My Mom was a school teacher and every year at the end of school she would find out what kids had what .. chicken pox etc . and she would send us over to play so we would get these assorted germs in the summer and not during the school year. That way neither her or us would miss a day of school. Back "then" it was the only method of management, in other words , you knew your kids were most likely going to get it .. it was just a matter of when.
An issue facing all of us in the land of germ paranioa is that all the germicides are actually keeping us from developing strong immune systems. In order for your body to develope a strong immune system it has to be exposed to germs!