Hi, My Son Was Diagnosed By His Pediatrician Today With

Hi,
My son was diagnosed by his pediatrician today with hand, foot, and mouth disease. I work at a living facility with senior citizens. Should I be concerned about how contagious the virus is and not go into work? He's had symptoms for roughly 3 days now and I've been in to work these past 3 days so I guess at this point it wouldn't matter since I would have already exposed people with it.