Faria and his colleagues started tracking the coronavirus when it exploded in Brazil last spring. Manaus, a city of 2 million in the Brazilian Amazon, was hit particularly hard. At its springtime peak, the cemeteries of Manaus were overwhelmed by the bodies of the dead.
But after a peak in late April, Manaus seemed to have gotten past the worst of the pandemic. Some scientists thought that the drop meant Manaus had gained herd immunity.
Faria and his colleagues looked for coronavirus antibodies in samples from a Manaus blood bank in June and October. They determined that roughly three-quarters of the residents of Manaus had been infected.
But near the end of 2020, new cases began surging again. “There were actually far more cases than in the previous peak of cases, which had been in late April,” Faria said. “And that was very puzzling to us.”
Faria and his colleagues wondered if new variants might be partly to blame for the resurgence. In Britain, researchers were finding that B.1.1.7 was surging across the country.
To search for variants, Faria and his colleagues started a new genome sequencing effort in the city. While B.1.1.7 had arrived in other parts of Brazil, they didn’t find it in Manaus. Instead, they found a variant no one had seen before.
Many variants in their samples shared a set of 21 mutations not seen in other viruses circulating in Brazil. Faria sent a text message to a colleague: “I think I’m looking at something really strange, and I’m quite worried about this.”
A few mutations in particular worried him, because scientists had already found them in either B.1.1.7 or B.1.351. Experiments suggested that some of the P1 mutations might make the variants better able to infect cells. Other P1 mutations let them evade antibodies from previous infections or produced by vaccines.
https://sg.news.yahoo.com/virus-variant-brazil-infected-many-132136413.html
