The slow redefinition of ‘herd immunity’ — and what’s actually possible in the United States

“I would like to get people away from this concept of referring to something that it is very elusive in its definition,” said Anthony S. Fauci, the country’s top infectious-disease expert, “We’ve made estimates that [herd immunity] is somewhere between 70 and 85 percent, but we don’t know that as a fact. So that rather than concentrating on an elusive number, let’s get as many people vaccinated as quickly as we possibly can.”

Source: WP