We do vitamins regularly, on top of making sure they eat healthy (lots of veggies and fruit every day, with milk and 100% juice as oppossed to any soda/kool-aid/etc). Plus, regular washing of hands, hand sanitizer spottting whenever I can remember (whenever we're waiting in line and before snacks) and just basic common sense. I doubt airborne really makes much of a difference, and most definitely doesn't take the place of a good healthy diet and common sense.
Kids and adults are going to get sick, there's no avoiding it. You can do some things to limit your chances, but you're never 100% safe unless you live in a bubble. Just be prepared if it does happen.