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Vaccine Adverse Event Reporting System


VAERS is a national post-marketing vaccine safety surveillance program cosponsored. VAERS collects information about adverse events (possible side effects) that occur after the administration of vaccines licensed in the U.S. It provides a nationwide mechanism by which adverse events following immunization may be reported, analyzed, and made available to the public. It also provides a vehicle for disseminating vaccine safety related information to parents and guardians, healthcare providers, vaccine manufacturers, state vaccination programs, and other constituencies.

Data Years Available: 
Mode of Collection: 
Voluntary submission of reports.
Selected Content: 
Information can be accessed on symptoms, vaccine products, adverse event characteristics, manufacturers, patient characteristics, vaccination date, report date, and patient outcome.
Population Covered: 
VAERS seeks reports of any clinically significant medical event that occurs after vaccination, even if the reporter cannot be certain that the event was caused by the vaccine. CDC/Immunization Safety Office (ISO) and the Food and Drug Administration (FDA) review adverse reports; VAERS has identified important signals that after further research resulted in changes to vaccine recommendations. The majority of VAERS reports are sent in by vaccine manufacturers (37%) and health care providers (36%). The remaining reports are obtained from state immunization programs (10%), vaccine recipients (or their parent/guardians, 7%) and other sources (10%).
Response Rates and Sample Size: 
Interpretation Issues: 
When evaluating data from VAERS, it is important to note that for any reported event, no cause-and-effect relationship has been established.