VAERS Data & Statistics
Summary statistics from the Vaccine Adverse Event Reporting System public data files
About VAERS Data
VAERS (Vaccine Adverse Event Reporting System) is a national passive surveillance system managed jointly by the CDC and FDA. This page presents summary statistics from VAERS public data files. All figures reflect reports submitted to VAERS and do not represent confirmed causal relationships between vaccines and adverse events.
VAERS data is publicly available at vaers.hhs.gov. Raw data files are updated weekly.
Understanding VAERS Numbers
Key limitations readers must understand when interpreting VAERS data:
Reports Are Not Confirmed Injuries
A VAERS report means someone reported an event after vaccination. It does not mean the vaccine caused the event. Anyone can file a report, including patients, healthcare providers, and manufacturers.
Underreporting Is Common
Studies estimate VAERS captures between 1% and 10% of actual adverse events. Serious events are more likely to be reported than mild ones.
Overreporting Also Occurs
During periods of heightened media attention (e.g. COVID-19 vaccine rollout), reporting rates increase significantly — including reports of events with no plausible biological connection to vaccination.
No Denominator Is Provided
VAERS totals cannot be converted to rates without knowing total doses administered. Raw report counts alone do not indicate risk level.
Annual Report Volumes
Key figures from VAERS public data (2021–2023):
Approximately 1,000,000 reports submitted — the highest annual total in VAERS history, driven by COVID-19 vaccine rollout and mandatory healthcare worker reporting requirements.
Approximately 500,000 reports submitted as COVID-19 booster reporting stabilised.
Approximately 200,000 reports submitted, returning closer to pre-pandemic baseline levels.
Note: Pre-2021 annual totals averaged 50,000–70,000 reports per year across all vaccines.
Most Reported Event Categories
Consistently reported event types across all vaccines (not specific to any single product):
- Injection site reactions (pain, redness, swelling)
- Systemic reactions (fever, fatigue, headache)
- Allergic reactions (ranging from mild rash to anaphylaxis)
- Syncope (fainting) — most common in adolescents
- Guillain-Barré Syndrome (GBS) — monitored across multiple vaccines
- Myocarditis/pericarditis — monitored specifically for mRNA vaccines
How to Access VAERS Data
VAERS public data is available through three primary access methods:
VAERS Wonder Database
CDC's online query tool. Allows filtering by vaccine, event type, age group, and year. No download required.
wonder.cdc.gov/vaers.html →VAERS Data Files
Raw CSV files updated weekly. Requires data analysis skills. Available for download from the official VAERS site.
vaers.hhs.gov/data →MedAlerts (Third Party)
Independent search interface for VAERS data maintained by the National Vaccine Information Center. Useful for quick searches.
medalerts.org →Data Updates
VAERS data files are updated weekly. There is typically a 2-4 week lag in processing new reports.
Sources & Citations
- CDC/FDA. VAERS Public Data Files. vaers.hhs.gov, updated weekly.
- Shimabukuro TT et al. "Safety monitoring in the Vaccine Adverse Event Reporting System (VAERS)." Vaccine, 2015.
- Hazell L, Shakir SA. "Under-reporting of adverse drug reactions." Drug Safety, 2006.
- CDC. VAERS Guide to Interpreting VAERS Data. cdc.gov/vaccinesafety.