A student gets vaccinated against pertussis at a Los Angeles middle school in 2012. The state required that students be immunized to halt an epidemic of whooping cough.
Kevork Djansezian/Getty Images
Arefa with Jami Valentine (left) and Staci Freeman. Arefa, who first stayed with the sisters while receiving medical care last year, came back to the U.S. this summer for follow-up treatment.
Gloria Hillard for NPR