Over the last two years, the Global Polio Eradication Initiative (GPEI), a private-public partnership that has reduced polio worldwide by 99% since its launch in 1988, has greatly expanded the coverage of polio vaccination in Pakistan, Afghanistan, and Nigeria—the three countries where polio is still endemic and the success of the GPEI had previously been more limited. In Pakistan, the proportion of the highest-risk districts achieving the target vaccination threshold of 95% increased from 59% in January 2012 to a peak of 74% in October 2012.