Reynardine.

Of course they aren't real. Vampirism would be like an incurable communicable disease. One vampire could infect many people who would, in turn, infect many more people. If vampires had been real ever since the first tales of them were told, the entire population of the earth would be vampires now and the world would have run out of suitable bitees a long time ago, so the vampires would be pretty hungry.

Werewolves, however, are a completely different story. Some of my best friends are werewolves. Unfortunately, you can have thousands of the polite ones. One anti-social werewolf goes around eating people, and people think they're ALL like that. Stereotypes bite!