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.
The COVID-19 pandemic fundamentally changed vaccine adverse event reporting. In 2021, VAERS received more reports than in the previous decade combined.
Between 1990 and 2019, VAERS received an average of about 40,051 reports per year. Then came 2021. With the largest mass vaccination campaign in U.S. history, VAERS received 768,706 reports in a single year — more than the entire period from 2005 to 2015 combined.
The COVID-19 era (1,071,696 reports from 2020-2022) accounts for roughly 54% of all VAERS reports ever submitted. This is a staggering concentration, but context is essential to understanding it.
Several factors drove the unprecedented surge:
COVID-19 vaccine reports are dominated by the two mRNA vaccines. The combined COVID-19 vaccine category has 1,121,388 total reports, making it by far the largest single vaccine category in VAERS history.
Pfizer-BioNTech and Moderna together account for over 92% of all COVID-19 vaccine VAERS reports. This reflects their dominant market share — they administered the vast majority of doses. Janssen (Johnson & Johnson) has a smaller share, partly because its single-dose regimen was less widely used and was later deprioritized.
It's tempting to look at these numbers and draw conclusions about vaccine safety. But the most important number is the one VAERS doesn't provide: the denominator.
With 670+ million doses administered, a report rate of roughly 1,000 per million doses puts COVID-19 vaccines in line with historical VAERS reporting rates for other widely-administered vaccines. The raw numbers are large because the number of doses was unprecedented.
As VAERS reporting normalizes following the COVID-19 pandemic surge, the data landscape for COVID-19 impact on VAERS reporting is shifting. Annual VAERS reports in 2025-2026 have returned to the 35,000-45,000 range typical of the pre-pandemic era (2015-2019), making year-over-year comparisons more meaningful again.
The HHS administration has signaled increased focus on vaccine safety data analysis, including the development of AI-powered tools for pattern detection in VAERS reports. While these tools are still under development, they represent a potential evolution in how adverse event data is analyzed and interpreted.
New vaccines entering the market — including RSV vaccines for older adults and pregnant women, updated COVID-19 formulations, and potential H5N1 avian flu vaccines — continue to add new data streams to VAERS. Each new vaccine type provides additional context for understanding COVID-19 impact on VAERS reporting across the full spectrum of vaccine safety surveillance.
This analysis is based entirely on VAERS passive surveillance data, which carries important limitations that must be understood:
For these reasons, VAERS data is best used for signal detection — identifying potential safety concerns that warrant further investigation — rather than for definitive risk assessment. When VAERS surfaces a potential signal, it is investigated using more rigorous systems like the Vaccine Safety Datalink (VSD) and controlled epidemiological studies.
All data on VaccineWatch comes from the official VAERS public-use datasets published by the CDC and FDA. Our current dataset covers reports from 1990 through early 2026. We process the raw data without filtering or editorializing — every metric is a transparent aggregation of official government data.
As VAERS reporting normalizes following the COVID-19 pandemic surge, the data landscape for COVID-19 impact on VAERS reporting is shifting. Annual VAERS reports in 2025-2026 have returned to the 35,000-45,000 range typical of the pre-pandemic era (2015-2019), making year-over-year comparisons more meaningful again.
The HHS administration has signaled increased focus on vaccine safety data analysis, including the development of AI-powered tools for pattern detection in VAERS reports. While these tools are still under development, they represent a potential evolution in how adverse event data is analyzed and interpreted.
New vaccines entering the market — including RSV vaccines for older adults and pregnant women, updated COVID-19 formulations, and potential H5N1 avian flu vaccines — continue to add new data streams to VAERS. Each new vaccine type provides additional context for understanding COVID-19 impact on VAERS reporting across the full spectrum of vaccine safety surveillance.
This analysis is based entirely on VAERS passive surveillance data, which carries important limitations that must be understood:
For these reasons, VAERS data is best used for signal detection — identifying potential safety concerns that warrant further investigation — rather than for definitive risk assessment. When VAERS surfaces a potential signal, it is investigated using more rigorous systems like the Vaccine Safety Datalink (VSD) and controlled epidemiological studies.
All data on VaccineWatch comes from the official VAERS public-use datasets published by the CDC and FDA. Our current dataset covers reports from 1990 through early 2026. We process the raw data without filtering or editorializing — every metric is a transparent aggregation of official government data.