COVID-19 Asked & Answered: Is herd immunity possible with COVID-19?

April 27, 2021

With vaccines increasingly available across the United States and if people also continue to follow masking and distancing requirements, Ottar Bjornstad, distinguished professor of entomology and biology, shares that while it’s a highly optimistic scenario, it’s possible we could see reduced COVID-19 transmission by the end of summer 2021. 

Herd immunity occurs when enough people are immune to an infectious disease that the virus can no longer spread, and scientists do not yet know how many people will need to be immune to COVID-19 to truly reach herd immunity. It could be quite high; for instance, maintaining herd immunity for measles requires that 95% of the population be immune. 

“Unfortunately, if vaccination rates do not continue to improve and people don’t adhere to public health guidelines, the virus will have more time to circulate in the population,” Bjornstad adds. “This, in turn, will give the virus opportunities to evolve into more variants that may be more infectious. The good news is that if we all do our part, we can continue to protect more and more people, and that should be the goal.” 

The latest COVID-19 vaccination information for the Penn State community is available on the University’s coronavirus information website.

Last Updated April 27, 2021