The best suggestions I have for anyone visiting Vegas (in terms of maintaining health) are:
1) Nasal irrigation (probably not going to be popular). Many over the counter products are available, personally I like the Neilmed (I have no affiliation).
2) Properly wash your hands frequently (not the couple of seconds pass you hands under running water that most people do, actually wash them)
3) Drink a lot of water.
Easy to overlook when you're having fun, but I feel it will definitely help.
Sounds like good advice for anywhere you go.