Identification and Control of a Poliomyelitis Outbreak in Xinjiang, China

China had been free of wild-type poliovirus transmission and infection for nearly 20 years when a 2011 outbreak of imported wild-type poliovirus was identified in Xinjiang. Efforts to control the outbreak are described, including the administration of 44 million doses of vaccine. The World Health Assembly established the Global Polio Eradication Initiative in 1988. 1 , 2 The World Health Organization (WHO) Western Pacific region, including China, was certified as a poliomyelitis-free region in 2000. 3 However, the transmission of wild-type poliovirus has not yet been stopped in Afghanistan, Pakistan, or Nigeria. Globally, some countries have had outbreaks of imported wild-type poliovirus, and in others the circulation of outbreak strains has been reestablished. 4 China has the world's largest population (1.347 billion in 2011). 5 By 1963, live, attenuated oral poliovirus vaccine (OPV) was being administered in annual campaigns conducted during the winter. OPV has been included . . .