Posts Misinterpret Pfizer COVID-19 Vaccine Safety Monitoring Document


SciCheck Digest

A Pfizer document recently released by the Food and Drug Administration describes adverse events reported following vaccination and attests to the continued safety of the company’s COVID-19 vaccine. A popular video and other online posts, however, incorrectly imply that the vaccine caused the events. Many posts also wrongly assume that a long list of health issues Pfizer is monitoring for occurred and were due to vaccination.

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After more than 1 billion doses administered worldwide — including more than 325 million in the U.S. — and more than a year of safety monitoring, the Pfizer/BioNTech COVID-19 vaccine is considered to be very safe. 

Many people experience temporary symptoms, such as fever, headache or pain at the site of injection. But those aren’t dangerous and are signs that the vaccine is working and the body is beginning to mount a protective immune response. More serious side effects can occur, but are rare.

The vaccine was first granted an emergency use authorization by the FDA in December 2020, based on a large phase 3 randomized controlled trial and other studies. In August 2021, it received full approval, after review of the manufacturing process and ongoing trial results and safety monitoring.

A flurry of articles and videos online are now misinterpreting a Pfizer document released by the FDA as part of a Freedom of Information Act request. The posts incorrectly claim that it shows the vaccine is unsafe and is evidence that this was hidden from the public.

“One year ago, these were side effects that Pfizer knew about,” conservative commentator Liz Wheeler says in an Instagram post, before highlighting a long list of so-called adverse events of special interest in the document’s appendix. 

“Look at how many side effects, adverse events, were recorded before the end of February of last year,” she said. “It’s shocking. It essentially admits that … this vaccine can cause you to miscarry your baby, this can cause you to die in any number of truly horrific ways.”

press release from Children’s Health Defense, Robert F. Kennedy Jr.’s anti-vaccination organization, similarly highlights the appendix and calls the document a “bombshell” that “should put an immediate end to the Pfizer COVID vaccines.”

John Campbell, a nurse educator in the U.K., whom we’ve written about before, also discussed the document in a popular YouTube video posted on March 9. In the video, which garnered more than 1.5 million views in just three days, he incorrectly implies that the vaccine caused the reported health problems. He also suggests Dr. Janet Woodcock, the acting FDA commissioner when the agency gave full approval to the Pfizer vaccine, was wrong to say that “millions of people have already safely received COVID-19 vaccines.”

“So how would you say it’s safe, when this document is indicating there’s been 1,223-associated deaths?” he asks.

He, too, focuses on the appendix’s list of adverse events of special interest. “The list is long, quite incredible really,” he says. “Why weren’t we made aware of these at the time? Because if we were aware of them at the time, we could have had an index of suspicion for them and kept an eye out for them.”

But, as we’ll explain, the appendix is just a list of conditions Pfizer was monitoring for, and the document supports the vaccine’s continued safety.

Misunderstanding ‘Adverse Events’ 

All of these posts misunderstand what is being reported in the Pfizer documentThe document is an analysis of adverse events, or health issues reported following vaccination, regardless of whether they were caused by the vaccine. Tracking of such events is useful for companies and regulators to identify possible safety signals, particularly of rare events that would not have been possible to detect in clinical trials.

This particular document covers the first three months of the vaccine’s rollout, and incorporates adverse event reports from across the globe. Through February 2021, it says, there were 42,086 reports of individuals reporting adverse events, including 1,223 deaths.

While on the surface those numbers could be alarming, it’s critical to understand that an adverse event is simply an event that has occurred after vaccination — it does not mean the vaccine necessarily caused the problem. And many of the events are likely to be purely coincidental.

“By definition, an adverse event is a temporal association,” Dr. Paul Beninger, a pharmacovigilance expert at the Tufts University School of Medicine, told us, referring to the timing of the event.

“Any health problem that happens after vaccination is considered an adverse event following immunization,” the Centers for Disease Control and Prevention explains. “An adverse event can be a true adverse reaction, also known as a side effect, that is related to the vaccine, or a coincidental event that happened following vaccination.”

Beninger said it was inaccurate for Campbell to say the reported deaths were “associated” with Pfizer’s vaccine. “They’re temporally associated, that’s the reason why they were reported. But the assessment’s not there to show that they were causally related,” he said. “You cannot call them vaccine-associated.”

Similarly, it’s not correct to call the adverse events “side effects,” as Wheeler did.

This confusion about adverse events is common and has been a frequent issue before with people distorting data from the ​​Vaccine Adverse Event Reporting System in the U.S. to argue that vaccines are unsafe, as we’ve written repeatedly before.

Because a variety of health problems, including death, occur in the population every day, it’s expected that many of these will be reported after vaccination, even if they have nothing to do with the vaccine. The challenge is to see whether the frequency of a particular event is elevated above the background rate, which could indicate a possible problem.

The released Pfizer document, it should be said, reviews the adverse events in groups according to organ type, noting each time that the evidence does not suggest a new safety signal. The analysis concludes that Pfizer’s post-marketing data “confirms a favorable benefit: risk balance” for its vaccine, and that the company will continue its monitoring “to assure patient safety.”

The Pfizer logo on the outside of a building in Belgium. Photo by Dieter Dewulf/DeFodi Images via Getty Images.

The first pages of the document, too, explicitly address many of the limitations of adverse event reporting to help properly interpret the data — limitations those posting alarming stories about the document appear to have ignored.

Pfizer’s analysis notes that the company’s safety database contains cases of adverse events “regardless of causality assessment” and says that numerous factors can influence whether an adverse event is reported, and that the “spontaneous reporting system should be used for signal detection.”

“An accumulation of adverse event reports (AERs) does not necessarily indicate that a particular AE was caused by the drug; rather, the event may be due to an underlying disease or some other factor(s) such as past medical history or concomitant medication,” it continues.

Far from proving that the Pfizer/BioNTech vaccine isn’t safe, the Pfizer document is evidence of the vaccine’s continued safety, Beninger said.

He also said that Woodcock was completely right to say that millions of COVID-19 vaccine doses had been administered safely. “Absolutely yes, categorically, no question,” he said.

Of Campbell, Beninger said, “His comments are very superficial and a lot of it is quite naive. The fact that all of those reports were there is proof of nothing, it all needs to be assessed.”

In the video, Campbell himself acknowledges that he struggled to read the document.

Misconstruing the Appendix

Many posts also err in their interpretation of the Pfizer document’s appendix, which is an alphabetical list of 1,291 adverse events of special interest. In her post, Wheeler even calls the appendix “the relevant part,” and Campbell argues the public should have been aware of the conditions so people could have “kept an eye out for them.”

But the appendix, Beninger said, was actually just a list of the things Pfizer was monitoring for — not a list of health problems that have been observed after vaccination or that had been shown to be due to vaccination.

One clue comes from its formatting, he said. “When events have actually happened, there is a breakdown,” he said. “They’re not presented in a massive alphabetical listing from A to Z.”


Some of the misleading online claims also center around how the Pfizer document was obtained and suggest there was a government cover-up, so we’ll provide some background on the topic.

As we’ve already established, there’s nothing to indicate that there was any identified safety issue, and therefore, there’s no evidence that regulators failed to share any important safety information with the public.

The document was released by the FDA in response to a Freedom of Information Act request from Public Health and Medical Professionals for Transparency. The group asked the FDA for all of its documents related to the Pfizer/BioNTech COVID-19 vaccine — or around 329,000 pages, plus other files — four days after the agency gave full approval to the vaccine.

The FDA did not oppose releasing the information, but denied the group’s request for expedited processing, leading PHMPT to sue the agency in federal court in September, as MedPage Today has explained

The FDA argued that the group’s request would require releasing 80,000 pages a month, which the agency said had never happened before with any FOIA request, and was difficult if not impossible with its current staffers, who would need to go through the documents line by line and redact exempted material. The FDA proposed releasing 500 pages a month instead, which it said was the standard rate. 

PHMPT, meanwhile, countered that that proposed rate would take nearly 55 years — and it was “difficult to imagine a greater need for transparency” than making the vaccine documents available.

On Jan. 6, a judge in North Texas recognized the “‘unduly burdensome’ challenges” of the FOIA, but sided with the plaintiff, concluding the request was of “paramount public importance.” He set the deadline for the first tranche of documents for Jan. 31, with another 55,000 pages to be released every month. At that pace, all of the information will be released by the end of the summer.

PHMPT then posted the documents on its website. Shortly thereafter, misleading or false claims began circulating online about the safety of the Pfizer/BioNTech vaccine using the documents, which our colleagues at Health Feedback have also addressed.

As MedPage Today has explained, the FDA has already released summaries of the data it has reviewed, and the FOIA documents “may not be material to an overall analysis of the vaccine’s safety and efficacy.” Zach Zalewski, a regulatory strategy consultant at Avalere Health, told the outlet, “There’s a risk of cherry picking and taking things out of context.”

Beninger, however, said the FDA had been “a bit tone deaf to what’s going on around them,” and said he thought that the agency should have been more attentive. “I just think you have to virtually bend over backwards to be transparent,” he said.

It’s worth noting that while Campbell calls the people who have joined PHMPT “prestigious” and “highly qualified,” the list is primarily notable for its inclusion of multiple individuals who have made dubious claims about COVID-19 or the vaccines. Among several others, the list of signatories includes Idaho pathologist Dr. Ryan Cole, who has baselessly said that the vaccines cause cancer, and Dr. Stella Immanuel, who has falsely promoted hydroxychloroquine as a COVID-19 “cure” and has previously claimed that some medicines are made of space alien DNA.

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’s 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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