Tobacco smoke is a source of niacin (aka nicotinic acid). It was known by July 2020 that people who smoked were by and large protected from "COVID", either not getting it at all or getting a milder than usual case.
Correct. Posting the below got the attention of Twitter back in the day.
French researchers to test nicotine patches on coronavirus patients
https://www.theguardian.com/world/2020/apr/22/french-study-suggests-smokers-at-lower-risk-of-getting-coronavirus?CMP=share_btn_fb
The consistent low rate of #tobacco smokers among patients with #coronavirus in China is now duplicated in the U.S. by CDC:
Among 7,162 corona patients with medical records 6,901 were never-smokers (96.3%), 165 ex-smokers (2.3%), and only 96 smokers (1.3%)
https://www.cdc.gov/mmwr/volumes/69/wr/mm6913e2.htm