Status of the eradication of indigenous wild poliomyelitis in the People's Republic of China.

A large nationwide outbreak occurred in 1989-1990 in China, in which nearly 10,000 poliomyelitis cases were reported. After two rounds of oral poliovirus vaccine (OPV) supplemental activity in nearly every province in the 1992-1993 winter season, no wild poliovirus was detected in 1993 in 22 provinces in the middle of China that contained 86% of the population. During the first national immunization days (NIDs) conducted in December 1993 and January 1994, 83 million children 0-47 months of age were immunized. In 1994, wild poliovirus was identified in only 6 of 2397 children with stool specimens tested. After a second NID in December 1994 and January 1995, no wild poliovirus was detected in 1995 despite a very high level of virus surveillance. In summary, double-round mass supplemental OPV immunizations in children 0-3 years old in two consecutive winters eliminated wild poliovirus from 23% of the world's population (1.2 billion people).