As 2019 turned into 2020, a coronavirus spilled over from wild animals into people, sparking what has become one of the best documented pandemics to afflict humans. However, the origins of the pandemic in December 2019 are controversial. Worobey et al. amassed the variety of evidence from the City of Wuhan, China, where the first human infections were reported. These reports confirm that most of the earliest human cases centered around the Huanan Seafood Wholesale Market. Within the market, the data statistically located the earliest human cases to one section where vendors of live wild animals congregated and where virus-positive environmental samples concentrated. In a related report, Pekar et al. found that genomic diversity before February 2020 comprised two distinct viral lineages, A and B, which were the result of at least two separate cross-species transmission events into humans (see the Perspective by Jiang and Wang). The precise events surrounding virus spillover will always be clouded, but all of the circumstantial evidence so far points to more than one zoonotic event occurring in Huanan market in Wuhan, China, likely during November–December 2019. —CA




Understanding how severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) emerged in 2019 is critical to preventing future zoonotic outbreaks before they become the next pandemic. The Huanan Seafood Wholesale Market in Wuhan, China, was identified as a likely source of cases in early reports, but later this conclusion became controversial. We show here that the earliest known COVID-19 cases from December 2019, including those without reported direct links, were geographically centered on this market. We report that live SARS-CoV-2–susceptible mammals were sold at the market in late 2019 and that within the market, SARS-CoV-2–positive environmental samples were spatially associated with vendors selling live mammals. Although there is insufficient evidence to define upstream events, and exact circumstances remain obscure, our analyses indicate that the emergence of SARS-CoV-2 occurred through the live wildlife trade in China and show that the Huanan market was the epicenter of the COVID-19 pandemic.

On the Controversies Surrounding the Lab-Leak Theory of COVID-19
Jin-Hong Yoo 1,✉
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PMCID: PMC12040609  PMID: 40296830
In April 2025, the White House of the United States officially declared on its website that COVID-19 originated from a laboratory in Wuhan, China.1 This announcement has sparked significant controversy, as it may be seen as a case where political considerations have influenced, or at least appeared to influence, the interpretation of scientific matters.

The origin of COVID-19 remains a topic of vigorous scientific debate. The most widely supported theory is the natural spillover hypothesis, which posits that the virus was transmitted to humans through a process of accumulated mutations while circulating among animals. This theory is backed by numerous genomic analyses and evolutionary biology studies that support the natural emergence of SARS-CoV-2,2,3,4,5 with concrete evidence showing adaptation processes through recombination events among various hosts such as bats and pangolins.