The Radleys by Matt Haig 369 pages

Teen Rowan is constantly picked on by the school bully and his younger sister Clara has just become a vegan. When she is attacked by a classmate, Clara has a violent reaction -- she transforms into a vampire and slays him. Her parents had tried to deny their existence by following the guidelines written in The Abstainer's Handbook. This act causes many repercussions. Mother, Helen sends a telepathic message out to her brother-in-law (and father of Rowan), Will. Will is happy to return -- after hundreds of other conquests he has decided that Helen is the one for him. Unfortunately, Peter his brother is in the way and the vampire police is hot on his trail because of his flagrant killings. Before you know it the cat is out of the bag when the kids learn their true identity and the power of consumed blood. This is hardly a typical teen vampire story -- it is marketed for adults. There is a lot of tongue-in-cheek humor and it has been optioned to become translated into film.