In northern Nigeria—a country that had previously checked in as provisionally polio-free—a group of Islamic religious figures issued a ruling, or fatwa, that declared the polio vaccine to be a conspiracy by the United States (and, amazingly, the United Nations) against the Muslim faith. The drops were designed, said these mullahs, to sterilize the true believers. Their intention and effect was genocidal. Nobody was to swallow them, or administer them to infants. Within months, polio was back,
