There are too many vampire lores to count, who knows?
I know in Buffy, only Christian crosses and holy water worked. But Joss was never fond of digging into his own mythos, so the why was explained behind the scenes, in that vampires pissed off the church, and the church added a little magic to their ceremonies.
In Harry Dresden, objects of faith work the same in the MU. As long as they are a believer, they'll repel vampires.