Aerial view of Manaus, Amazonas state, Brazil,

on September 25, 2020. The Brazilian city of Manaus, which was devastated by the coronavirus pandemic, may have suffered so many infections that its population now benefits from “herd immunity,” according to a preliminary study. Published on the website medRxiv, the study analyzed infection data with mathematical modeling to estimate that 66 percent of the population had antibodies to the new coronavirus in Manaus, where the pandemic’s passage was as fast as it was brutal.