The So-Called Pfizer Gotcha is Exactly What You Would Expect
Yes, it turns out to be reckless antivax fearmongering disinformation.
By Ryan McGreal
Posted March 19, 2022 in Blog (Last Updated March 19, 2022)
If you follow the antivax movement at all, you’ve probably noticed a recent commotion about a collection of Pfizer documents released by the FDA as part of a freedom of information request, and you may be wondering what all the fuss is about.
Naturally, the antivaxxers are presenting it as validation for all their fearmongering about the Pfizer vaccine’s safety. Given the antivax movement’s reckless disregard of the most basic norms of evidence and reasoning, you are right to be skeptical.
Their ‘smoking gun’ is a nine-page list of adverse events that were reported following vaccinations. Understanding how clinical research actually works is crucial to understand how to interpret what this list means.
Vaccine manufacturers and public health regulators have a strong interest in knowing about any potential side effects of vaccines, so there are databases where people can submit reports of adverse events following vaccination.
For example, in Canada the Public Health agency maintains the Canadian Adverse Events Following Immunization (CAEFI) database, to which doctors, nurses and pharmacists can submit adverse event reports from their patients.
In the USA, the CDC maintains the Vaccine Adverse Event Reporting System (VAERS), which serves a similar role. (One difference is that anyone can submit a report, not just health care professionals.)
Likewise, the World Health Organization also maintains an Adverse Events Following Immunization (AEFI) database, and so on.
The important thing is that these are collections of raw, self-reported anecdotes. Anyone can submit an adverse event report to VAERS after receiving a vaccine. Just because an incident happens after a vaccination, that doesn’t mean the incident was caused by the vaccine.
Think of it this way: 11 billion COVID vaccines have been administered worldwide, and a little over 5 billion people have received at least one dose. How many adverse incidents would you expect to happen among a group of 5 billion people over the course of a month? Answer: a lot.
So when you vaccinate 5 billion people, there are going to be events that happen soon after vaccination - everything from fevers to heart attacks and strokes - that have nothing to do with the vaccine and would have happened anyway.
The difference between an adverse event following a vaccine and an event caused by the vaccine is if the event is more frequent in a population that was recently vaccinated than in a control group that was not recently vaccinated.
When adverse events are reported to CAEFI or VAERS, researchers look for repeated events that might indicate a pattern. From there, they do further research to determine whether these events are happening at a higher frequency following vaccination.
This is how, for example, the risk of a rare vaccine-induced blood clot (VITT) was discovered following AstraZeneca vaccinations, which occurs in around 1 in 50,000 vaccines administered to people under age 50.
(And of course, the risk of blood clots from COVID infection itself is orders of magnitude higher than the risk from the vaccine.)
So, back to that nine-page list of adverse events following the Pfizer vaccine. It is an unvetted list of anecdotal adverse event reports that were submitted to Pfizer as part of its safety review process, not a controlled study of events caused by vaccines.
But of course, the antivaxxers are ignoring this crucial distinction and presenting it as if it was a list of events caused by vaccines.
Reuters has a fact-check on the antivax fearmongering.
But there is more to this story.
You may have heard of the placebo effect, which is the perception of benefit after receiving something you think will benefit you. Sometimes, people feel better if they think they received a treatment, even if they didn’t actually receive it.
In a controlled study of a treatment, a test group receives the treatment and a demographically matched control group receives a pretend treatment that doesn’t have any medical effect.
To account for the placebo effect, a treatment is considered effective only if the benefit observed in the test group is significantly higher than the ‘benefit’ observed in the control group that received the placebo.
But the placebo effect has an opposite: the “nocebo effect”, which is a perception of harm after receiving something that you think will harm you, even when it doesn’t have any negative effect.
Because of all the media attention given to COVID vaccines and their side effects, vaccine researchers have observed a pronounced nocebo effect among control groups that received a pretend vaccine during vaccine trials.
A meta-analysis of several studies that was recently published in JAMA Network Open found that most of the adverse events (AEs) reported after COVID vaccines were actually nocebo effects.
The paper concludes: “AEs in placebo arms (“nocebo responses”) accounted for 76% of systemic AEs after the first COVID-19 vaccine dose and 52% after the second dose.”
This is why it is so important to study adverse event reports before assuming an event was caused by a vaccine.
If misinformation and faulty reasoning leads people to think vaccines are more risky than they really are, the choice to refuse the vaccine can lead to COVID and a high risk of serious illness and death - real dangers that antivaxxers routinely downplay or deny altogether.