Monday, August 17, 2020

What if ‘Herd Immunity’ Is Closer Than Scientists Thought?

In what may be the world’s most important math puzzle, researchers are trying to figure out how many people in a community must be immune before the coronavirus fades.

The Borough Park neighborhood of Brooklyn was hit hard by the coronavirus, reaching thousands of cases and hundreds of deaths by April. Credit...Jonah Markowitz for The New York Times

By Apoorva Mandavilli

We’ve known from the beginning how the end will arrive. Eventually, the coronavirus will be unable to find enough susceptible hosts to survive, fading out wherever it briefly emerges.

To achieve so-called herd immunity — the point at which the virus can no longer spread because there are not enough vulnerable humans — scientists have suggested that perhaps 70 percent of a given population must be immune, through vaccination or because they survived the infection.

Now some researchers are wrestling with a hopeful possibility. In interviews with The New York Times, more than a dozen scientists said that the threshold is likely to be much lower: just 50 percent, perhaps even less. If that’s true, then it may be possible to turn back the coronavirus more quickly than once thought.

The new estimates result from complicated statistical modeling of the pandemic, and the models have all taken divergent approaches, yielding inconsistent estimates. It is not certain that any community in the world has enough residents now immune to the virus to resist a second wave.  Read more >>