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.
- Centers for Disease Control and Prevention (CDC)
- Food and Drug Administration (FDA)
Questionable source (Data limitations)
Reports of all possible associations between vaccines and adverse events are filed in VAERS. VAERS collects data on any adverse event following vaccination, be it coincidental or truly caused by a vaccine. VAERS is a passive reporting system. VAERS reports can be submitted voluntarily by anyone, including healthcare providers, patients, or family members. Reports vary in quality and completeness. They often lack details and sometimes can have information that contains errors. "Underreporting" is one of the main limitations of passive surveillance systems, including VAERS. The degree of underreporting varies widely. As an example, a great many of the millions of vaccinations administered each year by injection cause soreness, but relatively few of these episodes lead to a VAERS report. Physicians and patients understand that minor side effects of vaccinations often include this kind of discomfort, as well as low fevers. On the other hand, more serious and unexpected medical events are probably more likely to be reported than minor ones, especially when they occur soon after vaccination, even if they may be coincidental and related to other causes.
Data Years Available
Voluntary submission of reports.
Information can be accessed on symptoms, vaccine products, adverse event characteristics, manufacturers, patient characteristics, vaccination date, report date, and patient outcome.
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%).
When evaluating data from VAERS, it is important to note that for any reported event, no cause-and-effect relationship has been established.