In this October 20, 2013, file photo released by UNICEF, a Syrian student receives a vaccination as part of a UNICEF-supported vaccination campaign at a school in Damascus, Syria. (AP Photo/UNICEF, Omar Sanadiki, File)
In this October 20, 2013, file photo released by UNICEF, a Syrian student receives a vaccination as part of a UNICEF-supported vaccination campaign at a school in Damascus, Syria. (AP Photo/UNICEF, Omar Sanadiki, File)