The Vaccine Adverse Event Reporting System is a United States program for vaccine safety, co-managed by the Centers for Disease Control and Prevention (CDC) and the Food and Drug Administration (FDA). VAERS is a post-marketing safety surveillance program, collecting information about adverse events (possible side effects) that occur after administration of vaccines. VAERS has several limitations, including unverified reports, underreporting, inconsistent data quality, and absence of an unvaccinated control group.

Origins

The program is an outgrowth of the 1986 National Childhood Vaccine Injury Act (NCVIA), which requires health care providers to report:

• Any event listed by the vaccine manufacturer as a contraindication to subsequent doses of the vaccine.
• Any event listed in the Reportable Events Table that occurs within the specified time period after vaccination. The data are stored electronically by the CDC in the Vaccine Safety Datalink (VSD).

VAERS was established in 1990, and is managed jointly by the FDA and the CDC. It is meant to act as a sort of "early warning system"—a way for physicians and researchers to identify possible unforeseen reactions or side effects of vaccination for further study.