Back story for my Antagonist.

The human race noticed an epidemic every 55 years. After research they noticed it was caused by vampires. They created a weapon unlike anything ever recorded. This weapon was Vampire Growth Regulator (VGR). It's purpose was if a vampire fed on a human the vampire would die and if a vampire attempted to turn the human into a vampire the human would die. In 1973 this weapon was given to all Americans in the form of a vaccine. By the mid 80's this was turned into a form of pesticide for the corn crops. By the mid 90's this was now inside anything that was a byproduct of corn. Such as in the livestock who ate the corn, talcum powder, toothpaste, baby food, peanut butter, many distilled products-gin, vodka, whiskey, and chewing gum. By now any and all who come to America will ingest or use the VGR. This has caused the vampires a great deal of pain and suffering.
Yet at the same time it has caused the humans to relish in their victory over a race that was once superior to them in many ways. But with this creation the tide has turned and is now in their favor. For this they are greatly relieved and overjoyed.