Actually, that's really sad indeed, and nothing to joke about (in case anyone was planning to do so). This is quite serious indeed.
I'm glad I didn't go to PAX, no doubt about it, but people need to be careful any where they are. Heck, someone could have had it at KCon and we don't yet know it.
Hopefully no one from KCon will get sick, but it never hurts to play it safe... Always wash your hands in the bathroom and before eating, don't share food or drinks with other people, stay away from anyone who acts sickly... Oh, and you should probably keep your distance from hobos too.
It's a good idea to keep some hand sanitizer with you too, as other people have already, and just use it every so often just in case... I'd also recommend taking vitamins. Not just for the flu, but just for general health. I take a vitamin C pill every day, and I must admit I feel better since I've started doing that.