This is a great dystopian novel that I read in a long car trip, then immediately got the sequel.
In this great book, the bees are dying. The government does something to the bees to make them resistant to viruses and pesticides and stuff. Then, the bees sting people which causes the people to die. The government gives a vaccine to people who will be good for the future. When these vaccinated people start turning into monsters, or Beasts, the government does something that kills all life and people set up colonies with protection against the monsters and bad people. Then, a girl named Fiona wakes up outside a colony without remembering when she fell asleep. It turns out she had been cured and now has to navigate a dangerous and destroyed world with the help of a friend, and figure out how to get back safely. Along the way she discovers traitors, friends, bad people, and a horrid use for Beasts.
I would say 13+ for blood, gore, violence, mentions of a group of people that rape woman, and some kissing scenes. Very good book and the sequel is called Cured.