Has the origin ever been definitively decided? It seems that most scientists think it was zoonotic in nature, but there’s not full agreement or full clarity:
https://gcrinstitute.org/covid-origin/
Some US government agencies have different views on the likely origin, too.
Is this one of those questions where we’ll never get full clarity until China comes clean? It’s something that should eventually be fully settled within the science community.
There are conspiracy theories about the origin of COVID, but as you suggest, the majority of credible researchers believe it came from an infected wild animal slaughtered and sold in an outdoor Chinese market (a zoonotic event).
Will they ever prove beyond doubt that was the origin of COVID? That’s unlikely, although zoonotic events are certainly not unheard of. To prove it they would need to narrow down the potential virus-infected animals to see if they can find the COVID virus still living in the wild, but that’s an incredibly difficult thing to do.
If China is directly responsible for the development of the COVID virus, such as in a laboratory, I doubt we will ever know that, at least in our lifetime.
There’s not really any possibility of a non-zoonotic origin. The question, to the extent that there is one, is where and how the crossover to humans happened. The smart money is on an animal slaughtered and sold in a Chinese market, but it could also, for instance, have been a human in a rural area outside of the city of Wuhan coming in contact with a wild animal and catching it, and then that infected human coming into the city (maybe into that same meat market, so the spread from there would be identical). Even in the extremely implausible case that it was created in a lab, it would have been created from some existing animal coronavirus.
the big difference in proving one origin over the other is, in a lab, you’d expect there to be a lot of actual evidence. Research logs, samples in freezers, eyewitness accounts of the scientists involved. So we should demand at least some of that kind of evidence before thinking it came from a lab.
But an animal in the wild, or even hanging in a meat market? It was dinner and then trash weeks before the first infected person would have shown symptoms. It’s virtually impossible to provide positive evidence of that, and so we’ll never know for sure that this was the source.
so, lacking any actual evidence one way or the other, it’s safe to provisionally conclude it came from the animal, since that’s the explanation for which we’d expect there to be no evidence. Those who want to push for the lab-based explanation know what they need to do to support that - show us any of the evidence as listed above.
The evidence to date strongly favors spillover from the wild rather than lab leak/human construct theories, and most scientists with relevant training and experience support a natural origin.
Absolute certainty as to SARS-CoV-2’s origins is extremely unlikely to ever be attained.
It’s been over a year and I don’t have a link, but I read an analysis dissecting the “came from a lab” argument and discarding it as unlikely. The key point seemed to be an allele-by-allele comparison to older similar corona viruses, and saying "here, here, and here are several change sequences that COVID-19 contains that are likely making COVID-19 more contagious than older corona, and over here and here are some making it more lethal.
“If gene splicing were being done in a lab to weaponize older COVID, no one would have inserted this segment, it wasn’t known to have that effect, they would have most likely used [sequence] or some variety of [sequences]. Lab folks don’t just randomly insert some gene segments to see what might happen if they do. The ones I’ve discussed here are unlikely deliberate insertions, either we had no way of knowing they’d have that outcome result or [other reason having to do with stuff we know more about and would have been more likely to use in a lab]”.