I think @HoneyBadgerDC may be asking a question which has also been bubbling away at the back of my mind. Without trawling for cites, the received wisdom seems to be that there is, loosely speaking, a threshold amount of virus required to cause infection/disease. Typically twenty minutes in close proximity with an infected person, or something like that (don’t hold me to twenty minutes!)
But what about just a few virions here and there, say - a few seconds contact as you pass someone on the sidewalk - they are infected but not coughing; you are exposed but very slightly. I’m sure I’ve heard (UK) government advisors say something like, that’s not a problem, your body can cope with that. And I guess these sorts of minimal exposures may be frequent, at least in urban environments.
OK, if that is the case, what’s going on? Is your immune system coping with this minimal exposure in some way? If so, is this repeated exposure to a few virions here and there sufficient to produce a level of immunity? Is your body “coping with” this exposure in a different way? What, if anything, do we know about this?
(And my apologies, @HoneyBadgerDC, if I have misrepresented your OP).
j