Fact check: Herd immunity would not fully stop the spread of coronavirus

Claim: Herd immunity, not social distancing, would stop COVID-19

Although most experts are encouraging the public to practice social distancing to “flatten the curve” – a phrase used to describe the attempt to distribute the lifespan of the outbreak more gradually over time so as not to overwhelm the health care system – some people have disagreed with that tactic.

Knut Wittkowski, a former biostatistician at the Rockefeller University, claimed social distancing is not the right way to handle the pandemic.

Wittkowski was quoted in a WND article – which cited a YouTube video and was shared extensively on Facebook – as saying that achieving herd immunity is the only thing that stops respiratory diseases like COVID-19. He advocated for schools to be opened because within weeks, enough people will have been exposed to the virus and achieved immunity to stop the spread of the virus.

The Rockefeller University released a statement on April 13 addressing Wittkowski’s claim and stating his views “do not represent the views of the Rockefeller University, its leadership, or its faculty.”

He is not alone in this belief.

Boris Johnson, the British prime minister who was recently hospitalized with COVID-19, seemed to endorsed a similar idea, although his chief scientific adviser later revoked the statement. Johnson initially justified the herd immunity tactic by explaining that strict behavioral restrictions might fatigue people so much that they eventually stop following the social distancing protocol.

And a group of more than 500 behavioral scientists published a letter that criticized Johnson’s justification of fatigue, citing a lack of evidence.

Similar herd immunity strategies have been adopted in Sweden, with considerable criticism.

Despite the condemnation, Wittkowski still stands by his claim, citing the difficulty of contact tracing and a current lack of a vaccine.

“We have to let nature do what otherwise the vaccine would do and that is create people who are immune because they went through a very mild form of the disease,” he said.

Uncertainty with COVID-19 herd immunity

Herd immunity occurs when a large portion of the population becomes immune to a disease or virus, stopping its spread because there are so few people who can contract it.

It is typically attained through vaccination, not widespread infection. For example, herd immunity for the measles is achieved when 19 out of 20 people receive the vaccination.

Wittkowski supported herd immunity through infection.

Although it is possible to achieve herd immunity through infection, “You don’t rely on the very deadly infectious agent to create an immune population,” Akiko Iwasaki, a virologist at the Yale School of Medicine, told the Atlantic.

Dan Barouch, director of the Center for Virology and Vaccine Research at Harvard University, said between the two options of achieving herd immunity through infection versus vaccination, “I would certainly advocate for the latter.”

Relying solely on herd immunity through widespread exposure to combat COVID-19 would overwhelm hospitals and put the elderly and people with preexisting conditions at risk.

The need for hospital beds varies from state to state. A USA TODAY analysis in March of data from the Census Bureau and the American Hospital Association found some states may need eight times as many beds to appropriately care for coronavirus patients if infection spreads at the rate of a mild flu. (The exact infection rate of COVID-19 is still unknown.) This estimate assumes all infections would occur at once and that all hospital beds are empty, both of which are false. 

Graham Medley leads a group of scientists who model the spread of infection diseases at the London School of Hygiene and Tropical Medicine. He explained to the Atlantic that herd immunity to the coronavirus may come as a consequence, but it should not be an aim.

The World Health Organization also raised questions about the herd immunity response. 

Margaret Harris, a spokesperson for the WHO, said in an interview with BBC she has doubts about achieving herd immunity through infection, referencing how too little is known about the virus to know if it would be effective.

And a letter signed by more than 500 scientists in the U.K. criticized the country’s move toward pursuing herd immunity. “Going for ‘herd immunity’ at this point does not seem a viable option, as this will put (Britain’s National Health Service) at an even stronger level of stress, risking many more lives than necessary.”

Herd immunity is also risky because little is known about natural protective immunity to the virus after it has been contracted. Exposing people to the virus in an attempt to reach herd immunity is potentially counterproductive if people can become infected again shortly after testing negative.

“With most viral infections, when someone gets infected and then recovers, they develop immunity at least for a period of time and cannot be reinfected. That’s true for most viruses. It’s not true for all viruses,” Barouch said. “For COVID-19 we don’t know yet. We don’t yet have definitive proof whether there’s natural protective immunity.”

James Whitney, principal investigator at the Center for Virology and Vaccine Research, agrees and said COVID-19’s unknown mutation rate also poses uncertainty for reaching herd immunity. 

“The short answer is we don’t know enough right now to say if infection will offer complete protection,” Whitney said. “Everyone walking around hoping to engender herd immunity is probably not the best scenario. I would say a vaccine is probably the best way and the most durable way to engender herd immunity.”

Our ruling: Partly false

We find the claim that herd immunity would stop COVID-19 rather than flattening the curve to be partly false. Although herd immunity may eventually be achieved, as a result of vaccination or widespread infection, other factors like access to testing and medical equipment, social distancing, quarantining and vaccination help stop respiratory diseases like COVID-19. Further, experts say too little is know about the novel coronavirus to ensure herd immunity would offer complete protection from infection.

Our fact-check sources:

• WND article, April 7, 2020
• Statement from the Rockefeller University, April 13, 2020
• The Atlantic article, March 16, 2020
• Open letter to the UK Government regarding COVID-19
• Al Jazeera article, April 14, 2020
• University of Oxford’s Vaccine Knowledge Project
• USA TODAY article, March 13, 2020
• The Guardian article, March 14, 2020
• Public request to take stronger measures of social distancing across the UK with immediate effect, March 14, 2020
• Interview, Dan Barouch, director of the Center for Virology and Vaccine Research at Harvard University, April 16, 2020
• Interview, James Whitney, principal Investigator for the Center for Virology and Vaccine Research, April 16, 2020
• Interview, Knut Wittkowski, former biostatistician at the Rockefeller University, April 17, 2020 
• Sweden’s government has tried a risky coronavirus strategy. It could backfire, Vox, April 16

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