1. Direct-jump from bat population
2. Started in bats, came to humans through intermediate animal
3. Came from frozen food outside of China
4. Lab accident.
I used to think the lab accident theory was crazy, because it sounds like a science fiction movie. Not an impossible theory, just a crazy one.
But according to this article, despite a year of investigation, (1) is unlikely because we haven't found anyone that interacted with the nearest bat population hundred of miles away that didn't work in the virus lab in Wuhan and that caught the virus, (2) is unlikely because we would have found the intermediate animal by now, (3) is unlikely because the first case found was in China (and not somewhere else... if frozen food had the virus, the food would have had it before it was frozen, and someone else would have had it), and (4) is unlikely because a government famous for blocking information and is paranoid about how it is perceived domestically and internationally says "No, trust us on this one."
At some point, crazy theories become the most likely. Hopefully I'm wrong though, and they find an explanation that isn't "lab accident." It seems like we should be studying viruses and sharing that information with each other, and accidents like this will make it more likely that such research doesn't happen.
2) is also likely, for some viruses it took years and years, sometimes even more than a decade to find the actual intermediate animal.
4) is unlikely because further analysis cannot produce a likely scenario. If the virus was from an animal source known to the lab, we would know already, and if it was due to a gain-of-function experiment, it would be quite unlikely for the virus to take so much time to adapt to humans (it still hasn't fully done so), and there is still a lot of function to be gained. Besides, there is no obvious marker for genetic engineering (the furin cleavage sites are perfectly well described by both 1 and 2), and the fact the virus does not seem to be at a local optima yet indicates that it's probably not the result of engineering by repeated selection.
Unless they started commanding to destroy samples, and sharing sequences of captured bats after the pandemic started.
> it would be quite unlikely for the virus to take so much time to adapt to humans
All experts agree that SARS-COV-2 is extremely adapted to human infection. Like it appeared out of nowhere, not the gradual result of a natural spill-over. To pose: "It could have been even more infectious" as an argument against gain-of-function is not very strong. And if we agree that China did not deliberately release a finished product, it would be weird to see optimal adaptivity.
> there is no obvious marker for genetic engineering
Gain-of-function does not create obvious marker. It is known possible to increase GoF of coronavirus using techniques that produce no markers at all. It is also tying it too closely to engineered bioweapons (vanilla SARS-COV is a bioweapon itself, even if collected from civet cats by terrorists), because the lab leak could also have been from a collected sample and accidental escape. There is no genetic engineering there at all.
The pandemic started months after first escape, and the WIV shares research findings internationally. By the time the pandemic was detected, it was way too late to destroy samples, months already went by. And that's assuming the escape happened as soon as the samples reached the WIV, which is very generous.
>All experts agree that SARS-COV-2 is extremely adapted to human infection. Like it appeared out of nowhere, not the gradual result of a natural spill-over. To pose: "It could have been even more infectious" as an argument against gain-of-function is not very strong. And if we agree that China did not deliberately release a finished product, it would be weird to see optimal adaptivity.
It is now, but it wasn't at first zoonosis. It took months for the virus to ramp up to an epidemic, whereas clearly the current iteration of the virus can do so much faster especially in dirty environments. Besides, the virus is still, one year in, nowhere near maximum adaptivity, with significantly more infectious variants still appearing. It's not that it could have been more infectious, is that it now is significantly more infections. As far as "deliberately releasing a finished product", there is no reason for it to matter - the last iteration of a given strain will be subject to experimentation for a long time.
Moreso, SARS-CoV-2 clearly has an insanely high potential for zoonosis, as we've seen it infect an incredibly large cross section of animals. This is not what you would expect from a virus that previously was only ever in one species and that was engineered to be specifically adapted to humans only.
>Gain-of-function does not create obvious marker. It is known possible to increase GoF of coronavirus using techniques that produce no markers at all. It is also tying it too closely to engineered bioweapons (vanilla SARS-COV is a bioweapon itself, even if collected from civet cats by terrorists), because the lab leak could also have been from a collected sample and accidental escape. There is no genetic engineering there at all.
You're stretching the definition of bioweapon way beyond any reasonable definition. Both SARS-CoV and SARS-CoV-2 make really poor bioweapons, many naturally occuring viruses are far superior. If the lab leak was from a collected sample that accidentally escaped, you would again expect it to be of known origin - China could point to a specific source and say "Hey, we found it, it comes from here!", and likely collaborators would know about it. Additonally, if it came from GoF, you would expect it to find and expend single-base-pair mutations with a high impact on pathogenicity already, yet we still had many crop up.
Often heard this, including from experts in bioscience (I am not one, you sound more like it).
So early on I did a search on Google Scholar for things like: SARS bioweapon to see what I could come up with. Turns out there is a lot of biosecurity and biowarfare literature from before the outbreak, which have entire chapters for SARS coronavirus as a weapon.
I really think if you tried to give some reasons for coronavirus being a poor bioweapon, it would expose either an inflated sense of expertise, or those reasons are precisely the reason coronaviruses are seen as attractive (and relatively cheaply available) bioweapon.
In a: don't do what I say, do what I do-manner: US military is warned not to use DNA tests from companies that offer cheap tests due to Chinese government funding. It may leave them open to "identification" and "attack". How poor would a gene-targeted coronavirus actually be?
The rest of your posts seems to gather support for other hypothesis, not as much attacking the lab leak theory as highly unlikely.
There is biosecurity and biowarfare literature on pretty much every single virus you can imagine - generally it's about how it might be modified to be used as a bioweapon. And really, coronaviruses are quite good platforms for making debilitating airborne weapons.
SARS-CoV itself as a bioweapon is simply not infectious enough, it was sucessfully contained dozens of times. It's also not that lethal to military-age men, for 20-29 year olds CFR is around 1% and for 30-39 year olds it's around 3% (taking data from infections in the PRC and in HK as there is the least low-detection bias). But it definitely has a lot of potential if you engineer it. For reference, the average age of a soldier in WW2 was 26.
SARS-CoV-2 is complete trash as a bioweapon, an entire carrier was infected and no one died. Debilitation was minimal. It's infectious enough, but it's very bad at actually killing military aged people.
But certainly, they could be engineered to be suitable. That's not the claim I was replying to - the claim I was replying to was that in it's natural form it was a bioweapon.
>The rest of your posts seems to gather support for other hypothesis, not as much attacking the lab leak theory as highly unlikely.
Likelihoods are relative. Everyone agrees that likelihood for a lab escape is fairly low - those are relatively rare. The argument is that the normal process for viruses to reach humans - which was the case for literally every single other pandemic ever - is unlikely thus making lab escape more likely relatively.
I did, however, add a few points that go against the likelihood of an undetected lab escape - which is that the existence of the sample would almost certaintly be known.
No known treatment or vaccine. Targets the decision makers (presidents and ministers and military generals are older, and a virus is easier to reach them, than a bullet is). SARS-CoV has super-spreader events, and asymptomatic spread, making it very difficult to contain. It spreads incredibly easily (near-airborne), in confined spaces such as airplanes, but even the toilet plumbing, or shared airco. It offers plausible deniability, by pointing to a natural spill-over event or unsanitary meat markets. It causes enormous economic damage (the economy, not the cannon fodder, being the subject of modern warfare) and cultural damage (tracking and containment is costly and invasive as it damages trust in a free society). It is most readily available to small states and terrorist groups by extracting from live civet cats. Military-aged terrorists spreading SARS-CoV by simply boarding airplanes and visiting hot spots, and not even dying themselves, so they can do it all over again. SARS-CoV in first stages has vague symptoms, similar to other, more common viruses, which would give a pandemic a head start. Pandemics are good PR for fear-based terrorism. The strain on the hospitals is enormous, and military-aged men are too worried to reserve a bed for their elderly parents or their recovery.
More in the vast literature.
> SARS-CoV-2 is complete trash as a bioweapon.
If complete trash, I would not be afraid of Iran being able to press a button and release SARS-CoV-3 for a 2020 repeat. Even if looking at viral bioweapons from the comical anthrax perspective: SARS-CoV-2 killed over 2 million people.
> that the existence of the sample would almost certaintly be known.
Yes. It would make sense that it would be known. And if it would be known, that would probably sufficiently proof the lab leak hypothesis and end this quarrel. We wouldn't need to talk about probabilities much anymore. But that same argument kinda also works against the zoonotic origin hypothesis. It would make a lot of sense that after a year, we found the intermediate host, or patient 0. If there was a clear epidemiological explanation for a zoonotic origin, it would almost certainly be known. Maybe there really isn't.
Not true - there are basically known vaccines to SARS-CoV, they just never got to human efficacy trials because the disease went extinct. But, given their efficacy when repurposed as SARS-CoV-2 vaccines, they were probably quite effective.
As for super-spreading events, this is a double edged sword. It makes it very infectious when nothing is being done to try and stop it, but it means that if there are even cursory measures the chances of the infection stalling are much higher as you're relying on a low number of people actually spreading it.
SARS-CoV may have vague symptoms in the early stages - but it has symptoms. You want a virus that can spread asymptomatically for it to be a major burden, so that makes it less useful.
If your goal is to strain hospitals and create fear, by far the best tools would be humanized avian flu, or a vaccine resistant strain of measles.
>Yes. It would make sense that it would be known. And if it would be known, that would probably sufficiently proof the lab leak hypothesis and end this quarrel. We wouldn't need to talk about probabilities much anymore. But that same argument kinda also works against the zoonotic origin hypothesis. It would make a lot of sense that after a year, we found the intermediate host, or patient 0. If there was a clear epidemiological explanation for a zoonotic origin, it would almost certainly be known. Maybe there really isn't.
I think you're missing the point. If there was a lab escape, the likelihood for the sample to be known is very high. This means that given priors of no known samples, the likelihood for a lab escape is lower.
It's also completely unrealistic to expect to find the host or patient zero after a year for a zoonosis. It took 40 years to find the intermediate host for Ebola, and four years to find it for SARS. For some epidemics, we never found a solid intermediate host. Patient zeros are basically never found, either, unless the disease is incredibly pathogenic and virulent - which SARS-CoV-2 isn't. If you look towards past epidemics that originated from zoonosis with a similar disease profile, you will find that it takes years to decades to conclusively find an intermediate host, and that patient zero is basically never found with any degree of certainty, meaning that the current scenario is perfectly congruent with expectations.