From TPM Reader KR …
The two studies, published last year in Science, are highly technical but Dr. Steve Novella breaks down at Science Based Medicine. Taken together they are a “body blow”, he says, to the lab leak hypothesis.
The first study used genetic analysis of the virus in the earliest cases to trace their origin and spread. You can use genetic analysis to trace spread as the virus mutates rapidly, splitting off into branching subtypes identifiable by genetic markers. This analysis finds that there were very likely two distinct spillover events, not just one, although they happened close together in space and time – in Wuhan in late November and early December 2019. The authors conclude:
“These findings indicate that it is unlikely that SARS-CoV-2 circulated widely in humans prior to November 2019 and define the narrow window between when SARS-CoV-2 first jumped into humans and when the first cases of COVID-19 were reported. As with other coronaviruses, SARS-CoV-2 emergence likely resulted from multiple zoonotic events.”
This is a body blow to the lab leak hypothesis. The second study then delivers the knock-out punch. They tracked the earliest cases of COVID, and also looked at environmental DNA samples to track where the virus may have been at the time. They found:
“We report that live SARS-CoV-2 susceptible mammals were sold at the market in late 2019 and, within the market, SARS-CoV-2-positive environmental samples were spatially associated with vendors selling live mammals. While there is insufficient evidence to define upstream events, and exact circumstances remain obscure, our analyses indicate that the emergence of SARS-CoV-2 occurred via the live wildlife trade in China, and show that the Huanan market was the epicenter of the COVID-19 pandemic.”
Their evidence shows the virus was in the market and the first cases likely occurred in the market. Lead author Michael Worobey characterized the data this way:
“In a city covering more than 3,000 sq miles (7,770 sq km), the area with the highest probability of containing the home of someone who had one of the earliest Covid-19 cases in the world was an area of a few city blocks, with the Huanan market smack dab inside it.”
The data is even visually compelling, as you can see from the main image. This data is almost impossible to align with the lab-leak hypothesis. You would have to believe that there were two lab-leak events, both of which promptly went to the Huanan market and spread the virus. That represents epic-level special pleading, and is not sound epidemiological reasoning.
At this point the lab-leak hypothesis should be scientifically dead. The dominant hypothesis, that COVID resulted from zoonotic spillover events in the Huanan market, has now emerged as a fairly solid conclusion. This is critical to understand, as it relates to our efforts to prevent future spillover events. There were more than 47,000 individual live animals from 38 different species sold in the Huanan market between May 2017 and November 2019 in the market. Further, the conditions were often unhygienic and unsafe. This is exactly the kind of close contact between animals and humans the predispose to zoonotic spillover events.