We don't worry about it or stress over it. In all the times we've been to WDW or on cruises, I am the only one who has ever gotten sick, and only once. A couple of years ago I caught the flu and spent the last 3 days in our resort hotel unable to even get out of bed. I'm certain I caught the flu from a guy at the airport who was hacking up a lung. I didn't move seats fast enough I guess
*And I cannot get a flu shot because I am allergic (for all those who love to preach about getting the flu shot).