Ongoing outbreak of wild poliovirus type 1 in China: WHO/Europe’s recommendations and response
Six additional cases of polio have been reported in China since 26 August 2011, when the Ministry of Health, China, first informed the WHO Western Pacific Regional Office that wild poliovirus type 1 (WPV1) had been isolated from four young children. In addition, WPV1 were found in close contacts and a healthy child. Of the total 10 confirmed paralytic cases to date, six are in children under 3 years of age and four are in young adults ranging in age from 22 to 26 years of age. Onset of paralysis among the children was from 3 to 17 July 2011 and the onset among adults was between 1 August and 6 September 2011. Cases have been reported from western China’s Xinjiang Autonomous Uyghur Region - Hotan prefecture and from Bazhou prefecture to the east of Hotan. This particular region of western China borders Kazakhstan, Kyrgyzstan and Tajikistan of the WHO European Region. On 9 September the Chinese authorities confirmed the death of one of the cases. These findings suggest extensive transmission of wild poliovirus in the Xinjiang Autonomous Uyghur Region.
The Ministry of Health conducted a province-wide immunization campaign beginning 8 September, targeting 3.8 million children under 15 years of age with two rounds of polio immunization and expanded to adults aged 15 to 39 years old in the southern prefectures of the region. The initial results from the campaigns are very promising and international and national partners alike consider the Chinese government's response to this outbreak very comprehensive, rigorous and indicative of the value placed on collaboration and transparency.
Trade, travel and migratory patterns between China and the central Asian Republics indicate the threat this outbreak poses beyond Chinese territory. The risk assessment conducted by WHO in China also indicates a high volume of air traffic between the main airports of Xinjiang Autonomous Uyghur Region and Member States across the European Region. Of the top 14 international air travel destinations from Kashgar and Urumqi, 10 are in the European Region. The outbreak emphasizes the gravitas of the message conveyed to the WHO European Member States on 24 August 2011 by the European Regional Certification Commission for Poliomyelitis Eradication (RCC), when the Commission strongly urged all Member States of the European Region to remain vigilant and alert. On that occasion, the Commission also announced that Europe had retained its polio-free status after the importation of wild poliovirus type 1 in 2010.
Genetic sequencing of the isolated viruses in China indicates that they are genetically related to viruses currently circulating in Pakistan. The last WPV case in China was reported in 1999, due to an importation from India. The last indigenous polio case occurred in China in 1994.
A full investigation of the cases is ongoing. WHO is supporting the Ministry of Health with the ongoing outbreak investigation, immunization response activities and the development of mid-term plans. The WHO Regional Office for Europe is keeping in close communication with the Regional Office for the Western Pacific and has notified neighbouring countries about the outbreak. Furthermore, a detailed risk assessment is nearing completion and Member States are being advised to take precautionary actions, including the implementation of border point awareness and information campaigns, and provision of polio vaccine for those travelers requesting it prior to crossing the border or boarding a flight to China. Neighbouring countries have also been encouraged to strengthen surveillance for cases of acute flaccid paralysis and ensure that all administrative territories are reporting. WHO/Europe is providing technical support for such activities, where required.
The WHO Regional Office for Europe recommends that countries at particular risk – whether because of sub-optimal surveillance or immunity, or because of their proximity or trade and travel connections to a polio-affected area in China – should provide an opportunity to get one supplementary dose of polio vaccine to all concerned individuals, regardless of their age. This could be done through provision of vaccination services at frontier points, international airports or known market places with a high mixture of Chinese and local population.
Restrictions on international travel and trade are not recommended in the case of wild poliovirus detection. Per recommendations outlined in WHO's International travel and health, all travelers to and from countries or areas reporting wild poliovirus should be adequately vaccinated.
Regular updates will be posted by WHO/Europe, along with links to other relevant sites.
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