It's a little thing, but made a small improvement to the status quo. I play table tennis. I suggested installing hepa filters to try to mitigate virus transmission to my club, who laughed at me. Months later, I created my own club and God damn it, we do indeed have hepa filters! Between that and using the Norizite nasal spray, I've made it through winter without even a cold. Not solid evidence I know, but the odds of that happening when I'm seeing 30 odd people 3 times a week are pretty slim I would think.