It seems to happen every fall semester. At Thanksgiving time, my students go home to see their families and exchange viruses. Then, during the last week of classes, during their final presentations, the classroom is filled with sniffling and coughing. As I’m grading their portfolios, I start to feel my sinuses filling, and I need a box of tissues at my side. By the time I submit their final grades, I’ve come down with a miserable cold.