You asked, we answered: Does vaccine herd immunity work?

Graphic of a world map


I have read that it is important that a large percentage of people get the vaccine. It is not clear to me why. If I get it and, say, only 50% of the population chooses to get it, then I am protected, others are protected from me, and the health care system will not be overwhelmed. So it seems to me that herd immunity through a vaccine is unimportant from a personal and public policy point of view since the only people remaining at risk have chosen to be at risk.

Answered by infectious diseases expert Sara Bares, MD

To end this pandemic, a large percentage of the population needs to either be vaccinated or gain immunity through infection with the virus. The second is a much deadlier and needlessly severe option. With enough people immune to infection, the chain of transmission is stopped. Herd immunity provides indirect protection to individuals who aren't immune, including those who can't receive the vaccine and/or those who are immunocompromised and potentially unable to mount a strong immune response to the vaccine.

If the virus keeps circulating unchecked, mutations will continue to be introduced. This could potentially introduce new strains that resist the vaccines we have now. It would be much better to eliminate COVID-19 from the population through herd immunity than to have the virus continuing to spread in unvaccinated people.