I read a book last summer and can't remember a what it is for the life for me?

The book was about the government taking 8 serial killers and a little girl who are taken to a facility in colorado where they are infected with a disease found from another person. They turn in to vampire like creatures that overrun humanity. The second part of the story takes place in a small compound of survivors after they find the little girl. Eventually their power is dying so they must move on...