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.
How many adverse event reports are filed per dose of vaccine administered? This tool combines VAERS report counts with CDC dose administration estimates to calculate reporting rates per million doses — the single most important context missing from raw VAERS numbers.
Raw VAERS report counts are misleading without knowing how many people received each vaccine. A vaccine with 100,000 reports given to 500 million people has a very different risk profile than one with 10,000 reports given to 5 million people. Reporting rates provide that critical context.
We divide the number of VAERS reports by the estimated total doses administered to get a rate per million doses. Dose estimates come from CDC published data: COVID Data Tracker for COVID vaccines, FluVaxView for influenza, and National Immunization Survey (NIS) coverage rates multiplied by birth cohort sizes for childhood vaccines.
The denominator problem is the single biggest issue in interpreting VAERS data. Without knowing how many doses were given, you cannot compare vaccines fairly. COVID vaccines have the most VAERS reports in history — but they were also given to more Americans in a shorter period than any vaccine ever. The reporting rate per dose tells a very different story than the raw numbers.