About VaccineWatch
Transparent access to VAERS data for informed decision-making. Neither pro-vaccine nor anti-vaccine — pro-transparency.
Our Mission
VaccineWatch exists to make publicly available vaccine safety data accessible, understandable, and contextualized. We believe that data transparency is essential for public trust, and that raw numbers need proper framing to be informative rather than misleading.
What is VAERS?
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).
Established in 1990, VAERS collects reports of adverse events (possible side effects) that occur after vaccination. Anyone can report an adverse event to VAERS — healthcare professionals, vaccine manufacturers, and the public. Healthcare providers are required by law to report certain adverse events following vaccination.
VAERS serves as one of several systems used to monitor vaccine safety. It is designed to detect possible signals that may indicate a potential safety concern, which can then be studied further through more rigorous methods.
What We Cover
How to Use This Site
🧬 Explore Vaccines
Browse all 104 vaccine types in VAERS. See reports, outcomes, yearly trends, and associated symptoms for each vaccine.
Browse Vaccines →🩺 Research Symptoms
Search through 500 reported symptoms. See which vaccines are most associated with each symptom and severity statistics.
Browse Symptoms →⚖️ Compare Vaccines
Compare 2-3 vaccines side by side. See how their report counts, outcomes, and yearly trends differ.
Compare Tool →📊 Read Analysis
23 in-depth articles provide context-rich exploration of VAERS data, including COVID impact, age patterns, myocarditis, and more.
Read Analysis →Data Methodology
VaccineWatch processes raw VAERS data files published by the CDC/FDA. Our methodology includes:
- Data source: Official VAERS CSV data files from vaers.hhs.gov
- Time range: 1990 through February 2026 (the most recent available data)
- Processing: We aggregate raw reports by vaccine type, symptom, manufacturer, state, age group, and gender
- Categorization: Outcomes are categorized based on VAERS-defined fields: died, hospitalized, ER visit, disabled, life-threatening
- No filtering: We include all reports as-is. We do not remove or filter any reports
- No interpretation: We present aggregate counts without making causal claims
Update Frequency
The VAERS database is updated approximately quarterly by the CDC/FDA. We process new data releases as they become available. The current dataset was last updated on February 25, 2026.
Data Processing Pipeline
- Download — Raw CSV files from the VAERS website (VAERSDATA, VAERSVAX, VAERSSYMPTOMS)
- Parse — Extract and normalize fields, handle encoding issues and inconsistencies
- Aggregate — Group by vaccine type, symptom, manufacturer, state, age, gender, year
- Cross-reference — Link vaccine-symptom pairs, create relationship maps
- Publish — Generate static JSON files for fast, serverless delivery
Limitations of VAERS Data
Understanding these limitations is essential for interpreting VAERS data correctly.
Misinterpretation of VAERS data is common and can lead to unfounded conclusions. Please read these limitations carefully before drawing any conclusions from the data on this site.
Reports Do Not Prove Causation
A VAERS report indicates that an adverse event occurred after vaccination. It does not mean the vaccine caused the event. The event could be coincidental, related to an underlying condition, or caused by something else entirely.
Underreporting and Overreporting
VAERS is a passive reporting system. Not all adverse events are reported (underreporting), and some events may be reported that are unrelated to vaccination. During periods of heightened awareness (like the COVID-19 pandemic), reporting rates may increase significantly (stimulated reporting).
Unverified Information
VAERS reports may contain information that is incomplete, inaccurate, coincidental, or unverifiable. Reports are not verified for accuracy before being accepted into the database.
No Denominator Data
VAERS does not include data on how many people received each vaccine. Without this denominator, you cannot calculate a rate or risk. A vaccine with 10,000 reports and 100 million doses is very different from one with 10,000 reports and 1 million doses.
Anyone Can Report
Reports can be filed by anyone — doctors, patients, family members, lawyers, or anyone else. The quality and accuracy of reports varies widely. Some reports may be submitted to support legal claims or advocacy positions.
Duplicate Reports
The same event may be reported multiple times by different reporters (e.g., a doctor and a family member both report the same event). VAERS attempts to identify duplicates but some may remain in the data.
VAERS in Context: Other Safety Systems
VAERS is just one of several systems used to monitor vaccine safety. Others include:
- • Vaccine Safety Datalink (VSD) — Active surveillance using electronic health records from 9 healthcare organizations
- • Clinical Immunization Safety Assessment (CISA) — Expert evaluation of complex adverse events
- • v-safe — Smartphone-based active monitoring (used for COVID-19 vaccines)
- • Post-licensure studies — Formal epidemiological studies to investigate safety signals
VAERS excels at detecting potential signals quickly but lacks the rigor to confirm causation. That's by design — it's an early warning system, not a definitive study.
Built by TheDataProject.ai
VaccineWatch is part of a portfolio of data-driven transparency tools built by TheDataProject.ai. Our mission is to make government data accessible, understandable, and useful for everyone.
VaccineWatch is committed to presenting VAERS data transparently and responsibly. We are neither pro-vaccine nor anti-vaccine — we are pro-transparency.
For medical decisions, always consult with qualified healthcare professionals.