In the new paper, the scientists provided more evidence in favor of the virus having spilled over from an animal host outside of a laboratory. Joel Wertheim, a virologist at the University of California, San Diego, and a co-author, said that an important point in support of a natural origin was the “uncanny similarity” between the Covid and SARS pandemics. Both viruses emerged in China in the late fall, he said, with the first known cases popping up near animal markets in cities — Wuhan in the case of Covid, and Shenzen in the case of SARS.
In the SARS epidemic, the new paper points out scientists eventually traced the origin to viruses that infected bats far from Shenzen.
Based on the distribution of viruses similar to the new coronavirus across Asia, Dr. Wertheim and his colleagues predict the origin of SARS-CoV-2 will also be far from Wuhan.
Since first surfacing in the final months of 2019, this pandemic’s viral culprit has yet to be found naturally occurring in any animal.
In May, another team of 18 scientists published a letter arguing that the possibility of a lab leak needed to be taken seriously, because there was too little evidence to favor a natural origin of the coronavirus or a leak from a lab. Wuhan, where the pandemic was first documented, is home to the Wuhan Institute of Virology, or W.I.V. for short, where researchers have studied coronaviruses from bats for years.