On that note, it would also be extremely unrealistic. There would be no way for the mediwizards to identify the random sickness and produce enough vaccine for everyone who was at the party, and then everyone who possibly had contact with anyone there. There would be many people dying, and I seriously doubt that so many people want to kill off their student characters.
What was the most unnerving about the swine flu, or bird flu was the panic it caused because it was not easy to spot at first, or that they didn't really know what they were looking at. Would it not be more interesting to play the nervousness over if you have it, or if your friends have it after one suddenly gets sick? Sure some people would pass away faster then others due to things like them having weaker immune systems and the like, but overall most sicknesses are not instant killers. Even those who do die suddenly usually have had the sickness for longer, but haven't shown symptoms, or have ignored them for whatever reason.
All in all, this should be something that takes place over several months with different levels of sickness due to the person's personal immune system, or general stubbornness. H1N1 here in CA lasted about 8 months of panic before the hysteria died down. That would give us plenty of play time for both those sick and recovering, and for your characters who maybe don't give in to the hysteria to have interesting plots about this. It would also be a more realistic for the healers to figure it out and find a vaccine and cure.