It's amazing just how many people on here always get some sort of sickness after a WDW visit, pre Covid.
We go once a year, and one of us always gets sick usually the day before we leave. It's always respiratory related with bronchitis, strep throat, sinus infections. One time I got the sickest I have ever been on our last 2 days of our trip to disney. It was horrible with night sweats (I got up in the night and showered with my nightgown on it was so bad), high fever, cough, sore throat, fatigue, nausea. That was the worst any of us have been at disney.
We always know that one of us will get some sort of respiratory illness on our yearly visits. It was just a fact.
My daughter brought antibiotics with her in case her family got sick (given by her doctor as they always got some sort of bacterial infection while at disney).
I don't know how visitors cannot get sick while at disney. It is a petrie dish of illnesses from all over the US and the world. If someone is sick before their trip, they won't cancel. Paying thousands of dollars for the trip with all the plans that are involved? I don't think too many would cancel, just thinking it would go away. With hundreds of people in close contact every day, it shouldn't be a surprise that alot of people get sick while at disney. (not talking about covid)
About covid: We were at disney Feb 27 to March 4th, 2020, right before the virus hit. We did not get sick at all.