People who have the flu go to grocery stores and restaurants and cough all over. Nothing worse then working in an office next to the guy that coughs nonstop all over every surface. If people would just stay home (or keep their kids home) while contagious we could eliminate the flu altogether.
Viruses will always run their course and run rampant, there’s not a lot one can do about that. By all means, if you’re sick, stay home, but prior to even feeling sick, it was already passed on.