The Vaccine Adverse Events Reporting System (VAERS) is a national database that collects information about possible side effects that occur after a (U.S.-licensed) vaccine is given.
The system gets reports from healthcare providers, patients, parents, or anyone who witnessed or even just heard of a possible adverse reaction that occurred after getting any vaccine. The public can view VAERS reports. The VAERS website also shares vaccine safety-related information with parents/guardians, health care providers, vaccine manufacturers, state vaccine programs, and others.
But, VAERS reports can be difficult to understand and have often been misinterpreted. Sometimes VAERS is credited as the source of information spread by people who oppose vaccines, especially during the COVID-19 pandemic.
The video below provides an overview of the VAERS database and its limitations. Importantly, a VAERS report does not mean the vaccine caused the reaction or outcome. It only means that the vaccination happened first. VAERS is set up to help scientists notice trends or reasons they should investigate a possible problem. It is not a list of verified outcomes of vaccination.