By Priyanka Khanna and Jasmine Pittenger
After her daughter was stricken with polio because she was not vaccinated, a mother goes door-to-door in her Nigerian village to make sure other children get their vaccines.
HAWAN DAKI, Nigeria, 8 May 2013 – Aisha may not be able to read, but she never forgets a name, or a child.
"Where are Hassan, Hassana and the other kids?" Aisha asks the woman of the house as she stands in the doorway.
Hassana is in, but Hassan is outside,” says their mother.