“Bad Blood” (*1/2 out of four) was an anemic horror story about a caring social worker (Tosca Bell) who takes in a homeless boy (Brian Dunne) into her care but soon comes to realize he is a vampire and that her life may be in danger but is then at a moral crossroads over what to do about him. Dour-looking and dull; this might give “Twilight” a run for its money for the dullest vampire characters ever. “Bad Movie” would be a much more apt title for this clinker.