Reminds me of Anno Dracula
At least I think that's what the title of the book was. Granted, there are differences in time and such...but the general idea of humans and vampires co-existing in an alternate time matches.
In the book, Dracula was never killed by Van Helsing and spreads the plague throughout the world. It was weird reading about vampire prostitutes and vampires in welfare homes, as well as vampires in positions of status and participating in "high tea" by drinking from obliging serving personnel. Also has a serial killer spin on it as well.
Great book. Highly recommended.