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Madeline Heim
By Madeline Heim March 1, 2022

No, vaccination does not cause COVID-19 to mutate faster

If Your Time is short

  • The COVID-19 virus tries to evade any kind of immunity to stay alive, not just immunity that comes from a vaccine, said Ajay Sethi, an associate professor at the University of Wisconsin-Madison. 

  • In addition, being vaccinated can reduce a person’s risk of becoming infected with the virus — and if they are infected, their course of illness will be shorter than a person who is not vaccinated, data show. 

  • That would curb virus mutation, not speed it up.

Wisconsin’s Republican-controlled Senate has advanced a bill that would count prior COVID-19 infection as immunity, a sure sign that the partisan fight over the state’s pandemic response will continue to churn along. 

The bill was passed Feb. 15, 2022 and is all but certain to be vetoed when it reaches Democratic Gov. Tony Evers’ desk. 

But the body’s discussion of the bill underscored the deep divide between Evers and Republican members of the Legislature about how to bring the pandemic to an end. 

That discussion also included misinformation about COVID-19 vaccination from Sen. Mary Felzkowski, R-Irma. 

"Over-vaccination causes faster mutation of the virus, which causes a super virus we may not have the ability to fight off," Felzkowski told her Senate colleagues during the floor session. 

She’s way off base. 

Let’s break it down. 

Vaccines don’t cause COVID to mutate faster 

Felzkowski’s office did not respond to a request for evidence to back up her claim. 

In any case, the claim is inaccurate, said Ajay Sethi, associate professor of population health sciences at the University of Wisconsin-Madison School of Medicine and Public Health. 

The virus will always try to mutate to guarantee its own survival and evade people’s immunity, Sethi said in an email — and it doesn’t care whether that immunity comes from a vaccine, from prior infection, or both. In other words, it’s not mutating faster because people are vaccinated.

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Politifact National rated a similar claim False last May, when a French virologist said  vaccination is creating the virus variants. 

In that fact-check, Dr. Sarah Fortune, chair of the immunology and infectious diseases department at Harvard T.H. Chan School of Public Health, offered the same conclusion that Sethi did. 

"Either people are going to get sick and get COVID-19, and the virus tries to escape that immune selection, or people can be vaccinated and the virus is going to try to escape that immune selection," Fortune said. "Avoiding vaccination is not going to limit the evolution of the virus." 

In fact, vaccinations play a role in slowing mutations of the virus. 

Each new infection gives the virus another chance to mutate. While it’s possible for people who are vaccinated to become infected with COVID-19, research shows getting the shot makes that less likely to happen. Data from the Wisconsin Department of Health Services, for example, show that in December 2021, unvaccinated people were testing positive for the virus at a rate that was three times higher than vaccinated people. 

Vaccinated people who do contract the virus also have a shorter course of illness than unvaccinated people, Sethi said, reducing the time and thus the opportunity for it to spread further, which gives it a greater chance to mutate.

As for Felzkowski’s claim about a "super virus," it is possible that a variant that can evade all forms of immunity could develop. But as explained above, that wouldn’t be caused by vaccinations — it would be caused by unfettered spread of the virus through the population. 

"If the next Variant of Concern circumvents immunity from vaccines, immunity from past infection, and monoclonal antibody treatments, it is because society allowed the virus to continue to spread, evolve and mutate into new variants," Sethi said. 

Our ruling

Felzkowski said "over-vaccination" causes the COVID-19 virus to mutate faster, which could produce a virus that humans may not be able to fight off. 

But state and national experts agree that the virus is seeking to evade any form of immunity to stay alive, not just immunity from vaccines. In reality, vaccines can play a role in slowing mutation of the virus because vaccinated people are less likely to become infected and tend to recover quicker. 

We rate her claim False. 


Our Sources

Associated Press, "Wisconsin Senate approves protections for unvaccinated," Feb. 15, 2022

Email exchange, Ajay Sethi, associate professor of population health sciences at the University of Wisconsin-Madison School of Medicine and Public Health 

Politifact, "COVID-19 vaccines do not create the virus' variants," May 28, 2021

Associated Press, "No evidence COVID-19 vaccines create new virus variants," May 26, 2021

Wisconsin Department of Health Services, COVID-19: Illness after vaccination, accessed Feb. 23, 2022

USA TODAY, "Fact check: Vaccines protect against contracting, spreading COVID-19," Nov. 17, 2021

MedRxiv, Viral dynamics of SARS-CoV-2 variants in vaccinated and unvaccinated individuals, Aug. 25, 2021


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No, vaccination does not cause COVID-19 to mutate faster

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