To some degree. In short - yes. We all have ghosts. Can they manifest? I've never seen it happen and I'm not certain it's possible. I would hope it is. I've heard vampires and werewolves are real. It isn't quite what we've been told. The reasoning and even the biology was explained to me long ago. I don't know if ghosts are in existence or possible (there is a difference). It's certainly a more interesting world if ghosts were real.
I rather hate when people make fun of goths and Twilight. They don't understand very much.
As a sort of proof, crosses and crucifixes work well on humans - let alone vampires. Vampires react much more strongly because of their history and need for blasphemy - which provokes a depressing state for them.
I've heard three people from my past (whom I had little to do with) became vampires - Jasmine McAvoy, Kelly Allen & Linda Nicholls. They are presumed missing or are unaccounted for by their loved ones. BTW (somewhat ironically - but not really) Kelly Allen is related to Krys Force of Amber Asylum. I had a huge crush on Kelly when we went to Hexford. I still desire her but she feigned her Christianity and was a lifelong atheist with somewhat agnostic tendencies - if that makes sense.
Note, one can argue we are all ghosts. We are all physical manifestations of our own life ghost.