Report: 20 cases of wild poliovirus type 1 in China

Report: Outbreak of wild poliovirus type 1 in China: 20 cases reported
20 December 2011
WHO Europe website

As of 14 December 2011, China has reported 20 cases of wild poliovirus since the outbreak began in August 2011. Of the 20 cases, 11 cases are in adults 19-53 years of age and 9 cases are in children under 3-years-old. The latest case had an onset date of 9 October 2011, and all cases are from the Xinjiang Uygur Autonomous Region of western China.

The Ministry of Health of China has responded to the outbreak by conducting supplementary immunization activities (SIAs) on 8-12 September 2011, which targeted children under 15 years of age and reached a total of 4,065,033 children. A second round, also targeting children age 15 and under was carried out on 8-12 October and reached 4,150,575 children. Vaccination rounds targeting individuals age 15-39 have taken place in a number of prefectures since September 13 and more than 4 million people have been immunized.

Most recently, a third immunization round targeting both children under 15 and adults 15-39 took place on 15-22 November. External WHO and UNICEF monitors reported high coverage, as experienced in previous immunization rounds. The next round of polio SIAs is planned for March 2012.

The Regional Commission for the Certification of Poliomyelitis Eradication in the Western Pacific Region (RCC) met on 14-19 December 2011 in Ha Noi, Viet Nam. At this meeting, the RCC commended China for its efforts to investigate and respond to the polio outbreak, but it concluded that it was too early to determine whether the outbreak is coming under control. In order for the Region to retain its polio-free certification, 12 months must elapse following the most recent polio case or wild poliovirus isolate (i.e. including the high transmission season of 2012), with surveillance indicators meeting all sensitivity criteria.

WHO notes that wild poliovirus transmission could persist during the low transmission season. Therefore it recommends that the Ministry of Health in China should consider implementing a non-selective, universal mOPV1 vaccination policy for all children younger than 15 years of age during measles SIAs planned for December. Updates about the polio situation in China can be viewed at the WHO Western Pacific Region web site (see link at right).

As in the past, WHO/Europe urges all Member States to remain vigilant and ensure enhanced polio surveillance for wild poliovirus importations and to maintain high coverage with polio vaccine. This is of particular importance for countries with intensive travel and trade routes with China. All those traveling to and from countries or areas reporting wild poliovirus should be vaccinated as per WHO’s international travel and health recommendations.