You would hope they are healthier than most, I'm not sure about "go to the doctor" but they have regular full STI checks due to the nature of their job, and they work with other adults who are regularly checked and cleared. Depending on how much sex they have off-camera, there is a good chance an awful lot of them are less likely to contract something nasty than Average Joe who goes out on the pull every weekend, never bothers to rubber up, has no idea of the sexual history of his unfortunate jizz receptacle and never gets himself checked.