COVID and Vaccine Adverse Event Reporting: How VAERS veers off course

My positions related to the pandemic are a matter of public record in word and video, from perches humble and rarefied. I respected, from the start, the dangers of the virus, and also the dangers of indiscriminate lockdowns. I favored, and still do, a strategy of total harm minimization– because there always was more than one way for this pandemic to hurt us. I favored, and still do, risk-stratified policies, because rarely in public health does one size fit all. Our “protections” were too severe in some cases, doing more harm than good, and not nearly enough in others.
Black and white image of an early locomotive crashing into an old city building

I open this way merely to grease the skids of tolerance: I adhere to consistent principles, and follow the weight of evidence where it leads. To the best of my ability, whether it brings me praise or excoriations, I place epidemiology ahead of ideology.

On that basis, I am now, as I have been throughout my 30-year career in medicine and public health, a staunch proponent of vaccines. Of course vaccines can do harm- every action and inaction can- but generally, the net benefit is massive. COVID is clearly no exception.

However, several colleagues and correspondents have directed my attention to the use of data from VAERS – the Vaccine Adverse Event Reporting System – by general public and even health professionals, in social media to highlight the harms of COVID vaccination and make a case against it.

I have looked over many such arguments, and they are, in a word: wrong.

VAERS is being used as a bludgeon by people who, with all due respect, would not have made it through week one of Epidemiology 101. I know, because I both took the course on my way to my MPH degree, and because I taught it to Yale medical students for over a decade.

To honor that history of pedagogy, let’s begin with a pop quiz:

1)  True or False: anyone can report an adverse vaccine event through VAERS?

ANSWER: True. The portal is open to everyone.

2)  True or False: adverse vaccine events reported through VAERS must be plausibly associated with the vaccine?

ANSWER: False. Any adverse event at all can be reported through VAERS, no matter how unlikely to be related to vaccination.

3)  True or False: an adverse event reported through VAERS must be verified to be due to the vaccine before being added to the data sets?

ANSWER: False. All adverse events reported are added to the data sets.

4)  True or False: health care professionals are required to report adverse events in the period following vaccination to VAERS, even if they don’t think the event is vaccine related?

ANSWER: True. While VAERS reporting is optional for the general public, it is mandated for health professionals. A wide array of adverse events occurring in the days and weeks following a vaccine, and death from any cause occurring in an extended period after a vaccine, are included. Further, the VAERS site states the following: “Healthcare providers are strongly encouraged to report: Any adverse event that occurs after the administration of a vaccine licensed in the United States, whether or not it is clear that a vaccine caused the adverse event.”

5)  True or False: The FDA and CDC encourage the public to report adverse events through VAERS, even if unlikely to be related to vaccination?

ANSWER: True. The VAERS site states: “Patients, parents, caregivers and healthcare providers (HCP) are encouraged to report adverse events after vaccination to VAERS even if it is not clear that the vaccine caused the adverse event.”

OK, that will do.

Considering the above, it is certainly possible that relatively minor adverse effects- a sore arm, a runny nose- might go under-reported. While the public is encouraged to report to VAERS, only health professionals are required to do so. Accordingly, adverse outcomes that require medical attention will be reported far more consistently than those that don’t. Let’s agree- vaccine proponents and opponents alike- that VAERS could, conceivably, under-report minor adverse events related to vaccination.

But what about major adverse events, including any and all outcomes that result in a visit to a health professional- and of course including all that result in hospitalization or death? These, inevitably, will be massively over-reported during a national vaccination campaign.

Why? First, because as noted, reporting by health professionals is mandated by law. And, specifically, adverse events, including death, in a fairly open interval following vaccination must be reported, even if not thought to be due to the vaccine.

Second, in any national vaccination campaign, with millions or tens of millions or even hundreds of millions being vaccinated- bad things will inevitably happen to many of us. Why? Because, sadly, bad things happen to some percentage of us, vaccine or no vaccine, every day, week, month, and year.

As an example: each year in the United States, pandemic or no, just a bit under 1% of the population dies. This may be tragic in many individual cases, of course, but overall it merely represents the “circle of life:” we are born we live, we grow old, and we die- and then another generation gets its chance. Nearly 1% of the US population is roughly 3 million people, which translates to 250,000 deaths each month, or over 8300 deaths every day.

Simply superimpose that normal, inevitable, annual death rate on a population-wide vaccination campaign affecting millions, and crude logic will tell you that the overlap will be vast.

Even if a vaccine actually caused not a single death, VAERS would be loaded up with reports of death that occurred following vaccination, from a variety of causes. VAERS is designed to be inclusive, not exclusive; to be sensitive, not specific. VAERS is designed to welcome false positives, to avoid the dangers of false negatives. VAERS is highly prone to mix together actual “cause and effect” with “true, true, and entirely unrelated.” These are, simply, facts of the system, there by design.

Yes, death from a traumatic car crash or fall in the week following a COVID vaccine could be reported via VAERS. Death by shark attack while surfing two weeks after a COVID vaccine…could be reported via VAERS. Death from lightning strike a month after a COVID vaccine…well, you get the idea.

Now, let’s turn our collective attention to a simple thought experiment to evince the dangers of VAERS data in the wrong, ideological hands.

Imagine in a given period, let’s say one month, that a million people receive a COVID vaccine (for our purposes here, it doesn’t matter which vaccine- we will assume comparable potential harms from them all). Let’s also image that during that same period, the same population experiences one thousand COVID infections. The COVID infection rate in this population is much lower than the vaccination rate for any of several reasons: the pandemic has mostly run its course in this population; and/or many people are immune due largely to vaccination, and partly to prior infection. These relative rates of vaccination versus infection are more or less realistic for many parts of the United States over recent weeks.

Let’s imagine, further, that the infection is 100 times more likely to cause harm than the vaccine (this is a figure that likely understates the actual differential by quite a lot), and that the infection harms one out of ten people.

So, out of 1000 people who got infected by SARS-CoV-2 in the past month, 100 would be “harmed” by the virus (1 out of 10). Out of the 1,000,000 vaccinated, 1000 would be “harmed” (100 times less risk than the virus, or one out of a thousand). For the sake of keeping this thought experiment simple, let’s just assume that the “harms” are comparable if not identical: whether minor, or severe, they are distributed comparably in the two groups. (Again, this is likely unfair to vaccination, but it works here).

A simplistic interpretation of the numbers above might be: “COVID vaccine harms ten times as many people as COVID infection!” This is just the sort of warning currently reverberating through social media and pop culture.

But this is not merely wrong, it is egregiously wrong.

You don’t make it through week 1 of Epidemiology 101 without learning to ask “what is the denominator?” So, what are the denominators?

For complications among the vaccinated, the denominator is all of those vaccinated, or one million. The total “harms” of 1000 out of 1,000,000 people translate to one person harmed for every 1,000 vaccinated.

In contrast, the 100 “harms” out of the 1,000 infected translates to one out of every 10. This makes the virus 100 times more dangerous than the vaccine. This is no surprise, since we started our thought experiment by “supposing” that the infection was 100-times more likely to do harm than the vaccine. So, that’s not the “aha!” moment here. The “aha” moment is that even if the vaccine causes 1000 harms in a population while COVID infection causes “only” 100, the infection may still be much, much more dangerous. And, in fact, it clearly is. (At the risk of stating the obvious: the lower rate of infection is because the vaccines work to prevent infection.)

Nowhere in the world have clinicians or health systems reported resource shortages due to a deluge of COVID vaccine complications. But clinicians and health systems all around the world have reported exactly that from SARS-CoV-2 infections. Nor need I take anyone’s word for this- I volunteered in the Bronx during the early surge in New York City, and I saw the hospital overwhelm for myself. The virus, while by no means equally dangerous to all of us, is monumentally more dangerous than vaccination.

Note that if the vaccine were only 50, 30, 20, or 10 times safer than infection, the “total harms” numbers would make the vaccine look even worse. And if the vaccine were a thousand times less likely to do harm than the infection- a very plausible differential- the total number of harms would nonetheless be the same. If the infection harmed 1 in 10 out of a thousand, that would be 100 harmed. If vaccination harmed 1 in 10,000 out of a million, that would also be 100 harmed.

These fundamental principles of epidemiology are widely applicable, of course, and not limited to infectious diseases, pandemics, and vaccination. In a given year in the United States, as many as 100 people may die while surfing. Each year in the U.S., well over 7,000 mostly elderly people die from falls while showering. If this persuades you that showering is 70 times more dangerous than surfing, I would very much like to sell you a bridge in Brooklyn; I’m sure Eric Adams won’t mind. The explanation, of course, is that vastly greater numbers of us are exposed to showers than surf boards. For any given one of us, surfing is, obviously, more dangerous than showering- no matter how good you may be at either.

By related math, comparable logic, and the inalienable principles of basic epidemiology- COVID vaccination is massively safer than COVID infection.

Does that mean vaccination is perfectly safe?

Of course not. Nothing in medicine, and virtually nothing in life is. In fact, one might argue that “primum non nocere” (first, do no harm) is not the right pledge for health professionals to take, because even when the right procedure is done for all the right reasons, it will occasionally result in harm. If, for instance, putting in intra-aortic balloon pumps is the best, or even only way to save lives in acute cardiogenic shock, but in 1 out of 100 on average there is a severe complication of this invasive procedure, the net benefit remains decisive: 99 out of 100 lives saved. The tragedy for the 1 out of 100 is no less because of good intentions, but the simple reality is that without a bold intervention, all 100 would have died. I have long thought “never do intentional harm and do as much net good as you possibly can” would be a better pledge for health professionals, but it admittedly lacks in both elegance and brevity.

Does that mean COVID vaccination is the obviously right tactic in everyone?

No, not necessarily. There is debate among knowledgeable, highly trained professionals regarding the risk/benefit ratio of COVID vaccination among healthy children, in whom the risks of COVID infection have been very, very low. I consider this debate entirely legitimate, particularly with evidence that the mRNA vaccines (Pfizer and Moderna) can cause heart inflammation in young people, males at least.

However, this debate must remain current as new viral strains proliferate; there are worrisome reports that the Delta variant is more dangerous to children than its predecessors. Whatever the right answer, the guiding principle is clear: the goal in public health efforts is to minimize the ratio of potential risk to likely benefit. If that introduces the challenge and nuance of risk-stratified rather than one-size-fits-all policies, so be it. We are duty bound to deal with that.

To sum up, I am a vaccine proponent for COVID and in general because of epidemiology, not ideology. I favor those efforts that reliably confer decisive net benefit to public health. I do not choose based on zero risk, because no such intervention exists. There is some, non-zero risk, in every potential action, and every potential inaction, too. The best we can do is…the best we can do.

VAERS is an important and powerful tool; so, too, is a freight train. With the wrong hands on the wheel, whatever the good intentions, either can veer off the tracks. The result, of course, is a train wreck.

My advice to you is choose your train wisely. And when you hear the screeching wheels of that veer, get out of the way.


This article was first published on LinkedIn.

Dr. David L. Katz is a board-certified specialist in Preventive Medicine/Public Health

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