The Vaccine Adverse Event Reporting System (VAERS) is a national early warning system to detect possible safety problems in U.S.-licensed vaccines. VAERS is co-managed by the Centers for Disease Control and Prevention (CDC) and the U.S. Food and Drug Administration (FDA).
What does VAERS do?
VAERS accepts and analyzes reports of adverse events (possible side effects) after a person has received a vaccination. Anyone can
report an adverse event to VAERS. Healthcare professionals are required to report certain adverse events and vaccine manufacturers are required to report all adverse events that come to their attention.
VAERS relies on individuals to send in reports of their experiences. VAERS is not designed to determine if a vaccine caused a health problem, but is especially useful for detecting unusual or unexpected patterns of adverse event reporting that might indicate a possible safety problem with a vaccine. This way, VAERS can provide CDC and FDA with valuable information that additional work and evaluation is necessary to further assess a possible safety concern.
Objectives of VAERS
The primary objectives of VAERS are 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;
- Assess the safety of newly licensed vaccines;
- Determine and address possible reporting clusters (e.g., suspected localized [temporally or geographically] or product-/batch-/lot-specific adverse event reporting);
- Recognize persistent safe-use problems and administration errors;
- Provide a national safety monitoring system that extends to the entire general population for response to public health emergencies, such as a large-scale pandemic influenza vaccination program.
VAERS Data
VAERS data is accessible by downloading raw data in comma-separated value (CSV) files for import into a database, spreadsheet, or text editing program, or by using the CDC WONDER online search tool. Information provided to VAERS which identifies a person who received the vaccine or vaccines will not be made available to the public.
Learn more about accessing VAERS data.
