A Brazilian City May Have Achieved Herd Immunity to COVID-19 — But Not Without a Cost

Updated September 23, 2020

Thomas A. Russo, MD, professor of medicine and chief of the Division of Infectious Diseases, is quoted in a story on the Brazilian city of Manaus and the possibility that the city may have achieved herd immunity against COVID-19. A new study that was posted as a preprint, meaning that it has not yet been published in a peer-reviewed journal, shows that antibody tests indicate that up to two-thirds of the population of Manaus may have caught the novel coronavirus, and that this may explain a sustained decline in new cases there, according to Popular Science. "It’s a little difficult to tease out if this is pure herd immunity versus a combination of things. But it’s intriguing for sure," Russo says.”