Lindsay Beyerstein has a very through piece arguing that while the lab leak origin story for COVID-19 is possible, it’s also not very plausible and there’s no serious evidence for it:
What we’re left with is this: If the WIV had a secret strain (or strains) at least 99 percent similar to Covid-19, it got that raw material from the wild. That would mean there’s at least one wild virus that’s at least 99 percent similar to Covid-19 somewhere in nature, where humans had contact with it at least once. So far, it hasn’t been found, but it’s got to be out there, whether Covid is 100 percent natural or human-tweaked. So, given that Covid (or its direct ancestor) must exist in nature, it’s more likely that it got out naturally (like SARS and MERS) than that it took an undetectable detour through a secure biolab.
If Covid-19 were bioengineered, that would mean the WIV lab found the now-untraceable Covid-19 precursor strain(s), and even though its main job is publishing about the cool viruses it finds, it never published it or talked about it, not even to the small army of American and international scientists it collaborates with. Then it embarked on a painstaking process of undetectably tweaking the Secret Ancestor into Covid-19, its manipulation succeeded, and then multiple layers of biosecurity failed, and Covid-19 escaped.
It’s not impossible. But it involves a number of exceptions to rules—a number of carefully designed systems failing. Meanwhile, the natural origin theory just involves countless bat roosts with millions of bats doing what they do best: generating new viruses like the world’s most chaotic supercomputer.
All theories of the origins of Covid-19 should be investigated, including lab origin theories. We should go wherever the science takes us. In mid-May, 18 respected scientists with relevant expertise published an open letter in the journal Science arguing that both zoonotic and laboratory origin hypotheses “remain viable.” This letter was seized upon as additional grounds to support the lab leak theory, seemingly by people who hadn’t read it very carefully. The authors didn’t offer any new evidence, or even an argument, for why the lab leak theory deserves to be taken more seriously. Their focus was criticizing China’s stranglehold over the raw data on the origins of the pandemic and calling for a more transparent investigation.
These are entirely valid criticisms, but on their own, they don’t move the needle on the likelihood of a lab leak. The fact that China is being secretive about Covid-19 isn’t evidence for any particular theory. China is a totalitarian regime that is notoriously secretive about everything. It should be noted that the origins of both SARS and MERS were shrouded in troubling official secrecy before they were confirmed to be natural phenomena.
I recommend the whole thing. The sudden obsession with lab leak theory seems like Making #Slatepitches Great Again to me.