In the early days the data was fairly clear. We have a new virus which could be of natural origin or lab origin, but the early spread data basically showed two different strains at first jump to humans, suggesting a fairly large number of infected animals in the same area around Wuhan. This is much more consistent with a natural spillover than a lab leak because the differences would take time to accumulate. If you have a virus in a new host it adapts to that host rapidly and changes, so if two separate animals of different species were both infected that would make two different strains with two different spillovers into humans and it happening at almost the same time is not crazy, both animals may have been in the same place and gotten infected at similar times.

If it were a lab origin it would be identical virus when it jumped over to humans. It would also have been better adapted to humans and not had as much change in humans in the first few months.

So is it possible it was a lab leak? Yes. Is it more likely than a natural spillover? No, not more likely. Possible, but no specific evidence that makes it reasonable to conclude either than we know for sure what happened or that it was a lab leak. The correct answer here is we don’t know for sure now but regardless of what happened this time we know another event will happen in time and natural spillovers are just as dangerous as lab leaks. We need to have a One Health approach, taking care of humans and also the natural environment and the interplay between them. Having humans living on the edge of wild areas is a recipe for disaster.

Wasn’t the consensus of virologists in the early days of the pandemic that a lab origin was completely preposterous?

I’m never going to buy that the virus randomly naturally popped up a few miles from a huge research lab that happened to be studying it too. Money is on someone inadvertently carried it out/got sick.

Edit: this is not meant as anti China. Accidents happen

Now researchers are presenting an analysis in the journal “Risk Analysis” in which they examined the likelihood of an unnatural origin for the virus in a laboratory. They come to the conclusion that such a phenomenon could be more likely than a natural one.