What is VAERS? A look at federal data tracking adverse reactions to coronavirus vaccines

Texas Coronavirus Vaccine

 AUSTIN (KXAN) — For decades, researchers and public health officials have relied on a set of federal data to track adverse reactions to vaccines and any potential patterns that might warrant further investigation.

As more and more people submit reports to the Centers for Disease Control and Prevention’s Vaccine Adverse Event Reporting System, or VAERS, on the coronavirus vaccine, there’s concern the data could be used to fuel misinformation.

VAERS is an open-access system that relies, in part, on reports from medical professionals and vaccine providers. Anyone can self report adverse events or reactions to a vaccine, as well. Then, the reports are publicly accessible on the CDC’s website.

The VAERS system includes several disclaimers about the data, including one that reads, “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.”

Still, social media users have pointed to VAERS data to bolster claims that thousands of deaths have been attributed to the COVID-19 vaccine. One viral post claimed a “6,000% Increase in Reported Vaccine Deaths” this year. KXAN investigators have received several questions about the VAERS data in recent weeks.

“Self-reports are always a type of surveillance that requires additional layers of scrutiny,” said Marilyn Felkner, a clinical assistant professor in the Public Health Program at the University of Texas at Austin. “Worst-case scenario, there are people who want to fake data.”

Felkner spent years doing public health surveillance for the Texas Department of State Health Services, tracking everything from foodborne illnesses to infectious diseases. She said more often than not, people simply confuse causation with coincidence.

For example, she explained a certain number of people will get a headache on any given day.

“If you get that headache the day after your vaccination, then you are likely to be more attuned to that,” she said.

Still, she noted that doesn’t mean people should avoid reporting any potential reactions. In fact, she said it was vital information for public health officials.

Felkner said the experts will begin looking for patterns in the reports and use “sophisticated algorithms” to determine if the adverse event could actually have been caused by a vaccine or might have another cause.

“Is it rising above that level, beyond coincidence?” she said.

Investigators will connect with the person reporting the adverse event, she explained, as well as try to gather background health data to better understand the situation.

Felkner noted medical professionals will often encourage patients to report any type of side effects, no matter how minor, to help give public health officials a better idea of the scope of how a vaccine is affecting a population. She even said people experiencing no side effects should report that information to health officials, so the data doesn’t have a ‘negative bias.’

“It’s just like in a business, if something really bad happens, then you want to go complain about it,” she said. “Recognize that if you are looking at VAERS data — by its very name — it’s telling you it’s ‘adverse events reporting.’ So, that’s all you are seeing. You are not seeing the hundreds of thousands of people who have been successfully vaccinated.”

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