Laboratory tests have found that the Brazilian-derived variant of coronavirus P.1 may infect some people who have been immune to previous COVID-19 infections.
The New York Times reports that the discovery was made during research into the rapid outbreak of strain P.1 in the city of Manaus, Brazil, where it dominated because it was more contagious.
Nuno Faria, a virologist at Imperial College London and a researcher who helped lead much of P.1. studies, told the Times that the latest findings apply to Manaus. He said he was not sure if they mattered elsewhere.
Faria and colleagues note that Manaus appears to have overcome the worst of the pandemic since it peaked in April last year, only to increase in cases again in late 2020. The increase in cases leads researchers to suspect that had a new variant arose.
After studying variant genomes and medical records, the researchers concluded that variant P.1
The researchers confirmed their conclusion by mixing P.1 viruses with antibodies derived from people who had coronavirus last year and found that the antibodies were six times less effective at stopping coronavirus P.1.
The authors warn that the study, which was not published in a medical journal, was performed only on cells in laboratories and not on humans.
According to Faria, the risk of P.1 outbreaks can be reduced by doubling existing virus mitigation methods, including masks, social distancing and vaccinations.
“The final message is that you need to step up all vaccination efforts as soon as possible,” Faria said. “You have to be one step ahead of the virus.”
The Brazilian strain has already made its way to dozens of other countries, including the United States, which has reported cases of variant P.1 in Alaska, Florida, Maryland, Minnesota and Oklahoma.
According to the Centers for Disease Control and Prevention, 10 cases with option P.1 have been reported so far in the United States.