This is a post for those who watch vampire movies and/or read vampire books. Have you ever wondered why it is that, in the old tales, vampires (vrykolakas) react to Christian symbols?
Like the mark of Cain, vampires received the mark of Judas. Because they betrayed the Cross, because they betrayed the True Light, because they used wood soaked with the blood of Christ, because they used the blood of the Betrayer, they cannot stand the symbols of Christianity; they cannot come into sacred ground. Mind you, Father Orthoduck cannot explain the garlic of Bram Stoker, but then, this author does not make them allergic to garlic. This also explains why they are not vulnerable to any other symbol of faith. They are the descendants of Judas.