[samatman]

Well, it lowers your chance of being listed as an infected person.

Presuming this is true (lots of evidence but still much too early to be sure), there's two possibilities: nicotine makes a person less likely to be infected, or nicotine makes it less likely that the infected will develop any symptoms. No symptoms, no test, that's been the rule until quite recently.

If it's the latter, it could explain what's going on here. I doubt that's the explanation, but it's possible.

[_2d30]

There seems to be a reasonable path to effect regarding regulation of ACE2 which is the primary receptor molecule for COVID.

https://www.qeios.com/read/article/571

[hkeide]

A couple more possibilities could be that smokers are less likely to notice any symptoms they might have, or are less likely to report those symptoms and get a test. Smokers are probably less conscientious on average - it's almost the definition of lack of conscientiousness.