Perception is what matters to the stock price. With all the publicity the stock will jump, and that's what you want short term. Long term, it's a mistake to bank on gains from vaccine sales...in fact this could even turn out to be very costly for the company as flu-related medicines disappear very soon, and you don't hear a thing about the swine flu any more.
Perception! Do you think the hundreds of speculators out there give a darn whether they make vaccines or not? Most of them think GILD has a major role to play and that's what matters for short-term traders. Try the long term approach and post here after you get taken to the cleaners, buddy.