According to a British study, you’re six times more likely to get an acute respiratory disease if you’ve ridden the subway or bus recently. This should surprise no one. It’s already common knowledge that mass transportation spreads illnesses just ask Joe Biden and we’ve all sat near the Guy Whose Whooping Cough You Can Hear Over Your Music at some point. But the good news is that by venturing into this disease factory every day, you build up an immunity to many viruses. So if you come across Pungent Sleeping Homeless Man in the above-ground world, don’t sweat it. You already have a little piece of him inside of you, keeping you safe.