Vampires in the NS universe are not undead, but rather a living species of the night. Vampires can however pass some of their traits onto creatures they have eaten off too frequently. However, a person (or animal) killed in one feeding will not return as one of the undead, and instead will simply be dead.
Vampires also do not prey on victims in the streets, at least not anymore. As the world has modernized, so have the vampires, who are now an accepted part of society in the T.C.A.. Prior to the foundation of T.C.A. vampires generally travelled in packs or clans, ruled only by their own kind. Since that time however, as part of their acceptance into the T.C.A., those pack and clans were dissolved, though many still claim to be royalty through those old ways.