Loading…
Postlicensure Safety Surveillance for Varicella Vaccine
CONTEXT Since its licensure in 1995, the extensive use of varicella vaccine and close surveillance of the associated anecdotal reports of suspected adverse effects provide the opportunity to detect potential risks not observed before licensure because of the relatively small sample size and other li...
Saved in:
Published in: | JAMA : the journal of the American Medical Association 2000-09, Vol.284 (10), p.1271-1279 |
---|---|
Main Authors: | , , , , , , |
Format: | Article |
Language: | English |
Subjects: | |
Citations: | Items that cite this one |
Online Access: | Get full text |
Tags: |
Add Tag
No Tags, Be the first to tag this record!
|
Summary: | CONTEXT Since its licensure in 1995, the extensive use of varicella vaccine
and close surveillance of the associated anecdotal reports of suspected adverse
effects provide the opportunity to detect potential risks not observed before
licensure because of the relatively small sample size and other limitations
of clinical trials. OBJECTIVES To detect potential hazards, including rare events, associated with
varicella vaccine, and to assess case reports for clinical and epidemiological
implications. DESIGN AND SETTING Postlicensure case-series study of suspected vaccine adverse events
reported to the US Vaccine Adverse Event Reporting System (VAERS) from March
17, 1995, through July 25, 1998. MAIN OUTCOME MEASURES Numbers of reported adverse events, proportions, and reporting rates
(reports per 100,000 doses distributed). RESULTS VAERS received 6574 case reports of adverse events in recipients of
varicella vaccine, a rate of 67.5 reports per 100,000 doses sold. Approximately
4% of reports described serious adverse events, including 14 deaths. The most
frequently reported adverse events were rashes, possible vaccine failures,
and injection site reactions. Misinterpretation of varicella serology after
vaccination appeared to account for 17% of reports of possible vaccine failures.
Among 251 patients with herpes zoster, 14 had the vaccine strain of varicella
zoster virus (VZV), while 12 had the wild-type virus. None of 30 anaphylaxis
cases was fatal. An immunodeficient patient with pneumonia had the vaccine
strain of VZV in a lung biopsy. Pregnant women occasionally received varicella
vaccine through confusion with varicella zoster immunoglobulin. Although the
role of varicella vaccine remained unproven in most serious adverse event
reports, there were a few positive rechallenge reports and consistency of
many cases with syndromes recognized as complications of natural varicella. CONCLUSION Most of the reported adverse events associated with varicella vaccine
are minor, and serious risks appear to be rare. We could not confirm a vaccine
etiology for most of the reported serious events; several will require further
study to clarify whether varicella vaccine plays a role. Education is needed
to ensure appropriate use of varicella serologic assays and to eliminate confusion
between varicella vaccine and varicella zoster immunoglobulin. |
---|---|
ISSN: | 0098-7484 1538-3598 |
DOI: | 10.1001/jama.284.10.1271 |