Virus World

A cemetery in Manaus, Brazil, has cleared ground (right) for the graves of people killed by COVID-19, which has devastated the city. As much as two-thirds of the population of Manaus, a city of two million people in Brazil’s state of Amazonas, could have been infected with the new coronavirus. That’s a proportion high enough to have contributed to controlling the spread of the virus.Ester Sabino at the University of São Paulo, Brazil, and her colleagues searched for antibodies against SARS-CoV-2 in more than 6,000 blood samples collected by a Manaus blood bank between February and August (L. F. Buss et al. Preprint at medRxiv https://doi.org/ghcm6h; 2020).

 

From the proportion of donors who tested positive for antibodies, the authors estimate that about 66% of the population had been infected by early August — months after the epidemic in Manaus peaked in May . The authors say that the high proportion of donors with antibodies to the virus suggests that Manaus might have reached ‘herd immunity’, the term for a scenario in which enough people are immune to an infection to control its spread. The team says its estimate accounts for several potential sources of bias, including false positives and false negatives in antibody testing. The findings have not yet been peer reviewed.

 

Preprint available at medRxiv (Sept. 21, 2020):

https://www.medrxiv.org/content/10.1101/2020.09.16.20194787v1