Two Afghan policemen stand as an Afghan health worker administers polio vaccine drops to a child on the last day of a vaccination campaign in Ghazni on March 17, 2015. Nearly nine million children throughout Afghanistan will be immunized during a three-day national polio immunization drive launched on March 15. AFP PHOTO / Rahmatullah Alizadah (Photo credit should read Rahmatullah Alizadah/AFP via Getty Images)
