Peeps by Scott Westerfeld

Opening lines:

After a year of hunting, I finally caught up with Sarah. It turned out she’d been hiding in New Jersey, which broke my heart. I mean, Hoboken? Sarah was always head-over-heels in love with Manhattan. For her, New York was like another Elvis, the King remade of bricks, steel, and granite. The rest of the world was a vast extension of her parents’ basement, the last place she wanted to wind up. No wonder she’d had to leave when the disease took hold of her mind. Peeps always run from the things they used to love.