A Pakistani health worker administers polio drops to a child during a polio vaccination campaign in Peshawar on September 14, 2015. Pakistan is one of only three countries in the world where polio remains endemic but years of efforts to stamp it out have been badly hit by reluctance from parents, opposition from militants and attacks on immunisation teams. AFP PHOTO / A MAJEED        (Photo credit should read A Majeed/AFP/Getty Images)