Important: VAERS reports alone cannot determine if a vaccine caused an adverse event. Reports may contain incomplete, inaccurate, or unverified information. Correlation does not equal causation.
A data-driven look at vaccine safety through the lens of 1,983,260 adverse event reports across 104 vaccines spanning 35 years. We present the numbers with context, because raw data without interpretation is easily misunderstood.
Vaccines are among the most studied medical interventions in history. Before approval, they undergo years of clinical trials involving thousands of participants. After approval, multiple monitoring systems — including VAERS — continuously track their safety.
VAERS is one piece of this puzzle. It's an early warning system designed to detect potential safety signals. It's not designed to prove or disprove that vaccines cause specific adverse events. That distinction is critical for understanding the data on this site.
Across 35 years and billions of vaccine doses, VAERS has collected about 2 million reports. The vast majority describe mild, expected reactions:
Serious outcomes represent a small fraction. Of all reports, about 7.2% involved hospitalization and 1.4% mentioned death. But these percentages are not risk rates — they're artifacts of a passive reporting system with known biases. See our denominator problem analysis for why.
Three critical limitations make raw VAERS numbers unreliable for determining vaccine risk:
Different vaccines have different safety profiles. Explore detailed VAERS data for specific vaccines:
When assessing vaccine safety, look beyond VAERS alone:
VAERS is just one tool in a comprehensive safety monitoring ecosystem. It's the most accessible to the public, which is why sites like VaccineWatch exist — to help you understand what the data means.