On July 24, Nigeria marked one full year without a single new case of locally acquired polio, the crippling and sometimes fatal disease. It is the last country in Africa to stop transmission of wild polio. This milestone represents a huge victory — one that some experts feared would never come. It required mapping every settlement in the north of the country, counting all the children in every house, delivering oral polio vaccine several times a year, working with hundreds of thousands of traditional leaders and community mobilizers, and operating in areas dominated by extremist groups. Nigeria’s efforts show that smart strategies can work even under the most difficult conditions. When the global campaign to eradicate polio began in 1988, polio was endemic in 125 countries. The list is now down to just two: Afghanistan and Pakistan. We’ve come more than 99 percent of the way to eradication. I am confident we can finish the job.