It depends. I'm likely to get a cold. I live with kids and work around kids. They don't typically last very long. Bronchitis I have not had since college days. I do get the flu shot. I try to stay away from hospitals, actually my last neuro banned me from er visits because of my own immune system. I brought home a staph infection and the flu after coming home from the hospital with my youngest.
I cannot recall the last time I needed medical clearance to return to work. A day or two home from work from a cold is perhaps the usual for me. Depends on how run down I feel from it.