Thread by @gdemaneuf

@BiophysicsFL @stuartjdneil @Ayjchan @TheSeeker268 @R_H_Ebright @breakfast_dogs The BSL-4 was not studying BatCoVs, this was instead done in various institutions at BSL-2 and BSL-3, so the location argument - while being essentially correct - is a bit misleading.

@BiophysicsFL @stuartjdneil @Ayjchan @TheSeeker268 @R_H_Ebright @breakfast_dogs Also the historical argument which considers a zoonosis 1000x more probable (a priori) than a lab leak is incorrect.

It’s only over the last 15 years that BatCoVs have been extensively studied, and there were 6 primary cases of LAIs including one with community outbreak.

@BiophysicsFL @stuartjdneil @Ayjchan @TheSeeker268 @R_H_Ebright @breakfast_dogs Not counting that outbreak because it was not a pandemic is based on another wrong generalisation: it’s only during the last few years that China was looking at enhanced pathogenicity of BatCoVs at scale using passaging or by building chimeras (you can date that to 2017).

@BiophysicsFL @stuartjdneil @Ayjchan @TheSeeker268 @R_H_Ebright @breakfast_dogs And it is only since 2018 that it is has targeted the FCS in particular.

Working on a BatCoV with FCS totally changed the probability of pandemics in a quadratic way:
It increases BOTH the probability of lab escape AND the probability of pandemic given a lab escape.

@BiophysicsFL @stuartjdneil @Ayjchan @TheSeeker268 @R_H_Ebright @breakfast_dogs Hence any calibration based on historical data is totally off by a huge factor.

Going back the the SARS lab escapes of 2003-04, if the pathogen was SARS2 at the time, you would likely have seen more than 6 LAIs, and likely more than one would have ended up on an outbreak which…

@BiophysicsFL @stuartjdneil @Ayjchan @TheSeeker268 @R_H_Ebright @breakfast_dogs would have been much more likely of ending in a pandemic (partly also due to the fact that SARS2 has a large asymptomatic rate and a longer infectious period before the symptoms break out).

SARS-2 is a totally different game.

@BiophysicsFL @stuartjdneil @Ayjchan @TheSeeker268 @R_H_Ebright @breakfast_dogs Now there is no similar structural change in nature. Yes there may have been more human pressure, but at the same time deforestation has been partly reversed and so many of these villager close to bats - especially in Yunnan- have been depopulated and are now full of oldies.

@BiophysicsFL @stuartjdneil @Ayjchan @TheSeeker268 @R_H_Ebright @breakfast_dogs Yes, there has been more wildlife farming in recent years too. But that also came after some pull back following SARS.
In any case all these factors are smaller and linear, not quadratic.

@BiophysicsFL @stuartjdneil @Ayjchan @TheSeeker268 @R_H_Ebright @breakfast_dogs @threadreaderapp compile