Allowing the virus to spread without containment increases the likelihood of such a mutation, which is itself a reason to push for herd immunity sooner rather than later. It’s not clear what percentage of the population needs to be immune to achieve herd immunity, but experts tend to agree it’s north of 70 percent. Of course there are also tens of millions of people who have some form of immunity from having contracted the virus. Again, that’s the race: As cases surge in the Northeast, can enough people be vaccinated to slow the virus’s spread and achieve herd immunity without the health repercussions of rampant infections? In other words, at least a quarter of the population should have immunity, unless existing natural immunity (from an infection) doesn’t protect against the new variants that are helping power the surge in the Northeast.

Source: Washington Post April 01, 2021 22:03 UTC