We get sick every single time we go to Disney (afterwards though, not usually while we are there). And we don't normally get sick otherwise. I think it is a combination of not eating as well while we are gone (nutrition/weakened immune system) and then of course all the tons of people there. A lot of people do not cancel their vacations just because they have a cold or whatever since they have been planning it for so long. So that combined with all the people there touching every surface, it just spreads so quick.