Polio is a highly infectious viral disease that can cause permanent paralysis and can be fatal in some cases when muscles used for breathing are affected. There is no cure, but vaccination can protect people for life and lead to eradication of the disease.
In 2020, all forty-seven countries of the World Health Organization (WHO) African Region were declared free of wild polio after four years passed without any cases of the virus. This was achieved through a program of vaccination and disease surveillance led by the Global Polio Eradication Initiative, the largest international public health initiative in history. There is, however, still a risk posed by vaccine-derived polioviruses, rare strains of poliovirus that have mutated from the weakened virus present in the oral vaccine. Polio remains endemic in two countries: Afghanistan and Pakistan.