What is herd immunity and could it help slow the coronavirus pandemic?

As the coronavirus pandemic continues to spread and the U.S. implements social distancing measures, some world leaders have mentioned herd immunity as a way to slow the virus.

Herd immunity is when enough of a population becomes immune to a disease through vaccine or already getting sick to make the spread unlikely between people in the community, according to the Centers for Disease Control and Prevention. Herd immunity also protects newborns and people who can’t be vaccinated because it helps decrease person-to-person spread, the CDC said.

The United Kingdom initially didn’t implement social distancing or shut down large gatherings due to trying to build herd immunity, according to National Geographic.

Sir Patrick Vallance, the U.K.’s chief scientific adviser told Sky News “probably about 60%” of the population would need to be infected in order to attain herd immunity.

The country ultimately switched from the strategy to use suppression techniques after models predicted the national health care system would be overwhelmed with cases, according to the BBC.

Has herd immunity worked in previous epidemics?

Herd immunity worked for Norway during the swine flu epidemic through natural immunity and vaccination, according to Heathline.

However, herd immunity doesn’t work against every illness and isn’t good enough alternative to getting vaccinated, Healthline reported.

Some health experts say herd immunity isn’t the best strategy to count on to stop this virus, Business Insider reported.

“They’re making a big assumption ... young people can get the disease and won’t die,” Natalie Dean, a biostatistician at the University of Florida who specializes in infectious disease epidemiology, told Business Insider. “We don’t have enough data to support that. We’re seeing 30-year-olds in the ICU and we don’t know if those people aren’t going to have long-term breathing problems and lung problems.”

This story was originally published April 8, 2020 at 11:16 AM with the headline "What is herd immunity and could it help slow the coronavirus pandemic?."