Back Story for my Novel

Freya is a 600 year old Vampire. She came to the USA back in 18th century. She and her family moved to Nelson County Virginia. In 1976 when the Swine Flu vaccine was given to all who lived in America it was the end to all Vampires. If they fed on people or tried to do an Embrace they and the human would die. It was later found out that the humans put VGR (Vampire Growth Regulator) in the vaccine. She has 2 other siblings, they have vengeance in their hearts. It is up to Freya to keep the peace between the two races.