Which Came First? The Chicken or the Flu Egg?

We go through the entire spring and summer - no influenza. Early in the fall, the flu shot is offered and most people I know get it. Some time a little later in the fall, the flu is rampant. What exactly is the evolution of the flu? Which came first - the chicken or the egg? Was it the flu shot that caused it or did it just evolve?

I guess I don't understand the evolution of the cold either. Where does it come from? This summer I've known quite a few people who had colds. Typically though, we go through the whole summer without any until fall.

Hmmm.....

Added note: According to Doctor Oz, the flu starts in Asia. I wonder why...would it have anything to do with Asia being a little over-populated?