[cskinner]

Nicotine (smoking) has been known to act as an immunomodulator and can act as a preventative for gastrointestinal inflammatory disease such as ulcerative colitis. This could be attenuating the inflammatory response and reducing symptoms for COVID-19 patients.

https://www.medscape.com/viewarticle/516104_4

[rapjr9]

The additives in cigarettes have been shown to dilate lung airways, suppress coughing, and disguise symptoms of illness:

https://www.verywellmind.com/cigarette-additives-2824737

Perhaps the additives are keeping COVID-19 patients alive by supporting breathing in difficult circumstances? There are hundreds of additives so figuring out if any of them help would be difficult:

https://ec.europa.eu/health/scientific_committees/emerging/d...