[anonuser123456]

Another missing piece to the puzzle is the impact of smoking and air pollution.

Wuhan is particularly intertesting in that 50% of males smoke. Additionally, the air is terribly polluted. We know from ordinary flu, both of those factors increase mortality significantly. More interestingly, it looks like smoking may increase ACE2 expression and make people more succeptable to the virus.

So there could be environmental factors endogenous to the region that may not hold globally that drive both infection rates and disease severity.