Did the coronavirus responsible for the COVID-19 pandemic originate from live animals for sale in the Huanan Seafood Market in Wuhan, China, or as a lab leak from the Wuhan Institute for Virology? In search of answer to this question, a new article in Science parses the early outbreak data along with environmental samples taken in Huanan Market supplied by Chinese researchers. It finds that the market was the "epicenter" for the contagion. A second article concludes that the outbreak began after two genetically distinct coronaviruses infected people beginning in November and December of 2019.
Do these findings rule out the possibility that the COVID-19 coronavirus originated from the institute? No. The first article acknowledges that "events upstream of the market, as well as exact circumstances at the market, remain obscure, highlighting the need for further studies to understand and lower the risk of future pandemics." Those "events upstream" could include a scenario in which someone associated with the Virology Institute was unknowingly infected with the virus and carried it to the market while shopping.
"Have we disproven the lab leak theory? No, we have not," one of the study's authors told The Washington Post. "Will we ever be able to? No. But there are 'possible' scenarios and there are 'plausible' scenarios….'Possible' does not mean equally likely."
Skeptics of the natural origin of the virus will point to its novel furin cleavage site (FCS), which enhances its ability to latch onto and infect human cells. Broad Institute researcher Yujia Alina Chan and her colleagues noted in a January 2022 article for Molecular Biology and Evolution that the Wuhan Institute had earlier proposed to research FCS in coronaviruses found in bats. They further observed that the FCS has not been found so far in plausible evolutionary forebears of the COVID-19 coronavirus.
On the other hand, a May 2022 analysis of the genetics of bat coronaviruses in Communications Biology identifies "several possible ways for natural acquisition of the FCS" in bat coronaviruses. This, they argue, supports "a natural evolutionary origin from bats with or without the involvement of [other animal] intermediary hosts."
In June, the World Health Organization urged the Chinese government and researchers to allay speculations about lab leaks by being more forthcoming about the work on coronavirus viruses undertaken at the Wuhan Institute for Virology. The world is still waiting to hear from them.