[tripletao]

Take a look at this on a map. Mojiang (where RaTG13, the closest known relative to SARS-CoV-2, was reportedly sampled) is closer to Chongqing, Chengdu, Guangzhou, Shenzhen, or HK than to Wuhan. Pu'er is roughly Chicago-sized, and it's 150 km away. Kunming is more people than two Chicagos, and it's 200 km away. It makes sense that this first emerged in a city, but Wuhan is far from the obvious geographic choice.

[koheripbal]

Maybe folks in Mojiand have some immunity because other variants spread there before? Maybe that's why Vietnam (cause Hanoi is close too) have been largely spared. Maybe Wuhan has a bigger market for "wild meat" than rural places - that wouldn't surprise me. Maybe RaTG13 is present in a lot of places. Maybe there are some even closer relatives to sars-cov-2 closer to Wuhan.

Again, none of this is conclusive. It's all speculation. maybe maybe maybe. There are lots of potential ways for this to have happened natually.

[tripletao]

FWIW, I do suspect cross-immunity will eventually explain a lot of mysteries of this virus, including why the Asia-Pacific region has been so lightly-hit compared to Europe and the Americas. So I do agree it's possible that weaker population immunity in more distant regions more than offsets less frequent spillover, and paradoxically makes them the more likely regions for an outbreak (although that's not what experts including Zhengli Shi had originally guessed).

But there's lots of other distant cities in China too, and none of them have virology institutes with the world's biggest collection of novel SARS-like viruses. So whatever your prior was for lab accident vs. natural, I do believe the location in Wuhan should significantly increase that. Certainly far from conclusive, but a possibility that requires serious investigation.