A couple of decades back, I belonged to a weekly writer's group. A young woman in the group was into Stephen King type stuff and was particularly into vampires (this was before Anne Rice became all that well known). She was working on a novel about a small group of vampires (an endangered species) who had discovered to their horror (!!) that they were particularly susceptible to HIV tainted blood.
Interesting premise. I don't know what ever became of her or her story, though.