This doesn't directly address smokers and the Spanish Flu although it makes the point. For some reason, I can't find a quick link to that although I've been reading about it for years and have been planning on using nicotine to suppress the cytokine storm response if I get CoViD. Even though this piece is talking more generally, the Spanish Flu and nicotine's effect on cytokine storm is mostly what I was looking for.

[link to www.ncbi.nlm.nih.gov (secure)]

For example, the H1N1 strain that caused the 1918 pandemic has been shown to induce higher levels of proinflammatory immune cells and cytokines in the lungs than seasonal influenza viruses. This contributes to its high virulence and may account for the unusually high mortality rate seen in otherwise healthy young adults during the outbreak

Nicotine is a nonselective agonist of the α7Ach receptor and is able to suppress the production of proinflammatory cytokines by mimicking the binding of acetylcholine. It has been demonstrated that nicotine can selectively reduce the inflammatory response in a number of infection scenarios, including Legionella pneumophila (54) and Chlamydia pneumoniae (55) infection; however, it is highly unlikely that nicotine will ever be used clinically due to its toxicity, addictive nature, and lack of specificity.