In Scandinavia it was believed that the dead were alive in their barrows (an ancient burial mound) and the story from the Norsemen, The Grettus Saga stated that the living dead in these barrows might turned into vampires. For Scandinavia, their ghosts were physically dangerous like vampires than the usual apparition, which that is according to K.M. Briggs' Anatomy of Puck.
In Denmark, the Mara was a female vampire who went around during the day in human form. If you fell in love with this fiendish vampire, one would experience feelings of suffocation and strangulation around the neck! In Iceland there is a saga called, Eyrbyggia Saga (The Saga of the People of Eyri) which in one of part of the saga, it talks about a vampire in the year 1000 who killed 18 servants in a household. Finland has a tale about spirits that are around when you're under illness like a fever. You can think of it has a vampire because it sounds like it drains the energy.
The last tale that deals with Scandinavian folklore is about the vampire spirit of Aswid. The story states that the man came back from life and devoured his horse and dog. His friend, was lucky enough to have escaped. So that's just some of the tidbits that you can find about vampires in Scandinavian folklore.
The Natural History of the Vampire by Anthony Masters