Thread by @angie_rasmussen

So...the DOE decided that SARS-CoV-2 originated with a "lab leak."

The available evidence shows overwhelmingly that the pandemic started at Huanan market via zoonosis.

But affirmative evidence of lab origin could change my view. What kind of evidence? 🧵
nytimes.com/2023/02/26/us/…

First of all, I have no idea what this evidence that DOE has is. All I know that it is "weak" and resulted in a conclusion of "low confidence". It reportedly comes from the DOE's own network of national labs rather than through spying.

But I do know that to be consistent with the available scientific evidence, the DOE has to explain how the virus emerged twice over 2 wks in humans at the same market the size of a tennis court, over 8 km & across a river from the only lab in Wuhan working on SARSr-CoVs.

For more on that you can see my thread on what my co-authors and I showed. By the way, today is the year anniversary from when we dropped these preprints (eventually published in @ScienceMagazine). No challenge to our work has yet survived peer review.

https://twitter.com/angie_rasmussen/status/1551937826580824070?s=20

But that said, I'm always prepared for the possibility that new evidence can falsify a hypothesis. No hypothesis is too precious for evidence to trash.

One piece of evidence that could change my mind would be conclusive proof that WIV possessed a progenitor of SARS-CoV-2.

We don't have pandemics all the time, despite spillover being pretty common, because most spillovers are dead ends with no onward human transmission.

Pandemic-ready viruses are themselves exceedingly rare. Emergence in a situation that allows a pandemic to start is rarer still.

If WIV was doing experiments with a virus that could have evolved into SARS-CoV-2, that would dramatically change the likelihood that this virus would coincidentally emerge somewhere in Wuhan naturally, especially if it was collected years earlier in a far-off location.

Indeed, many lab leak proponents have floated a myriad versions of this possibility. We're always just a random out-of-context FOIA email or one deleted database away from uncovering THE TRUTH about what *really* happened in Wuhan.

So if this is the kind of evidence that would change my mind, why do I still think the pandemic started with zoonosis at or immediately upstream from Huanan market?

Simple. This evidence doesn't exist. Claims of a progenitor at WIV are pure speculation & unsupported by evidence.

Viruses aren't imagined or computed into existence. No serial passage, gain-of-function, humanized (transgenic) mouse studies or whatever else has been proposed to be the laboratory origin of SARS2 can happen without a progenitor.

And ZERO evidence suggests WIV had one.

No progenitor virus = no reverse genetics or isolation
No reverse genetics or isolation = no virus in culture
No virus in culture = no infectious virus at all

No infectious virus = no lab leak.

Despite 3 years of a global search for this evidence, it has not materialized, while evidence supporting zoonosis associated with Huanan has continued to stack up.

At some point, an absence of evidence might just be evidence of absence.

As I said before, I am willing to reconsider my hypothesis if presented with verifiable, affirmative evidence of a progenitor virus at WIV.

I don't know what the new evidence is, but if it was obtained from the DOE's labs, I doubt it will point to a WIV progenitor.

I'll keep an open mind when and if we ever get more information about what has caused the DOE to change their assessment (as well as toward other emerging evidence about the origin of SARS-CoV-2).

But for now, I see no evidence that suggests the current scientific evidence base is incorrect. And that evidence base continues to suggest the pandemic originated via zoonotic spillover at the Huanan market, in association with the live animal trade.

And this is an important addendum.

https://twitter.com/flodebarre/status/1629936622354432000?s=20