According to a study published on Wednesday, 66% of the inhabitants of Manaus, in northern Brazil, have antibodies against coronavirus, which makes it possible to control viral circulation.
Residents of the Brazilian city of Manaus, which is heavily infected with the coronavirus, are now taking advantage of a level of collective immunity to control viral circulation, according to a preliminary study published on Wednesday on sitemedRxiv.
About 66% of the population have antibodies to coronavirus, a rate that is high enough that the disease can no longer be spread effectively, says the group of 34 Brazilian and international researchers, authors of the study. However, their research has not yet been reviewed by colleagues.
Dramatic reduction in the number of deaths
Located in the Amazon rainforest, Manaus was the site of images of overwhelmed hospitals, corpses stacked in refrigerated trucks and mass graves when the epidemic there was at its peak in May.
Manaus has registered 2462 deaths from Covid-19. If it were a country, it would have the second highest mortality rate in the world, with 100.7 deaths per 100,000 inhabitants. But the number of deaths in the city of 2.2 million has dropped dramatically in recent weeks to an average of 3.6 per day in the last fourteen days.
“It seems that the exposure to the virus itself has led to a reduction in the number of new cases and deaths in Manaus,” said study coordinator, medical professor Ester in São Paulo. Sabino, at the São Paulo State Research Support Foundation (Fapesp) who helped fund the study.
“Collective immunity through natural infection is not a strategy”
Manaus is one of Brazil’s fastest-defining cities, but for health experts, it would be a dangerous path for decision-makers to seek herd immunity.
“Collective immunity through natural infection is not a strategy, it is a sign that a government has failed to control an epidemic and that it is paying the price in lost lives,” tweeted Florian Krammer, professor of microbiology at the Icahn School of Medicine at Mount Sinai Hospital in New York.
Because I already see it going like this: I do not support society’s immunity as a strategy. Community immunity through natural infection is not a strategy, it is a sign that a government has failed to control an outbreak and is paying for it in lost lives. https://t.co/o0hxHHTaho
– Florian Krammer (@florian_krammer) September 22, 2020
Other experts have also warned that immunity may be short-lived after infection. Brazil is the second most distressed country in the world by the pandemic, behind the United States, with more than 138,000 deaths.