The Vaccine Adverse Event Reporting System, or VAERS, database has been fodder for anti-vaccine activists since before the COVID-19 pandemic. The reporting system, which is jointly run by the Centers for Disease Control and Prevention and the Food and Drug Administration, is the nation’s early warning system to detect possible safety problems with vaccines after they are rolled out to the public. 

Vaccines are always rigorously tested before widespread use, but the clinical trials can only be so large and cannot rule out rare safety concerns. For this reason, VAERS is used, in conjunction with a variety of other vaccine safety monitoring systems, to quickly identify potential problems, which are then investigated.

Importantly, anyone can submit a report of a symptom that occurred following vaccination. The reports are not vetted for accuracy, nor do they mean that the symptom was necessarily caused by the vaccine. In many cases, the symptom is purely coincidental.

These basic facts about VAERS, which are prominently advertised in a disclaimer that users must agree to before accessing the database, haven’t stopped people from misinterpreting the system’s data and using it to lend inaccurate or unsupported claims about vaccines a veneer of scientific and governmental legitimacy. And with the arrival of the three FDA-approved or -authorized COVID-19 vaccines, claims using VAERS have gone into overdrive.

Television personalitiesanti-vaccine websites and social media posts have all cited figures in VAERS or similar reporting systems abroad to falsely suggest that the COVID-19 vaccines aren’t safe, as we have written. The vaccines are remarkably safe — typically triggering only temporary and expected side effects that are signs that a person’s body is mounting the proper immune response — and are associated with only a few, very rare serious adverse events.

In fact, VAERS has successfully helped to identify those rare but very real problems, which include heart inflammation for the Pfizer/BioNTech and Moderna mRNA vaccines, and a blood clotting disorder coupled with low platelets for the Johnson & Johnson vaccine — exactly as designed.

The latest VAERS-inspired claim attempts to cast doubt about the safety of the COVID-19 vaccines by highlighting the high number of reports to the safety system compared with past vaccines.

“How can it be that adverse event reports input to VAERS are greater, since the COVID vaccines were rolled out, than all cumulative adverse event reports to VAERS for the prior thirty years?” a post from Children’s Health Defense, Robert F. Kennedy Jr.’s anti-vaccination organization, suggestively asks. “Death reports for 2021 are also greater than cumulative deaths reported to VAERS over the preceding 30 years. Why has no public health official explained this?”

A December post from Health Impact News, a website known for spreading misinformation about vaccines, makes the same insinuating argument. “There are now 927,740 cases reported to VAERS following COVID-19 shots for the past 11 months, out of the total of 1,782,453 cases in the entire VAERS database filed for the past 30+ years,” the post reads. “That means that 52% off ALL vaccine adverse reaction cases in VAERS for the past 30+ years have been reported in the last 11 months following the COVID-19 shots.”

The figures, which reflected the totals in the database as of a few weeks ago, are accurate, although they’re cherry-picked to be as high as possible, as they include reports from abroad; more than a quarter of the COVID-19 reports are foreign.

More important, experts say there are plausible reasons for why the COVID-19 total is so high — and because of VAERS’ design, comparisons between vaccines are invalid. The statistics are not proof that the COVID-19 vaccines are dangerous or significantly less safe than previous vaccines.

COVID-19 Vaccine Reporting Requirements

The two posts are similar to a claim that USA Today fact-checked back in June, when the conservative website enVolve falsely said the “death toll” from the COVID-19 vaccines was more than 20 times greater than all past vaccines combined.

They are also reminiscent of another baseless claim we addressed in February — again predicated on VAERS data — that a person is 300 to 900 times more likely to die “after getting the #Covid vaccine than the flu vaccine.”

As we explained then, the huge number of VAERS reports following COVID-19 vaccination and relative paucity for other vaccines is likely mostly due to a reporting bias. For one, because the COVID-19 vaccines are or were at first authorized under an emergency use authorization, there are much broader reporting requirements for health care providers.

For the COVID-19 vaccines, health care providers are required by law to report any vaccine administration error; any serious adverse event following vaccination, regardless of the suspected cause; any case of Multisystem Inflammatory Syndrome; and any COVID-19 case that results in hospitalization or death.

In contrast, with all other vaccines, providers are only required to report select adverse events, including the so-called reportable events for each vaccine that occur within a certain time period after vaccination, such as an allergic anaphylactic reaction.

Increased Vaccine Awareness

Then, there’s the fact that the COVID-19 vaccines have been under intense scrutiny.

“The pandemic has raised awareness of VAERs, the virus, and potential vaccine-induced adverse events to an all-time high,” Jeffrey S. Morris, a biostatistician at the University of Pennsylvania told us in an email interview for this story.

“The extreme awareness, attention and concern about vaccine safety induced by the conditions of the pandemic in the past year could conceivably lead to much higher reporting than past years for other vaccines,” he said. “Thus, we can’t rule out that the greater number or events in VAERs may be a result of increased reporting and not a function of a more dangerous vaccine.”

Part of this is standard for any new vaccine. “When a new vaccine comes out, there’s a lot of attention paid to whatever the profile is of those adverse events, so that the routine vaccinators understand what to expect as time goes on,” Dr. Paul Beninger, a pharmacovigilance expert at the Tufts University School of Medicine, told us.

He said that there’s even a phenomenon known as the Weber effect, in which heightened awareness of a new vaccine leads to a spike in reports to safety systems such as VAERS, before rapidly declining. Reports to VAERS for one of the HPV vaccines, for example, shot up to triple the rate for all other vaccines combined between June 2006 and December 2008, likely related to media coverage of the new vaccine.

But given that press coverage of COVID-19 and the COVID-19 vaccines is unprecedented in modern history — and that hundreds of millions of doses have been rolled out in less than a year, when most of the vaccines have been authorized for emergency use rather than a full approval — it’s reasonable to expect that any Weber effect would be even greater for the COVID-19 vaccines than for a typical vaccine.

Hundreds of Millions of Doses

Indeed, part of the reason for the large number of reports is simply that the COVID-19 vaccines, which may involve as many as three doses, have been given to many millions of people. As of Dec. 21, more than 497 million doses of COVID-19 vaccine have been administered in the U.S., according to the CDC. That total is still likely well below the total number of all vaccine doses given since 1990, when VAERS began, but it’s a large number of shots given in a very short period of time, when awareness of the vaccines has arguably never been higher.

Beninger also said that with the COVID-19 vaccines, the people administering the vaccines have changed. In the past, the most experienced vaccinators have often been pediatricians. But he suspects a shift to more inexperienced vaccinators has also contributed to increased reporting in VAERS.

“Many people who are giving the vaccines are really very new to the whole vaccine paradigm,” he said. “They’re inexperienced in giving them and they’re inexperienced in assessing them.”

“They don’t have the experience to say, ‘I don’t think this is related, so I’m not going to report,’” he added. “They’re encouraged to report. There’s some inflation.”

Different Populations

As we pointed out back in February when we evaluated the similar claim about COVID-19 and flu vaccines, another factor potentially leading to more reporting than normal in VAERS is the population receiving the vaccine.

While all adults and some children are now eligible to be vaccinated, the early emphasis on higher-risk individuals has meant far more of them are vaccinated. Dr. Paul A. Offit, a vaccine expert at the Children’s Hospital of Philadelphia and a member of the FDA’s vaccine advisory committee, told us then that because the vaccines protect against COVID-19 but were “not designed to prevent everything else that happens in life,” it’s expected that some number of people — especially the elderly — will die or have other complications, entirely coincidentally, after receiving a vaccine.

Echoing Beninger, Dr. Robert Legare Atmar, an infectious disease specialist at Baylor College of Medicine who also evaluates vaccines, told us then that during flu season, many of the everyday deaths of people in nursing homes, for example, might have been reported to VAERS this year if someone received a COVID-19 vaccine. In the past, however, a similar death during flu season would not be reported because it would not be thought to be related to the vaccine.

Vaccine Safety ‘Mania’

Morris, the University of Pennsylvania biostatistician, also suspects that social media and misinformation — including posts sharing this kind of misleading information — helped fuel reporting to VAERS after COVID-19 vaccination. He has spent a lot of time during the pandemic debunking bogus claims about vaccines, including distortions of government data, which he shares on Twitter and on his blog.

False but sensationalistic claims on social media, such as the vaccines magnetizing people or changing a person’s DNA, he said, “fed the mania about vaccine safety,” while so-called “vaccine safety alarmists” repeated anecdotal reports and analyzed VAERS data incorrectly to much the same effect.

“All of this frenzy, fed by social media in a way that has never been done with previous vaccine efforts, raised worry about vaccine safety, which certainly would have led more to report to VAERs, perhaps more fraudulent reports from people with an agenda,” he said, “but also from people who are simply more aware of VAERs and more mindful of potential vaccine effects, who normally would not have associated the side effect with vaccination.”

In that way, the posts’ creators themselves may have helped produce the very result that they are writing about — and are now using it to further undermine the vaccines.

We asked the Department of Health and Human Services to explain why VAERS reports are so much higher for the COVID-19 vaccines, and the CDC replied, identifying many of the reasons as the outside experts.

The three main reasons, the agency’s immunization safety office told us, were the different reporting requirements, the large number of people vaccinated in a short amount of time, and heightened public awareness.

“COVID-19 vaccination is one of the top national news stories daily and VAERS has also been a frequent topic in media,” the safety office told us.

The agency said that it “cannot always identify reports that are fraudulent,” but that it had observed a “huge increase” in hoax reports to VAERS. These reports are obviously false, list celebrities or state outrageous claims, and often do not include contact information for follow-up, the CDC said. The hoax reports, which are deleted, make up less than 1% of all VAERS reports following COVID-19 vaccination, the agency said.

Knowingly filing a false VAERS report is illegal and can result in fines or imprisonment.

The CDC emphasized that VAERS is just one part of a large network of vaccine safety monitoring systems. “It is important to note that VAERS is only one system among many that monitor the safety of US-licensed or authorized vaccines,” the agency said in an email (emphasis is the CDC’s). “Each system has different strengths and weaknesses.”

VAERS, for example, is useful as a method of identifying purported safety problems, which must then be followed up in the government’s active reporting systems or in population-level studies, Morris said. Those active systems include the CDC’s Vaccine Safety Datalink, which uses electronic health data from nine health care organizations in the U.S. to identify adverse events related to vaccination in near real time.

“[T]hese have affirmed many of the events with high reporting rates in VAERs have similar rates in vaccinated and matched unvaccinated cohorts,” he said, so they show “no evidence of association or causation by vaccines.”

Morris pointed to an Israeli study published in the New England Journal of Medicine that identified the increased risk of myocarditis, or heart inflammation, in recipients of the Pfizer/BioNTech vaccine, but also showed that the myocarditis risk for COVID-19 patients was higher — and found that many other serious adverse events thought to be potentially related to the vaccine were actually observed at similar rates in vaccinated and unvaccinated people.

VAERS alone, however, can’t be used to know the frequency of adverse events, as its website explains, or to make comparisons about the relative safety of different vaccines.

“That’s not the point of this database,” Beninger said of VAERS. “It’s not a comparative study.”

Morris also said he had analyzed Centers for Medicare & Medicaid Services data on the frequency of deaths among Medicare patients within two weeks of vaccination, and found that the rate in 2021 after the COVID-19 vaccines was “roughly equivalent” to the rate in 2018 to 2020 following the influenza vaccine. Both of these reflect a background rate of death.

As he explains in a blog post and Twitter thread, a purported whistleblower had tried to use the data to argue that the death rate is twice as high after COVID-19 vaccination compared with the influenza vaccine. But that person failed to account for the fact that most Americans received a two-dose mRNA vaccine.

As a result, far from proving the death claim, the data show the opposite — that there’s no sign the COVID-19 vaccines are any different from the flu vaccine — and what’s happening in VAERS is increased reporting rather than a sign that the vaccines are causing excess deaths.

If the CMS data is accurate, Morris told us, it provides “rock solid evidence” that a larger proportion of deaths that occur after vaccination were reported to VAERS in 2021 for the COVID-19 vaccines than in prior years with other vaccines.

Because no medical product is 100% safe, a very small number of people will be harmed by the COVID-19 vaccines, which is why it’s so critical to have a system such as VAERS and why it’s important to be transparent about the potential risks. But distorting and misusing VAERS figures to insinuate there are large safety concerns that have not been detected after administration of nearly half a billion doses in the U.S. is misleading.

Editor’s note: SciCheck’s COVID-19/Vaccination Project is made possible by a grant from the Robert Wood Johnson Foundation. The foundation has no control over our editorial decisions, and the views expressed in our articles do not necessarily reflect the views of the foundation. The goal of the project is to increase exposure to accurate information about COVID-19 and vaccines, while decreasing the impact of misinformation.

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