Comment by American Association for the Advancement of Science

Two studies published in Science by Michael Worobey et al. and Jonathan Pekar et al. use complementary approaches – involving spatial and environmental analyses, as well as molecular analyses – to provide evidence that the Huanan market in Wuhan, China, was the early epicenter for the COVID-19 pandemic. The scientists concluded that SARS-CoV-2 was very likely present in live mammals sold at this market in late 2019 and suggest the virus spilled over into people working or shopping there from two separate zoonotic transmissions, in which lineage A and B progenitor viruses were both circulating in non-human mammals prior to their introduction into humans.