I suspect that a great deal of the sickness one sees i this profession is a direct result of LACK of exposure to various things. No, not just pathogens - that matters more when you're a kid. I'm thinking of things like sunlight!

A little common sense, the standard clean regime, and getting outdoors and doing things are better than any excessive avoidance strategies! (try helping out with a local kids sports progam - with your own, of course, if you have them) Take up biking, hiking, Xcountry skiing, golf (season and location dependent) It is FAR too easy to spend too much time attached to a keyboard inside - despite the advent of capable portable computers...

This opinion is worth the full $.02.