Unsure. I work from home so my exposure to germs is already pretty minimal, however, I did take a trip to SF about two weeks before I showed symptoms. My girlfriend is also a school teacher so she ends up bringing a lot of colds home. She never (and still hasn't) showed any major symptoms other than a small fever that lasted just a day or two a week after we got back from SF (although she could have been an asymptomatic carrier).