Eradicating polio is hard. It is even harder when politicians and imams fan the conspiracy theory that the polio vaccine is part of a Western plot to sterilise Muslims, as happened for several years in northern Nigeria. So in 2015 Nigeria’s president, Muhammadu Buhari, decided to set an example. He gave the vaccine to one of his grandchildren on television, before rallying politicians and tribal leaders to join the campaign.
His efforts, and those of hundreds of thousands of volunteers, have paid off. On August 21st Nigeria marked three years since its last documented case of wild polio. That means the country is set to be declared polio-free by the World Health Organisation-backed Global Polio Eradication Initiative. If that happens, probably next year, all of Africa will be officially free of the virus. Polio will remain in only Afghanistan and Pakistan; and one day it will be completely eradicated, like smallpox was in 1980.