusetts; and Columbia Presbyterian Hospital in
New York City, New York.
For
more information on CISA centers and other vaccine safety activities,
please contact the Vaccine Safety and Development Activity Desk
at (404) 639-8256.
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