Can farts spread disease? That's the question Mental Floss poses, and after having looked at a small bit of science, their conclusion: "If you're wearing pants, you should be fine." Actually, even if you are butt naked you should be fine, unless, perhaps, you're within five centimeters of another human.
Searching for an answer, Mental Floss dug up a 2014 Discovery article that describes an experiment that involved farts in petri dishes. As described by science author Karl Kruszelnicki on Discovery:
"I contacted Luke Tennent, a microbiologist in Canberra, and together we devised an experiment. He asked a colleague to break wind directly onto two Petri dishes from a distance of 5 centimetres, first fully clothed, then with his trousers down. Then he observed what happened. Overnight, the second Petri dish sprouted visible lumps of two types of bacteria that are usually found only in the gut and on the skin. But the flatus which had passed through clothing caused no bacteria to sprout, which suggests that clothing acts as a filter.
Our deduction is that the enteric zone in the second Petri dish was caused by the flatus itself, and the splatter ring around that was caused by the sheer velocity of the fart, which blew skin bacteria from the cheeks and blasted it onto the dish. It seems, therefore, that flatus can cause infection if the emitter is naked, but not if he or she is clothed…"
Cut to 2020 and the coronavirus, and Mental Floss says: "Earlier this year, a Beijing district office for the Center for Disease Control and Prevention announced that pants should be an effective barrier against farts that might carry the novel coronavirus. So to avoid spreading COVID-19, practice responsible social distancing—and avoid farting naked around other people."
Uh, yeah. Good advice, pandemic or not!