Antivaccine activists use a government database (VAERS) on side effects to scare the public,

In response to: On 5 May, Fox News host Tucker Carlson delivered a 10-minute monologue casting doubt on the safety of COVID-19 vaccines on his show, Tucker Carlson Tonight. He announced that almost 4000 people had died after getting COVID-19 vaccines, and added that those data "comes from VAERS,"—the Vaccine Adverse Event Reporting System, a U.S. government program that collects reports of side effects possibly caused by vaccines.

It was a misleading statement. The reporting of a death to VAERS indicates nothing about what caused it, and the Centers for Disease Control and Prevention's (CDC's) subsequent investigations have found no indication that deaths were caused by COVID-19 vaccines, save in a small subset with an extremely rare clotting disorder linked to one vaccine. But the TV segment pulled VAERS, a 31-year-old early warning system widely relied on by scientists, even deeper into the culture wars over vaccination. After the broadcast, a new phalanx of antivaccine activists began plumbing VAERS for data to scare the public about vaccination, says Angelo Carusone, president of Media Matters for America, a left-leaning nonprofit that is monitoring anti–COVID-19 vaccine activity on social media. "We have been tracking these attacks since February and this one resonated in a different way after Tucker hit it," Carusone says.

It has been distressing to watch for researchers who use VAERS to detect real vaccine side effects—such as the very rare clotting disorder linked to the Johnson & Johnson (J&J) vaccine—and to rule out others, thus providing both safety and reassurance to the public. "I can't believe people are using this database now to try to form this antivaccination argument," says Eric Formeister, an ear surgeon at Johns Hopkins University.

Formeister and colleagues turned to VAERS, which is run by CDC and the Food and Drug Administration, after hearing anecdotal reports from patients of sudden hearing loss after COVID-19 vaccination. Their analysis of VAERS data concluded hearing loss was no more frequent, and possibly less frequent, among vaccine recipients than in the population as a whole, as they published in JAMA Otolaryngology last week. CDC is now using VAERS data to probe whether COVID-19 vaccines might rarely be causing heart inflammation in children; it has not yet reached a conclusion.

One of VAERS's strengths—its openness—is also a potential weakness in the politicized COVID-19 era. Anyone who receives a vaccine authorized in the United States can report an adverse event to VAERS, as can doctors, family members, and others. That openness ensures VAERS receives plentiful reports—228,000 for COVID-19 vaccines alone since December 2020, more than four times the number received in all of last year for all vaccines.
Some worry this might make it easy to post false reports. But CDC removes data that are clearly fake, such as a recent report purportedly filed by Brazilian President Jair Bolsonaro about an adverse event in a beach volleyball superstar. And deliberate, false reporting to VAERS, which is a federal criminal offense, appears to be rare. "We don't have evidence that there is widespread fraud or gaming of the system," says Tom Shimabukuro, deputy director of CDC's Immunization Safety Office, which oversees VAERS. "We have to balance keeping VAERS an open system and getting as much information as we can on vaccine safety against potential data quality problems."

But even honest reports can be used to spook the public. The reports themselves are not vetted, and, as CDC states in a prominent disclaimer, they "may include incomplete, inaccurate, coincidental and unverified information."