Pretty much what teenagers now flip out about whenever somebody cough, sneeze, have a snotty nose, a little stomach cramp, etc. It could be hay fever or food poisoning or just for running in track too hard.
Also, another excuse for the people who make hand sanitizers to make a few extra buck because we are in a "recession". Remember Y2K?
*somebody coughs because of a tickle in the throat or something*
Teen: Oh my gosh, I got like the swine flu
Teen 2: We are all going to die. Stay away from me!!