Origin of COVID-19
Since the beginning of the COVID-19 pandemic, there have been efforts by scientists, governments, and others to determine the origin of the SARS-CoV-2 virus. Similar to other outbreaks,[1][2][3] the virus was derived from a bat-borne virus and most likely was transmitted to humans via another animal in nature, or during wildlife trade such as that in food markets.[11] While other explanations, such as speculations that SARS-CoV-2 was accidentally released from a laboratory have been proposed,[12][13][14] such explanations are not supported by evidence.[15] Conspiracy theories about the virus's origin have also proliferated.[16]
SARS-CoV-2 has close genetic similarity to multiple previously identified bat coronaviruses, suggesting it crossed over into humans from bats.[7][17][18][19][20] Research is ongoing as to whether SARS-CoV-2 came directly from bats or indirectly through an intermediate host, such as pangolins,[21] civets,[22] or raccoon dogs.[23][24] Genomic sequence evidence indicates the spillover event introducing SARS-CoV-2 to humans likely occurred in late 2019.[25][26] As with the 2002–2004 SARS-CoV-1 outbreak, efforts to trace the specific geographic and taxonomic origins of SARS-CoV-2 could take years, and results may be inconclusive.[27]
In July 2022, two papers published in Science described novel epidemiological and genetic evidence that suggested the pandemic likely began at the Huanan Seafood Wholesale Market and did not come from a laboratory.[28][29][30]