The Brazilian city of Manaus, which months ago had its health and funeral services collapsed by the new coronavirus pandemic, could have achieved herd immunity with 66% of its population infected, according to a study presented on Tuesday. But that would be a Pyrrhic victory.
The study, conducted by an international group and led by researchers from the University of Sao Paulo (USP), said that the capital of the state of Amazonas experienced the peak of the curve in mid-May, when about 46% of its inhabitants had already contracted SARS-CoV-2.
In June it rose to 65% and in the following two months remained at around 66%, suggesting that the city, which has a population of around two million, may have achieved collective immunity from Covid.
“The exposure to the virus itself caused a drop in the number of new cases and deaths in Manaus. However, our results indicate a prevalence much higher than that estimated in previous studies,” said USP professor Ester Sabino, coordinator of the research.
The results of the research, which was supported by the Fundação de Amparo a la Pesquisa do Estado de São Paulo (FAPESP) and published on the medRxiv platform, are the result of a combination of mathematical models and serological analyses performed between February and August from blood samples.