I work in a hospital. Filth and pestilence EVERYWHERE lol.I handle money all day, and I rarely wash my hands, I know sounds gross as hell, but I think it's helped keep my immune system pretty strong.
Stay away from hand sanitizer (unless you are touching poop and rotting and that kinda thing), I think it kills germs but your body needs to encounter some germs to build immunities. I used to get sick all the time, but I quit smoking and got my tonsils out and I get maybe one cold a year. Even when I get colds i just drink juice and water and they only last 3-4 days that way and are never that bad.
Just my thoughts....