You know we probably wouldn't have much issues with vampires if a-holes like Van Helsing didn't try to hunt them down, I mean they're just people who drink blood we could just give them expired blood bags or even just blood from animals. Sure some vampires are pure evil, but the same can be said of some humans.
Edit: Vampires aren't mosquitos, I'm pretty sure we can't reason with mosquitos. Plus the whole having to sleep in dirt filled coffins and the whole sun thing.