The covid virus can't stand to be dried, or exposed to oxygen, and/or UVC light. That's pretty much the same for all viruses, they have various degrees of armor coat. They are happy in gobs of snot that you spit out into somebody's eyes. From the physics, I am sure that 90% of covid infections come from a loud-mouth moist speaker into the the other's eyes. Only one virus needs to make the trip.
It is much harder to pick up the virus through your nose, or touching a surface. But I address that through uvc air filters. I have converted two big air filters to uvc. Air filters are like printers, they are cheap, but the expendables are ridiculously expensive. I use sheets of electrostatic filter cloth from ammie as the filter, and I install a cheap compact uvc light from ammie.
You can improve the performance of the uvc light by having it shine on titanium oxide, or Titania. That's a great catalyst for donating electrons to break up globs and destroy critters. But these bulbs only really last a year. Technically it's longer, but the glass tubes get really dark. The only smell is a sense of fresh air. Don't get the bulbs that produce ozone. They are for smoky hotel rooms, and you have to get out, since ozone attacks the lungs.
Doing all this probably cuts down the chances of contagion by 5%, but I like the healthy feel of the place, like opening windows which you can't do during ragweed season. Have fun!