During the Spanish flu of 1918-19 smoking was promoted as a way to stave off the flu.
Many years ago, I worked with a gentleman originally from Prussia. When he was a little boy, he and his mother were among those escaping as the Russians moved in.
In the midst of all of this, he contracted a bad cold or flu that affected his lungs, and his mom gave him cigarettes to smoke.
Apparently, some of the old folks thought it had some benefit.