Public discussion of “herd immunity” often treats it as an on-off switch: When the US achieves herd immunity, the crisis will be over; until then, the country has little immunity to Covid-19. Herd immunity is more like a light dimmer. The more people develop immunity – either through infection or vaccination – the less easily the virus will spread. Nearly 30 percent of Americans have now had the virus, according to Youyang Gu, a data scientist. There is some overlap between these two groups, meaning: about 40 percent of Americans now have some protection from Covid.

Source: New York Times November 25, 2021 01:20 UTC