I would think diseases adapt via an evolutionary like process. If people who display visible symptoms spend less time interacting with others (stay home from school, don’t go to parties, take sick leave), then there’s selective pressure to have less symptoms. Either those symptoms aid in transmission, or there isn’t any standing variation in coughing / sneezing severity which seems unlikely.
I would think diseases adapt via an evolutionary like process. If people who display visible symptoms spend less time interacting with others (stay home from school, don’t go to parties, take sick leave), then there’s selective pressure to have less symptoms. Either those symptoms aid in transmission, or there isn’t any standing variation in coughing / sneezing severity which seems unlikely.