You end up with highly contagious pathogens that you'd never find in your home (Hand, Foot & Mouth, for example) and higher incidence of things like conjunctivi

You end up with highly contagious pathogens that you'd never find in your home (Hand, Foot & Mouth, for example) and higher incidence of things like conjunctivitis, but since everyone in licensed group care facilities is vaccinated against the real baddies, that stuff is no more frequent. What parents bank on is that the persistent coughs & colds that are so common will eventually lead to stronger immune systems. As a parent of 2 elementary school kids who both did group daycare/preschool, I have 0 useful data to share. My kids got sick regularly in preschool, don't get sick as often in elementary school, but when one gets sick (with a viral infection) generally everyone else in the family still gets sick, too.