Variant identified in Brazil is doubly infectiousBetween November and January in Manaus, Brazil, the frequency of COVID-19 cases involving the P.1 coronavirus variant increased from non-existent to 73%, and the number of infections there quadrupled compared to what the city experienced in the first wave of the pandemic, according to a report posted on medRxiv ahead of peer review.The greater infectiousness of the P.1 variant likely contributed to that, the report suggests.Based on national health surveillance data, the authors estimate that the P.1 variant is roughly 2.5 times more transmissible than previous variants circulating in Manaus.The spread of P.1 occurred despite the fact that 68% of the city's population had already been.