Vaccine Adverse Event Reporting System

The Vaccine Adverse Event Reporting System (VAERS) is a United States program for vaccine safety, co-managed by the U.S. Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA).^[1] VAERS is a postmarketing surveillance program, collecting information about adverse events (possible harmful side effects) that occur after administration of vaccines to ascertain whether the risk–benefit ratio is high enough to justify continued use of any particular vaccine.

VAERS, the Vaccine Safety Datalink, and the Clinical Immunization Safety Assessment (CISA) Network are tools by which the CDC and FDA monitor vaccine safety^[2] to fulfill their duty as regulatory agencies charged with protecting the public.

As it is based on submissions by the public, VAERS is susceptible to unverified reports, misattribution, underreporting, and inconsistent data quality.^[3] Raw, unverified data from VAERS has often been used by the anti-vaccine community to justify misinformation regarding the safety of vaccines; it is generally not possible to find out from VAERS data if a vaccine caused an adverse event, or how common the event might be.^[4]