Few jobs ago I had "desk neighbour" that no matter how sick he was (seasonal flu and so on), he was coming to work. One time I've asked him why he wouldn't take sick leave (which is paid leave, 80% but still) and he said, that he's not staying home so he wouldn't infect his kids... Of course every time he was sick, I was getting sick. Which is natural consequence of sitting 1.5m from someone sneezing/coughing for a week.