VAERS CDC Disclaimer

VAERS accepts reports of adverse events and reactions that occur following vaccination. Healthcare providers, vaccine manufacturers, and the public can submit reports to the system. While very important in monitoring vaccine safety, VAERS reports alone cannot be used to determine if a vaccine caused or contributed to an adverse event or illness. The reports may contain information that is incomplete, inaccurate, coincidental, or unverifiable. In large part, reports to VAERS are voluntary, which means they are subject to biases. This creates specific limitations on how the data can be used scientifically. Data from VAERS reports should always be interpreted with these limitations in mind.

The strengths of VAERS are that it is national in scope and can quickly provide an early warning of a safety problem with a vaccine. As part of CDC and FDA’s multi-system approach to post-licensure vaccine safety monitoring, VAERS is designed to rapidly detect unusual or unexpected patterns of adverse events, also known as “safety signals.” If a safety signal is found in VAERS, further studies can be done in safety systems such as the CDC’s Vaccine Safety Datalink (VSD) or the Clinical Immunization Safety Assessment (CISA) project. These systems do not have the same scientific limitations as VAERS, and can better assess health risks and possible connections between adverse events and a vaccine.

Key considerations and limitations of VAERS data:

Vaccine providers are encouraged to report any clinically significant health problem following vaccination to VAERS, whether or not they believe the vaccine was the cause.

Reports may include incomplete, inaccurate, coincidental and unverified information.

The number of reports alone cannot be interpreted or used to reach conclusions about the existence, severity, frequency, or rates of problems associated with vaccines.

VAERS data is limited to vaccine adverse event reports received between 1990 and the most recent date for which data are available.

VAERS data do not represent all known safety information for a vaccine and should be interpreted in the context of other scientific information.

VAERS data available to the public include only the initial report data to VAERS. Updated data which contains data from medical records and corrections reported during follow up are used by the government for analysis. However, for numerous reasons including data consistency, these amended data are not available to the public.

COVID-19 Vaccine Lots

For Pfizer, Moderna and Janssen(J&J) vaccines.

Are some batches of Covid-19 vaccines more dangerous than others? Previously it was impossible to determine the Serious Adverse Event (SAE) rate by lot number because we did not know the total number of doses in the lot ("the denominator"). So the Informed Consent Action Network via the extraordinary attorneys Siri & Glimstad LLP used the Freedom of Information Act to obtain from the CDC the full data set of doses shipped in the US and territories by lot number. As you will see below, we can now confirm that some batches of Covid-19 vaccines are significantly more dangerous than others.

To find out more about the lot data and how it was prepared-read our FAQ.

You can also search the data yourself by lot number or state.

"All SAE's" are defined as: ER visits, hospitalizations, permanent disability, life threatening, deaths and birth defects.

Where we use Date this means: First date shipped. In most cases all shipments occurred within 2-4 weeks. In a few cases the lots shipped in under 4 months.

On the scatterplot charts you can click on the colored legends to turn them on and off and see a manufacturer's lot data in isolation.

Lot Size Distribution

Doses Shipped	Pfizer	Moderna	Janssen
Doses Shipped: Under 10,000	Pfizer: 1	Moderna: 5	Janssen: 2
Doses Shipped: 10,000-50,000	Pfizer: 3	Moderna: 10	Janssen: 1
Doses Shipped: 50,000-100,000	Pfizer: 1	Moderna: 5	Janssen: 4
Doses Shipped: 100,000-500,000	Pfizer: 6	Moderna: 32	Janssen: 13
Doses Shipped: 500,000-1,000,000	Pfizer: 19	Moderna: 84	Janssen: 14
Doses Shipped: 1,000,000-11,000,000	Pfizer: 154	Moderna: 14	Janssen: 14

All Serious Adverse Events
Deaths
Anaphylaxis
Severe Allergic Reaction
Myocarditis

source: OpenVAERS.com

* The scatterplots for this page were inspired by the work of Craig Paardekooper at https://howbadismybatch.com/ who analyzed the first incomplete batch of vaccine lot information in July 2022.

Do you want to look up a lot?

Search the Vaccine Lots