Evolutionary virologist Michael Worobey is trying to bring the debate about the origins of the pandemic back to where it started: with the notion that the coronavirus made the leap to humans at the Huanan Seafood Market in Wuhan, China. Last week, he argued in Sciences that, contrary to official infection deadlines, the “first known patient” was a market vendor selling shrimp. For Worobey, it is telling, to say the least, that this confirmed case, and most of the former, were related to Huanan. In an interview with Jane Qiu, whose excellent summary of the new analysis appeared Friday in the MIT Technology ReviewHe calls a natural spill at this location “much more likely than any other scenario based on what we now know.”
But the mystery is hardly solved. The Sciences The piece does not say that the shrimp seller was patient zero in the outbreak. In fact, Worobey’s previous work suggests that the first infection in general, whatever its source, must have occurred weeks before, in October or November 2019. And although many of the first known COVID-19 patients were connected to the market, some were not. .
Worobey’s analysis, which corroborates the work of several independent researchers, then, does not refute the possibility that the pandemic started from some other source, such as a laboratory accident. However, it does serve to crystallize the underlying structure of this endless and confusing argument. Those who are inclined to think, like Worobey, that the pandemic must have started from a commercialized wild animal share a fundamental intuition with those who point the finger at the laboratory: They both looked at all the facts and then identified a big coincidence, and they both believe that their theory, and only their theory, can explain it.
A single question seems to be the fuel for every fight: What are the odds? “Start with geography,” suggested science journalist Nicholas Wade in May. What are the odds, he and others ask, that a global outbreak of the bat-derived SARS-CoV-2 coronavirus will start within a few miles of the Wuhan Institute of Virology, the world’s largest BSL-4 facility, and research? ? home of the world’s leading researcher on bat coronavirus? Now keep in mind that scientists from this same facility were involved in efforts, both proposed and completed, to tinker with the genomes of similar viruses and see if they became more infectious. And note that these same scientists had identified one of the pandemic virus’s closest known relatives in a copper mine some 1,000 miles away. What are the odds? Quoth Wade: “It’s an exaggeration.”
Last week’s Worobey article makes a similar kind of argument. What are the odds? Start, once again, with geography. What are the odds that, if the virus emerged from the Wuhan Institute of Virology, the first known cases would appear more than eight miles away, in a market complex across a river from the putative site of any ” incident associated with the laboratory “? ? Now keep in mind that this market complex, in particular, is one of less than two dozen in Wuhan, a city of 11 million people, known to have trafficked live wild mammals in November 2019; and that Chinese health officials had brought an Australian virologist into this same market five years earlier, telling him, as he recalled in a recent interview with Qiu, that it was “a possible place that could trigger future outbreaks”; and also that most of Huanan’s cases were confined to the western section of the market, which, according to the joint study by China and the World Health Organization on the origins of the pandemic, housed seven of the 10 stalls in which wildlife products were sold. What are the odds?
In short, how likely is it that the first known outbreak in Wuhan will arise not inside a stadium, a department store, or some generic shopping mall, but in a market that sells live raccoon dogs, marmots, and hedgehogs? ? How come our timeline begins in one of the few places in this entire metropolis where plus Are you expecting to see a natural flooding event, the same type that caused the first SARS coronavirus outbreak? “Seems like too much of a coincidence”Qiu wrote on Twitter on Friday. Worobey told me by email that this was the “focal point” of his article. “At 10x magnification, it may seem surprising that the outbreak started in Wuhan, the site of the Wuhan Institute of Virology,” he said. “But at 100x magnification, it is the market that seems to be the epicenter.”
Two competing circumstantial arguments now face off like a pair of Milu deer in heat with their antlers locked, slapping each other. So, for example, those who defend the market theory will point out that Wade’s alleged “stretch”, the one involved in bringing SARS-CoV-2 to Wuhan,recap what happened 17 years before, when the original SARS virus first appeared in urban centers that were also nearly 1,000 miles from any bat caves in Yunnan. Or you will notice that the Wuhan Institute of Virology is far from the only place in China for coronavirus research. In other words: your match is not as unlikely as you think.
Then the picky eater goes backwards. Although most of the Huanan market cases, like most of the suspected stalls, were in the western section, that section itself contains hundreds of other stalls and spans an area the size of several city blocks. The cases in that section weren’t even clustered close to wildlife vendors, Alina Chan, a molecular biologist at the Broad Institute of MIT and Harvard and a co-author of Viral: The search for the origin of COVID-19he said when I texted him this week. (Worobey says that’s not surprising, given that most infections would have gone undetected.) Evolutionary virologist Jesse Bloom of the Fred Hutchinson Cancer Research Center in Seattle points out that the versions of SARS-CoV-2 obtained from Huanan samples are clearly on the market. not ancestral sources for all subsequent infections. “Certainly there is nothing in the sequence data that can disprove the idea that the first infections were in the Huanan market,” he told me, “but there is also nothing in the sequences that really suggests that it was in the market. “Once again: don’t embellish your coincidence.
The mere existence of these two opposing arguments does not make them the same. One match may appear larger than the other and is therefore more likely to reflect the true origins of COVID-19. I tend to think that market theory carries a bit more weight based on what we know now, but what we know now is limited to disclosures by the Chinese authorities. This is very clear: both circumstantial cases, for a laboratory origin and for a market spill, have been presented in the absence of crucial evidence that could very well exist.
We know that the Wuhan Institute of Virology public database of thousands of bat coronavirus sampled sequences has been offline since September 2019, and no one can explain why; that the key facts related to his investigation have only been revealed through the tenacious work of outside journalists and scientists; and that the blood samples of their workers, apparently negative for SARS-CoV-2, were not shared with international researchers.
Market theorists are also working in the dark. If wildlife vendors in Huanan were ever tested for antibodies, those results have been kept secret, and although the joint WHO-China study (released in March) claimed there was no illegal wildlife trade there , an article published in June contained photographic evidence of caged pig badgers and other wild mammals there. That document, by Xiao Xiao of China West Normal University, and several colleagues, does not say exactly where in the market those cages were found and if they were close to the first known victims of the outbreak. (One of the co-authors, Chris Newman of the University of Oxford, told me that he assumes that larger-scale data might exist, but that Xiao “has unfortunately been advised by his University not to add fuel to the media fire” to discuss them.)
It is quite possible that China has an interest in withholding evidence of both theories about the origin of the pandemic. (After all, each involves official negligence in its own way.) In other words, we could be stuck in a circumstantial stalemate. If one of these great coincidences points to the truth, what are the chances that we will find out?