The variant of concern (VOC) P.1 emerged in the Amazonas state (Brazil) in November-2020. It contains a constellation of mutations, ten of them in the spike protein. Consequences of these specific mutations at the population level have been little studied so far, despite the detection of P.1 variant in 26 countries, with local transmission in at least four other countries in the Americas and Europe. Here, we estimate P.1's transmissibility and reinfection using a model-based approach, by fitting data from the Brazilian national health surveillance of hospitalized individuals and frequency of the P.1 variant in Manaus from December 2020 to February 2021, when the city was devastated by four times more cases than in the previous peak (April 2020). The new variant was found to be about 2.6 times more transmissible (95\% Confidence Interval (CI): 2.4--2.8) than previous circulating variant(s). The city already had a high prevalence of individuals previously affected by the SARS-CoV-2 virus (estimated as 78\%, CI:73--83\%), and the fitted model attributed 28\% of the cases during the period to reinfections by the variant P.1. Our estimates rank P.1 as the most transmissible among the current identified SARS-CoV-2 VOCs, posing a serious threat and requiring urgent measures to control its global spread.

中文翻译：

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基于模型的SARS-CoV-2 P.1变种传播和再感染的估计

关注的变种（VOC）P.1于2020年11月在亚马逊州（巴西）出现。它包含一组突变，其中十个突变存在于刺突蛋白中。尽管在26个国家中发现了P.1变体，并且在美洲和欧洲的至少其他四个国家中发生了局部传播，但到目前为止，在人群水平上对这些特定突变的后果尚未进行研究。在这里，我们采用基于模型的方法估算P.1的传播性和再感染性，方法是拟合2020年12月至2021年2月在马瑙斯的巴西全国住院病人个人健康监测数据和P.1变种的频率。与上一个高峰期（2020年4月）相比，遭受破坏的案件多四倍。发现新变体的可传播性约为2.6倍（95％置信区间（CI）：2.4--2.8）。该城市以前受SARS-CoV-2病毒感染的人群已经很高（估计为78％，CI：73--83 \％），该拟合模型在此期间占该病例的28％ P.1变种引起的再感染。我们的估计将P.1列为当前确定的SARS-CoV-2 VOC中最易传播的病毒，这构成了严重威胁，需要采取紧急措施来控制其全球扩散。