From a National Geographic YouTube video published on Mar 5, 2015

A crippling polio outbreak has struck children in the conflict zone of Syria. A group of dedicated volunteers are risking their lives to vaccinate children in areas held by the Islamic State (also called ISIS), often working in areas targeted by airstrikes. Because these war-torn areas lack proper medical services, the volunteer vaccinators feel it is their duty to save Syria's children.

 
(Joan Fisher, District Polio Co-Chair)