Daniel Arlein has already had COVID-19. In March, the 36-year-old small business owner and DJ, who lives in Brooklyn, tested positive for the viral infection .... //

Since the new coronavirus is highly contagious (meaning a large percentage of the population would have to get it to slow its spread), the human toll of reaching herd immunity without a vaccine would be staggering. And that’s assuming that once a person gets sick, they stay immune for a long time. But at this point, we don’t know if that’s the case. //

“The disease sort of stops increasing at the point when you reach herd immunity, but there’s still lots and lots of people infected. It only slowly goes down, and on its way down, [it] infects another third of the population,” said Richard Neher, an evolutionary biologist at the University of Basel in Switzerland. “If you drive a car and suddenly you switch off the engine, it doesn’t stop instantly.” //