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Herd Immunity is Unlikely in COVID-19

Researchers outline five key reasons why this theoretical benchmark for ending the pandemic might not be met

With COVID-19 vaccination rates on the rise it is natural to wonder: How much longer will this pandemic last? While we would like that to be soon, the once-popular idea that enough of us will gain immunity to SARS-CoV-2 either through vaccination or exposure to the virus--a threshold commonly referred to as herd immunity--appears less and less likely.  

In this article in Nature, the writer points out that independent data scientist Youyang Gu recently changed the name of his popular COVID-19 forecasting model from ‘Path to Herd Immunity’ to ‘Path to Normality’. Gu thinks that vaccine hesitancy, the emergence of new variants and the delayed arrival of vaccinations for children will probably mean that a herd immunity threshold of 70-80% won't be achieved.

Epidemiologists agree. “We’re moving away from the idea that we’ll hit the herd-immunity threshold and then the pandemic will go away for good,” says epidemiologist Lauren Ancel Meyers, executive director of the University of Texas at Austin COVID-19 Modeling Consortium.

This shift reflects the complexities and challenges of the pandemic, and shouldn’t overshadow the fact that vaccination is helping. “The vaccine will mean that the virus will start to dissipate on its own,” Meyers says. But as new variants arise and immunity from infections potentially wanes, “we may find ourselves months or a year down the road still battling the threat, and having to deal with future surges.