Article from National Geographic (of all things) says “Influenza germs last longer … in lower absolute humidity — i.e., when it’s cold outside and the air is dryer.” So, once again, consider carrying a saline spray inhaler. The brand Ocean, and others, are in the nose ailment department of your local drug shop. For two or three bucks. They keep your insides damp and healthy on airplanes, air conditioned hotels and offices, and Aunt Harriet’s overheated apartment. Beat the flu and colds. Feel superior. Dr. Tom says Do This Thing.