n the days after February 4, the summary document written by Holmes and his colleagues continued to circulate among the scientists and health officials, including Collins and Fauci, as it was revised and reworked. The scientists were now contemplating three main hypotheses for the virus’s origin—two involving a natural spillover event and one involving a lab origin. They hypothesized that it jumped from its original host, likely a bat, directly into humans, where it evolved its pandemic potential; that it spilled from its original host into some intermediate animal host before jumping into humans; or that it was the result of some sort of lab accident involving serial passage. The scientists wrote that “current data are consistent with all three” scenarios.
On February 7, Farrar notified Fauci and Collins that new preliminary data had come in from China concerning coronaviruses found in pangolins, one of the world’s most heavily trafficked mammals. It seemed to excite the scientists: “Reports coming out overnight that Chinese group have pangolin viruses that are 99% similar,” Farrar wrote. “This would be a crucially important finding and if true could be the ‘missing link’ and explain a natural evolutionary link.”
“That will be VERY interesting,” Collins responded. “Does it have the furin cleavage site?”
The pangolin data, it turned out, did not provide an explanation for the scientists’ central concerns about the furin cleavage site, and the viruses isolated from some pangolins were not 99 percent similar to SARS-CoV-2, but the data did show that coronaviruses circulating in pangolins shared other key features with the pandemic virus. This seems to have played an important role in shifting the scientists’ thinking away from the lab hypothesis.
Holmes, who had been described in an earlier e-mail as being “60:40 lab side,” wrote, “Personally, with the pangolin virus possessing 6/6 key sites in the receptor binding domain, I am in favour of the natural evolution theory.”
