According to a study uploaded to GitHub on February 27 that has not been peer reviewed, an emerging variant of SARS-CoV-2 first spotted in November in Manaus, Brazil and known as P.1 is around twice as transmissible as the variant that gripped the country last spring. Manaus experienced another surge of cases in December, and the study’s model predicts that P.1 could evade antibodies from previous infections 25–61 percent of the time, perhaps pointing to reinfections as a driver of the recent COVID-19 wave.
The Guardian reports that many of the mutations that affect the variant’s spike protein are the same as those found in the B.1.351 variant first identified in South Africa. The study's authors write that three of the mutations allow the virus to more easily bind to the ACE2 receptor on human cells. ACE2 is a surface protein on cells in many tissues, including the lungs, heart, and blood vessels. When the virus binds to that protein, it opens up the cell to infection.
P.1 is not isolated to Brazil and has been identified in six cases from five US states, another six individuals in the UK, and in 23 other countries, The New York Times reports. It is not yet known how these variants will affect outbreaks in these countries, and not all experts are sounding alarms quite yet.
“You need many introductions [of a virus] to start an epidemic,” coauthor Ester Sabino of the University of São Paulo tells BBC. “Six is very few. I would say if you take care and do contact tracing, this is going to decrease.”
Through genomic modeling, Sabino and her colleagues were able to find that P.1 emerged in Manaus in November and December and stayed within the region through the end of the year. Epidemiological modeling and sample viral loads from patients indicate that the variant is more transmissible than the variant that gripped much of the world in 2020 and could be linked to worse outcomes and an increased likelihood of surpassing immunity from a past SARS-CoV-2 infection. While the models were built around COVID-19 in Manaus, the authors say this is a variant of concern wherever there are active cases of P.1.
As vaccine rollouts surge around the globe and cases and hospitalizations drop accordingly, there could be a chance to drastically reduce infections before another variant has a chance to take hold. The two vaccines approved for use in Brazil are Oxford/AstraZeneca’s, which is 60–90 percent effective at staving off serious illness, and Sinovac’s from China, which is 50 percent effective in Brazil. There has not been any clinical research yet on how the Pfizer/BioNTech, Moderna, or Johnson & Johnson shots—the three vaccines approved for use in the US—will fare when faced with P.1.
“Our current vaccines have not yet been studied against this variant and we’re working to understand what impact it might have, but we do know that this variant has caused significant challenges in Brazil,” UK Health Secretary Matt Hancock, who was not part of the study, tells BBC. “We’re doing all we can to stop the spread of this new variant in the UK, to analyse its effects and to develop an updated vaccine that works on all these variants of concern and protect the progress that we’ve made as a nation.”