I know about various fictional and folkloric vampire mythoses the way other people know about the personal life of celebrities.
One of the things that may appeal to teenagers is that vampires never change - they're frozen in that age.
Back when I was growing up, getting caught with a copy of 'Creepy,' 'Eerie' or 'Vampirella' was almost as bad as your parents finding out you were reading 'Playboy.'
I became a horror fan during the early 1960s, back when Hammer was putting out their groundbreaking 'Dracula' series with Christopher Lee and Peter Cushing, and grew up watching 'Dark Shadows.'
Vampires are handy characters, as they can do double duty as monster/villains and the classic, misunderstood romantic hero.
The vampires in the 'VAMPS' series judge each other as harshly as they judge humans, and basically, vampires don't get along very well. So you've got a culture that's from cradle to grave like the worst high school you've ever been in.
The best advice I got as a writer was also the first advice, which came from the late fantasy author and editor Karl Edward Wagner: Any agent who charges to look at your work is a crook.
Horror serves a cathartic role in human society, all throughout the world. It is a way of confronting the darkness, both within and without.