Since apparently there's a topic of vampires, I'm gonna go note down my earlier concept for turning for vampire!Vincent! (Note, this one is drawing on the book, which I have only partially read).
Vincent was turned by the doctor who helped him after the car bomb, in order to save his life - he had otherwise not been going to survive. However, in this version turning is a slow rather than more immediate process - it's started, its happening, it was able to save his life (-well, depending on if one considers vampires to be living, but), but it's going to happen over time, and it'll be a while before it gets to the point of obvious or evident.
But, the rest of their interaction proceeds as in canon - the doctor does tell Vincent about what he's found, and doesn't tell him about what else he's also done. (He does this for two reasons: first, given he's already throwing this one thing at a man who also already just nearly died, he doesn't want to add yet another thing right then. Second, he doesn't really know Vincent so well, and wants to be able to get a better idea of him before he reveals a secret with such ramifications.)
So Vincent - has his dark time, and goes to Rome, and tries to resign, and has his conversation(s) with the Holy Father, and makes plans, and thinks, and prays, and changes some plans, and is starting to come to this greater understanding and acceptance of himself.
And then, when he is back at his home, the doctor comes to talk to him. (Or possibly even he's starting to notice things, starting to not really be able to ignore noticing things, and then the doctor comes to talk to him.) And he has a whole new thing to deal with, and he's going to need to talk to the Holy Father again.
(If I remember correctly, in the book Vincent later says that the doctor who treated him was since killed. In this version that's a cover story, to keep anyone from asking more questions or looking for the doctor, to protect him both in his general (common to vampires) desire to not be known, and about this in particular.)