Two decades of battle against polio: opening a window to examine public health in China.

During a two-decade battle against polio, the Chinese government has saved more than one million children from physical disability caused by wild poliovirus infection. Today, the Chinese government still faces an arduous task in (1) preventing the entry and transmission of wild poliovirus from surrounding polio-endemic countries, (2) finding and stopping the outbreak of polio caused by the recycling of vaccine-derived poliovirus, (3) reducing vaccine-associated paralytic poliomyelitis (VAPP) cases, and (4) improving the State compensation system. The scientific monitoring system established in China and the immunity strategy implemented not only allow children in China to avoid lifelong disability or premature death due to polio infection, but also provide success stories for the World Health Organization that can be used for the specification of quality control indices for monitoring polio, classification and diagnosis criteria for acute flaccid paralysis cases, and identification and emergency treatment principles for imported wild poliovirus.