It seems as though aliens are an emerging trend in YA lit. I loved The 5th Wave, but In the After was just as good. It centers on a teenager named Amy living in seclusion with a younger girl she found, who she calls Baby. They live completely in silence so that they don’t attract the attentions of Them, the green aliens who eat humans alive.
Anyways, this book was excellent. You can read my review here.