US COVID-origins hearing renews debate over lab-leak hypothesis

Summary: Understanding the circumstances that lead to pandemics is crucial for their prevention. In this study, the genomic diversity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) early in the coronavirus disease 2019 (COVID-19) pandemic was analyzed. The results suggest that before February 2020, SARS-CoV-2 likely consisted of two distinct viral lineages, labeled A and B. Through phylodynamic rooting methods and epidemic simulations, it was revealed that these lineages were the result of at least two separate cross-species transmission events into humans. The findings indicate that widespread circulation of SARS-CoV-2 in humans before November 2019 is unlikely, and define the narrow time window between the first jump of SARS-CoV-2 into humans and the first reported cases of COVID-19.

Summary: This article demonstrates that the SARS-CoV-2 virus originated from the Huanan Seafood Wholesale Market in Wuhan, China, where susceptible animals were sold in late 2019, and SARS-CoV-2-positive environmental samples were spatially associated with vendors selling live animals.