Peeps by Scott Westerfeld

This is a teen book but very good. A different kind of vampire novel. In this novel, more and more of the earth's population is being infected with a parasite. This parasite drives them insane, makes them stay away from sunlight, and crave blood. The infected are called Parasite Positives, or Peeps for short. Cal is unusual. He was infected when he was nineteen and had a one-night stand with a mysterious woman he met in a bar. BUT, he has been able to suppress the insanity and blood-lust. He is a carrier: super-human strength, and able to see in the dark, but still maintaining his sanity. And as for blood, usually just eating lots of red meat helps.

Since the parasite is tranferred through bodily fluids, Cal must be careful not to get to close to anyone. If he even kisses someone, the parasite can be transferred. And unfortunately, the parasite really makes him crave intimate companionship. So he limits his contact to other carriers in a secret organization known as the Night Watch. An organization older than the county itself, dedicated to stopping the parasite invasion. Until the day he meets a woman named Lace on a routine assignment, who really starts to test his resolve.