China Tackles Polio Outbreak In Xinjiang Uyghur Region With Vaccination Campaign

Chinese authorities are responding to a polio outbreak in the Xinjiang region with an aggressive immunization campaign. The wild poliovirus type 1 (WPV1) strain is said to have spread from Pakistan.

AsianScientist (Sep. 22, 2011) – Chinese authorities continue to respond aggressively to a polio outbreak in the western part of the country, in the Xinjiang Uyghur Autonomous Region.

The spread of polio from Pakistan to China after the country had been polio-free for over 10 years is a sober reminder to all countries in the region to maintain strong vigilance, said the Global Polio Eradication Initiative.

The last wild polio virus (WPV) case in China was reported in 1999, due to an importation from India. The last indigenous polio case occurred in China in 1994.

To date ten polio cases have been reported in Hotan Prefecture; six in children under 3 years of age and four in young adults – one person has died.

An initial response vaccination campaign was held by the Ministry of Health on September 8-12 and targeting 3.8 million children aged under 15 years in the key affected outbreak area; followed by around 1 million people after September 13.

Vaccination for approximately 4.5 million persons 15-39 years old in other prefectures in southern Xinjiang (Aksu, Bazhou, Kashgar, and Kezhou) commences tomorrow, on September 23.

The polio immunization campaigns go house-to-house, to kindergartens, schools and the workplace, to markets, bus stations and airports in order to ensure that no one misses the vaccine. Children are also marked with indelible ink behind their ears as a way of tracking whether they have been vaccinated.


The origin of the wild polio virus 1 (WPV1) strain in China

Genetic sequencing of the isolated viruses indicates the wild poliovirus type 1 (WPV1) strain found in China are genetically-related to viruses currently circulating in Pakistan.

As of 13 September 2011, Pakistan had reported 84 cases of WPV1, compared to 48 cases for the same period in 2010. It is also the location of the only wild poliovirus type 3 (WPV3) case in Asia in 2011, a strain on the verge of elimination on the continent.

However, supplementary immunization activities (SIAs) in Pakistan this year have been inadequate in quality, especially in the security-compromised parts of the Federally Administered Tribal Areas (FATA).

In particular, an upwards of 200,000 children in Khyber agency have been regularly missed during SIAs conducted during the past two years. Also, significant operational challenges continue to mar the quality of SIAs in the provinces of Balochistan and Sindh.

Given the widespread transmission of WPV1 within Pakistan and to China, and the detection of the only WPV3 in Asia in 2011, the WHO has rated the risk of further international spread of WPV from Pakistan as ‘high’, particularly given the expected large-scale population movements associated with Umrah and the upcoming Hajj pilgrimage.

To urgently address the widespread transmission of wild poliovirus affecting the country, the Government of Pakistan launched a National Polio Emergency Action Plan this year, but has not done so at the critical program implementation level.

While 54 districts of the country have carried out staggered subnational immunization days from September 19 to 21, challenges in accessing populations in security-compromised areas persist.

The WHO recommends that travelers to and from Pakistan should be fully protected by a full course of vaccination, with another dose of oral polio vaccine (OPV) before departure.

Likewise, travelers from Pakistan should have a full course of vaccination against polio before leaving Pakistan, with a minimum one dose of OPV before departure.

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Source: World Health Organization; Global Polio Eradication Initiative.
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