Vaccine Adverse Event Reporting System
Vaccines are developed with the highest standards of safety. However, as with any medical procedure, vaccination has some risks. Individuals react differently to vaccines, and there is no way to predict how individuals will react to a particular vaccine.
The National Childhood Vaccine Injury Act (NCVIA) requires health care providers to report adverse events (possible side effects) that occur following vaccination, so the Food and Drug Administration (FDA) External Web Site Icon and Centers for Disease Control and Prevention (CDC) established the Vaccine Adverse Events Reporting System (VAERS) External Web Site Icon in 1990. VAERS is a national passive reporting system that accepts reports from the public on adverse events associated with vaccines licensed in the United States. VAERS data are monitored to–
- Detect new, unusual, or rare vaccine adverse events
- Monitor increases in known adverse events
- Identify potential patient risk factors for particular types of adverse events
- Identify vaccine lots with increased numbers or types of reported adverse events
- Assess the safety of newly licensed vaccines
Approximately 30,000 VAERS reports are filed annually, with 10-15% classified as serious (resulting in permanent disability, hospitalization, life-threatening illnesses or death). Anyone can file a VAERS report, including health care providers, manufacturers, and vaccine recipients or their parents or guardians. The VAERS form requests the following information:
- The type of vaccine received
- The timing of the vaccination
- The onset of the adverse event
- Current illnesses or medication
- Past history of adverse events following vaccination
- Demographic information about the recipient
A contractor, under the supervision of FDA and CDC, enters the information from VAERS forms into a database. Those reporting an adverse event to VAERS receive a confirmation letter containing a VAERS identification number. Additional information may be submitted to VAERS using the assigned identification number. Selected cases of serious adverse reactions are followed up at 60 days and one-year post-vaccination to check the recovery status of the patient. FDA and CDC use VAERS data to monitor vaccine safety and conduct research studies. VAERS data (without identifying personal information) are also available to the public.
While VAERS provides useful information on vaccine safety, the data are somewhat limited. For example, VAERS reports may provide incomplete information. Specifically, judgments about whether the vaccine was truly responsible for an adverse event cannot be made from VAERS reports.