A few of many related research papers and articles I found very interesting in the early days of C19:
“Daily active smokers are infrequent among outpatients or hospitalized patients with COVID-19. Several arguments suggest that nicotine is responsible for this protective effect via the nicotinic acetylcholine receptor (nAChR). Nicotine may inhibit the penetration and spread of the virus and have a prophylactic effect in COVID-19 infection.”
https://clinicaltrials.gov/ct2/show/NCT04583410“A French study suggests that smokers could be less at risk of catching the coronavirus — and researchers now want to test nicotine patches on patients and health care workers ... probing whether the nicotine in cigarettes specifically plays a part in stopping smokers from catching the illness ... researchers found that the number of smokers among their patients was much lower than that in the general French population. ‘Our cross-sectional study strongly suggests that those who smoke every day are much less likely to develop a symptomatic or severe infection with Sars-CoV-2 compared with the general population’ ... ‘The effect is significant. It divides the risk by five for ambulatory patients and by four for those admitted to hospital. We rarely see this in medicine’”
https://nypost.com/2020/04/22/french-researchers-to-test-nicotine-on-coronavirus-patients/“Leading Welsh doctors claim nicotine patches could offer hope of a possible treatment for coronavirus ... has the potential to block the virus from entering cells ... ‘The idea behind the French research is that Covid-19 is understood to attach itself to the walls of cell receptors [known as ACE 2 receptors] in the upper aiways. The virus then acts like a key to unlock the cell, allowing it to enter it and then use its infrastructure to multiply’ ... ‘While nicotine is also able to attach itself to these receptors and act as a key to unlock the cell, it doesn't actually enter’ ... ‘The French team postulate that instead, it acts as a barrier to the virus accessing the cell - as the key is already in the lock, so to speak.’”
https://www.walesonline.co.uk/news/health/welsh-doctors-claim-nicotine-patches-18162229
