I believe that is the case for covid at least. If you don't get as sick then that means the virus didn't manage to spread inside the body as much, so there is l

I believe that is the case for covid at least. If you don't get as sick then that means the virus didn't manage to spread inside the body as much, so there is less viral material that can be spread to others. Now I'm not saying this relationship is linear, I have no clue. We'd have to ask an actual expert. You are right that this could be offset because there is no isolation happening in case of an unknown infection.