Thread by @MichaelWorobey

I wrote a Perspective on the origin of COVID just released in @ScienceMagazine

science.org/doi/10.1126/sc…

I have spent the last few months trying to poke holes in the hypothesis of a natural origin of SARS-CoV-2 by asking:

Was the apparent preponderance of early cases linked to Huanan Market real or just a mirage because that is where people were looking for cases?

This is a key question, because if the pattern is real, it is *very* hard to explain why we would observe it if the outbreak had not started at the market, in particular the western section where illegal wildlife like raccoon dogs was sold. It's about the size of a Home Depot.

You can’t explain away the preponderance of early cases linked to Huanan Market—as so many people, from Chinese authorities and scientists, to believers in a lab origin, have done Most of earliest cases really were linked to the market.

Many have dismissed the idea of the virus emerging at the market by arguing that all the focus by epidemiologists on the market led to lots of cases being identified there, while a vast number of cases elsewhere in the city were missed. This is just not true.

The pattern was there in the very first hospitals that noticed the outbreak, *before* epidemiologists even started looking for cases. And this means that in all likelihood the pandemic started at the market.

What about idea that the preponderance of early cases there was "just" a result of a superspreading event?

There are thousands of more likely spots/events for an early cluster of cases in a city of 11 million people: nursing homes, concerts, bars, theaters, shopping malls etc.

More importantly, the evidence of cases within the market in The Who report shows a *gradual" spread over weeks. Not an explosive event consistent with a superspreading event.

Also: Cases that had no epidemiological link to the market (didn’t work there or visit) nonetheless are concentrated heavily around the market. This is a clear signature that community transmission started at or very near the market, and only later spread widely around Wuhan.

Also: The man that is currently believed to be the earliest case, with Dec 8 onset of symptoms, actually had symptoms start on Dec 16. This dramatically changes the picture put forward by the joint China-WHO study report...

...which focused on this case being the earliest and him having no link to Huanan Market. The earliest known case is now a female vendor from Huanan Market. The Dec 8 case has been used by lab leak proponents to argue that the virus could not have emerged at the market...

...since the earliest case had no exposure there. It has led claims that the pandemic started at the BSL4 facility of the Wuhan Institute of Virology, since it is near where this guy lived and shopped. Turns out he just had a dental problem on Dec 8.

This “Dec 8” case, I am confident, has also loomed large in Biden’s 90 intelligence community review, leading one agency (FBI) to actually FAVOR the lab leak idea, and the others to have only low confidence in a natural origin. I anticipate updated assessments by the IC.

There was a tragic failure of China’s much touted Pneumonia of Unknown Etiology (PUE) system, where doctors are supposed to report cases of unexplained pneumonia rapidly (I believe within hours) to national authorities through an internet-based platform.

It failed, yet Chinese scientists involved in the program have claimed that’s how the outbreak was discovered. Not true. The true story is in my article, along with details of just how deficient reporting through this system was prior to the outbreak.

I also pinpoint the home location of patient with the earliest lineage A SARS-CoV-2 genome. It is just south of Huanan Market, and the family shopped just north.

The next earliest lineage A genome comes from a patient who had stayed at a hotel near Huanan just prior symptoms

I want to note that my article does not cover every important detail, not by a long shot. For example:

https://twitter.com/zhihuachen/status/1461506641531228163