The last really nasty virus I got was H1N1 (3 years ago)and I rode my bike throughout save for a few days where the lady (who had also had this) forced me to lie down and submit to her ministrations and vile holistic remedies.

The ministrations were okay, the home remedies were worse than the swine flu, and I did run enough of a temperature to burn all those bugs out of my system in pretty short order.

As for colds... canna remember the last time I had a cold but did throw out the good side of my back a few weeks ago and fell down my stairs and sprained both ankles a week ago... that has slowed me down a little but have been riding a little this week as the direction my feet move in when I am pedaling is not the direction that makes things hurt.

I'm definitely pro snot rocket. I first learned the trick from my High School history teacher. He did tell us about it to make us squirm and gross us out (Back in Vietnam we didn't have handkerchiefs, we just....). But man, if it doesn't work better than a hankie. Part of being a man is owning the gross factor. Just aim carefully and with some awareness of your surroundings and all's good.

Oh, and no. I haven't been sick since I started commuting. I feel better than ever. (Just started back in August, though.)

I can also attribute the better sinus health and lack of colds to using a Neti pot regularly... use prevents those nasty bugs from establishing themselves in your sinuses, keeps things moist (really important in a dry climate) and washes out an astounding amount of crud that you get when you ride in traffic and dusty conditions.

Neti's rule. Hard to do while you're biking, tho'.