[MFLoon]

There's a multitude of good reasons to close the dorms. People are sharing bedrooms, common areas, bathrooms and kitchens with far more people than they would be in the average private domicile. The network effect of communal living, combined with the generally more lax sanitary/hygenic standards of a younger population, makes any dorm highly at risk for becoming a hotspot, of any infectious disease (and indeed it's quite common for colds, flus and even more serious diseases to cause epidemics in college dormitories).