Here's what you do:

Alcohol swab the cockpit if you can
Wash your hands every chance you get
Take vitamins to boost immunity
If you feel a cold coming on, take Zicam. Works for me
And by all means, unless you are projectile vomiting or have the constant squirts, be a man, suck it up and don't whine. Calling in sick is a guaranteed carpet dance in the chief pilots office.

Just my $.02