A World Without Polio

When this journal last published a special supplement on polio nearly 18 years ago, we lived in a world that was still deeply entangled with this devastating virus All 3 poliovirus serotypes were still circulating on four continents. Some of the world's largest countries remained mired in the disease, some with thousands of cases each year. Most tellingly, a number of polioinfected countries, particularly in Africa, had not even introduced core eradication strategies, such as polio national immunization days (NIDs). Both financial and human resources were stretched; worldwide, <250 people were employed full time in a program whose success would eventually require, at its peak, reaching and vaccinating >600 million children multiple times per year.