Michael Hunter, MD on Medika Life

COVID Vaccine Versus Infection: Which Confers More Immunity?

COVID VACCINATION OFFERS MORE PROTECTION than being infected by the virus. That’s the conclusion of a new study that seems to confirm what many believe.

Here’s my initial response: It is no surprise that vaccination is better than infection. The vaccine is reasonably well-tolerated, while the infection can make me quite ill or even take my life.

But not so fast; that is different from what the research says. The study’s most provocative finding is that vaccination appeared to be more effective than infection, even among those who have recovered from a COVID-19 infection. I am surprised by this observation.

“The important thing is not to stop questioning. Curiosity has its reason for existence. One cannot help but be in awe when he contemplates the mysteries of eternity, life, and the marvelous structure of reality. It is enough if one merely tries to comprehend a little of this mystery daily. ― Albert Einstein

COVID vaccination in the vaccinated and infected

When COVID-19 hit the world scene, it was remarkably dangerous because non of our immune systems had ever faced it.

I raced to teach my immune system; I remember how excited all of my radiation oncology staff were when our vaccination turn came. We all preferred this immune system education over exposure to COVID-19 and its unknown hazards.

Photo by Daniel Schludi on Unsplash

But what about those who have already suffered a COVID-19 infection? Could the fact that a “real” infection exposes us to many more COVID-19 antigens (than does a vaccine) translate into more protection? You may be surprised that until now, we did not have an answer.

Indiana (USA) researchers recently reported thought-provoking results in their study “SARS-CoV-2 Infection, Hospitalization, and Death in Vaccinated and Infected Individuals by Age Groups in Indiana, 2021–2022.

The scientists identified COVID-infected individuals who had not been vaccinated. They also analyzed people who had been infected but had not suffered from an infection.

The researchers then matched individuals between the groups: For each vaccinated individual, they simultaneously located one who had been infected. They matched sex, age, race, zip code, and pre-existing conditions.

Thirty days after a vaccine or infection event, the analysis began. The investigators believed that exposure-induced immunity should have been established by that time. Here are the results:

The vaccinated individuals were approximately twice as likely to become infected in the next six months than the previously infected people.

But here’s an important supplement: The vaccinated folks did better regarding other outcomes, including emergency department encounters, hospitalizations, and death.

COVID-19 infection versus vaccination — My take

It seems obvious that if you had to choose one or the other, COVID-19 infection versus vaccination, you’d opt for the jab. But nothing is ever simple.

Are those of us who chose a vaccine the same as those who did not? While the study authors tried to control for confounding factors, this is a quite imperfect science. Are the vaccinated more healthy? I suspect so. Moreover, the vaccinated amongst us seem to be more careful about masking and cleaning surfaces.

“There are three kinds of lies: lies, damned lies, and statistics.” — Unknown author.

Yale’s F. Perry Wilson, MD, points out a problem with the study’s methods. I will let him explain the issue:

“The researchers censored matched pairs when an infected participant received a vaccination, or a vaccine recipient became infected. At first glance, this seems logical (as we no longer see the “benefit” of prior infection alone).

But censoring a matched pair when the vaccinated member of the pair gets COVID means that you can never observe things like death from COVID in that individual; all events must happen before infection. There is an argument that this is fair since the infected person in the pair, by design, had survived their COVID infection for at least 30 days. But I am concerned that this would bias the results to favor vaccination.”

Photo by Glen Carrie on Unsplash

While the study results are provocative, they are no longer relevant for many of us. I had a COVID-19 infection, and you probably did, too. Most of us don’t have to ask ourselves to choose between natural infection and vaccination. If you have been infected with COVID-19, how much value does a vaccine confer?

Thank you for joining me in this look at COVID vaccine versus infection — Which confers more immunity?


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Michael Hunter, MD
Michael Hunter, MD
I received an undergraduate degree from Harvard, a medical degree from Yale, and trained in radiation oncology at the University of Pennsylvania. I practice radiation oncology in the Seattle area.

Michael Hunter, MD

I received an undergraduate degree from Harvard, a medical degree from Yale, and trained in radiation oncology at the University of Pennsylvania. I practice radiation oncology in the Seattle area.

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