Creepers

When 5th-grader Karin, her high-school brother, Bern, and several other students and their teachers lock themselves inside the high school's gymnasium, the true horror of a viral epidemic unfolding outside their barricaded door is only beginning to become clear. In this short tale, Lord of the Flies meets 28 Days Later as, one by one, grown-ups abandon children to their fates. Desperate and terrified, the kids scrabble their resources together in order to somehow survive, but young Karin and her brother quickly learn that no one is more vulnerable than children.
Or more ruthless.