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One year into COVID shots, misleading VAERS claims persist

January 12, 2022 GMT

CLAIM: There have been one million COVID-19 vaccine adverse events reported to the federal database VAERS.

AP’S ASSESSMENT: Missing context. VAERS is an early warning system through which the U.S. Centers for Disease Control and Prevention and the Food and Drug Administration keep tabs on signals of possible side effects from vaccines. However, the passive reporting system, which relies on unverified reports submitted by the general public, is not an official database for proving that the vaccine caused the adverse events reported.

THE FACTS: In the year since the COVID-19 vaccines began rolling out in late 2020, more than 500 million doses have been administered in the U.S.

But it’s a different number that has been the persistent focus of some vaccine threads online: the total number of reports submitted to the Vaccine Adverse Event Reporting System, or VAERS.

Social media posts in recent days — including a tweet from Wisconsin Sen. Ron Johnson — have relayed the purported milestone of “1 million adverse events” being reported to VAERS in relation to the COVID-19 vaccines.

The posts leave out the important context that such reports are not verified. And that number also includes more than 300,000 reports from abroad, as well as those from the U.S.

As the AP has reported, VAERS allows anyone to submit a report on any possible reaction after the vaccine, and has clear disclaimers that reports may “contain information that is incomplete, inaccurate, coincidental, or unverifiable.”

The system is passive, meaning people self-report by submitting their personal information. Health care providers and manufacturers are also required to submit adverse responses reported after vaccines, even if they don’t know whether the vaccine caused them.

While the system has many limitations to how its information can be used, VAERS is considered a first step in detecting issues and concerns that can then be investigated, experts say.

No vaccine is 100% safe or effective, and rare adverse events are possible. VAERS identifies unusual patterns that can help alert medical professionals to probe further.

“They are to generate a question, not to answer the question,” said Al Ozonoff, associate professor of pediatrics at Harvard Medical School.

For instance, in the case of the COVID-19 vaccines, health care officials were able to note early reports of anaphylaxis with the Pfizer-BioNTech vaccine and rare blood clots forming after the Johnson & Johnson vaccine.

Johnson not only cited VAERS data in his Twitter remarks but data from the FDA’s Adverse Event Reporting System as well, in an attempt to compare reports about the vaccines to reports about other drugs. But similar to VAERS, the FDA’s system comes with a disclaimer that while the system keeps reports of adverse events related to products, that does not mean the products are responsible for the adverse outcome.

Asked about Johnson’s tweet, Alexa Henning, a spokeswoman for Johnson, said in an email that the senator has said multiple times that “VAERS does not prove causation but should be used as an early warning system.” She added that he “certainly believes that the agencies should be concerned about what VAERS is showing related to COVID-19 vaccines and they should fully investigate.”

Experts say the total number of unverified reports to VAERS, which can include reports of both mundane and serious issues, doesn’t say much.

“This number provides very little information upon which to base conclusions about the safety of the vaccine,” said Dr. Caleb Alexander, a professor of epidemiology and medicine at Johns Hopkins Bloomberg School of Public Health. “We actually know from much better sources of data that the vaccines are incredibly safe.”

Various factors could also be helping to drive the number of reports to VAERS about COVID-19 vaccines. The “enormous number of people who have been vaccinated” as well as daily attention on the vaccines and on vaccine safety, for example, could contribute to a high number of reports, Ozonoff said.

Despite the misleading posts surrounding VAERS, Richard Carpiano, a professor of public policy at the University of California, Riverside, and expert on anti-vaccine groups, said the system should continue to remain public.

“It’s very much damned if you do and damned if you don’t,” he said. “People want transparency so they’ve got transparency. We have a fantastic vaccine surveillance system for picking up signals. VAERS is only one of those.”


This is part of AP’s effort to address widely shared misinformation, including work with outside companies and organizations to add factual context to misleading content that is circulating online. Learn more about fact-checking at AP.