Many work places give limited amounts of sick days, and some require Dr’s notes when they are taken. how many people run to their Dr when they have a cold, or even the flu? This policy, supposedly to make sure that people only take off when they are truly sick, and avoid excessive absences, can back-fire, since it means that people are forced to go to work when they are sick, only to infect others and reduce productivity all around.
In any case, you can’t force people to stay home, there will always be viruses and germs lurking in our environments- on the door handles of your classroom, or public bathrooms, the buses and subways, on the money you get from the cashier, etc. B”H our immune systems are kept very busy. The immune-suppressed do have it hard, they often are confined since it is impossible to make our world sterile.