Also Read | Vaccine utilization rates lower in states witnessing second waveSARS-CoV-2 is a zoonotic coronavirus, believed to have jumped from an unknown animal host to humans.
Numerous efforts have been made to identify when the virus first began spreading among humans, based on investigations of early-diagnosed cases of covid-19.The first cluster of cases -- and the earliest sequenced SARS-CoV-2 genomes -- were associated with the Huanan Seafood Wholesale Market, but study authors said the market cluster is unlikely to have marked the beginning of the pandemic because the earliest documented covid-19 cases had no connection to the market."Our study was designed to answer the question of how long could SARS-CoV-2 have circulated in China.