[opendoor]

Originally Posted by jjgallow

We're talking about one of the most contagious multi-species viruses ever, so, yes, but, also not needed.

I would assume most likey that there was one initial escape from the lab. Now, we're giving the lab possibly more credit than they deserve in assuming that.

What happens after that, however, is inherently random and we can actually expect to see multiple transmission paths and lineages.

All the humans who worked at the lab also had close contact with mice, bats, etc. As did surrounding residents with at least mice.

So it could have gone:

Human->mouse->human->bat->mouse->Human

Bat->human->mouse->bat->human

Mouse->human-farm animal->mouse->bat->farm animal at the market->human

Or about 10000 other combinations.

None of which rule out the lab in any way or explain away the clear splices seen in the virus .

So on the one hand it's one of the most contagious multi-species viruses ever in existence. But at the same time you think it transmitted undetected in humans long enough to go to and from a bunch of animal reservoirs, remained transmitting in the animal populations long enough to develop the different lineages (without infecting basically any humans), and then jumped back into humans where it took off quickly. That doesn't seem very plausible given the growth rates we've seen in immunologically naive human populations.

And it's also at odds with basically every lab leak hypothesis I've seen. The primary foundation of most of the lab leak hypotheses is that there is zero evidence (or even plausibility) that SARS-CoV-2 spread in humans undetected for a period of time. Their whole argument is that it came out of nowhere via a lab leak, which is why it went from nothing to a pandemic in a few weeks. That doesn't really fit with the idea that it spread around in humans and animals around Wuhan long enough to generate the genetic diversity that existed.

I honestly never heard of a human-only theory. I believe you that there surely was one but can't have been well thought out.

That's basically the only legitimate and plausible theory of the lab leak. The theory is that a worker (or workers) at the lab unknowingly became infected with a coronavirus they were working on and/or that animals in the lab had been infected with. Some posit that it was a virus that an animal came into the lab infected with (the same idea as the bat virus that killed those miners in 2012), while others suggest that it was the result of gain of function research. Either way, the worker(s) would have then spread it outside the lab and it took off quickly from there.