One of the writers at Lawyers Guns & Money has run a policy simulation based on a scenario that posits the emergence of Vampires. Well worth a read:
http://lefarkins.blogspot.com/2010/01/return-of-vampires.html My one concern would be that many of these policies--microchipping, registration and similar restrictions of liberty for Vampiric-Americans--will only drive a substantial and dangerous number of vampires underground (heh).