a thing they mostly don't tell you in education school is that for your first year or two you are going to be sick.
very, very sick.
you are going to get more colds and stomach bugs than you thought were possible. many of you will go for eight or nine months without having a solid bowel movement.
you, new teacher, are about to enter an environment where all the germs in the world are going to pass through your classroom, and if you teach in an elementary school the sheer volume of pathogens that get dribbled out onto every surface will boggle your mind.
if you are a classroom teacher, you will be VERY heavily exposed to all the germs of the kids in your class, but if you are the music or art or gym teacher you will get light exposures to EVERY GERM IN THE SCHOOL.
at some point, maybe year four or five, you mostly stop getting sick. you only maybe get one cold a year, but the one you get is the epic one.
you develop such a resiliency over time that when the administrative assistant comes around to your classroom to take a survey on how many faculty will be calling in sick tomorrow because THAT many kids and teachers are down with this year's flu, you think quietly that tomorrow you will do your grocery shopping and maybe take yourself out to lunch.
you are so immune to everything that you do not hesitate to eat stuff you find on the floor.
in a rest area parking lot.
and then you retire.
and after a few years you maybe realize that your super immunity is gone because you live alone in the country and when you see live people it's usually outdoors or in sporting venues where sick people usually aren't. you don't get any colds, because you're not exposed to any germs.
so you go a number of years without being exposed to a barrage of viruses and all of sudden one day you realize that you have no resistance to anything anymore and on average you're going to be sick about five days for every time you spend more than an hour in a closed room with people.
if it is flu season, you just simply stop talking to people in person.