[jfoster]

Suppose you're right about reasons why it spreads fast & lethally in China. How do you explain the fast spread and lethality outside China?

[Enginerrrd]

The two "fast"'s are relative. Epidemic dynamics are likely to differ in different countries for a bunch of reasons.

And, it does appear to be less lethal outside of China. That may be because healthcare systems are not yet overwhelmed, or it may be because of the smoking and pollution exposure in the different demographics. It is probably even both of those things.

[zaroth]

The latest numbers from the WHO say that although CFR was much higher in January, a new case in China in March will have a CFR of 0.7%.

They are guessing this shift could be due to a combination of reduced transmission load and refining treatment protocols.