How do the FDA and the CDC monitor the safety of vaccines after they are licensed?
There are 3 systems used to monitor the safety of vaccines after they are licensed and being used in the U.S. These systems can monitor side effects already known to be caused by vaccines as well as detect rare side effects that were not identified during a vaccine’s clinical trials. • The Vaccine Adverse Event Reporting System (VAERS) receives reports of possible vaccine side effects, called “adverse events”, by regular mail, fax, or through the web. Reports can be made by doctors, parents, or family members, someone who got a vaccine, or by a manufacturer. Reports can be submitted at any time after someone gets a vaccine. This means a person can report a health problem that develops months or even years after they get a vaccine. All reports are reviewed by trained staff at both FDA and CDC. VAERS can detect patterns in reports to show that a vaccine might be causing a possible side effect. It cannot be used to determine for sure if the vaccine really is causing a side effect. • The V
