The strain of polio isolated in the outbreak in China reported earlier this month is genetically linked to the wild poliovirus type 1 (WPV1) currently circulating in Pakistan, according to a Global Alert and Response (GAR) warning from the World Health Organization (WHO) yesterday, 20 September. The organization says this confirms that the wild poliovirus is spreading internationally from Pakistan.
WHO blames inadequate immunization in Pakistan for the spread:
“In 2011, supplementary immunization activities (SIAs) in Pakistan have been inadequate in quality in key high-risk areas,” states their GAR.
Parts of the Federally Administered Tribal Areas (FATA) in Pakistan, where security is weak, and particularly in the Khyber region, 200,000 children and more have not received the polio vaccine in the last two years. There are also “significant operational challenges” affecting immunization in other key transmission areas such as the provinces of Balochistan, which neighbours Iran and Afghanistan to the west, and Sindh, which neighbours India to the east. Also, undetected circulation cannot be ruled out because surveillance itself is patchy.
Compared with last year, the spread of polio appears to be increasing in Pakistan, reports WHO. As of last week, the Pakistan authorities had reported 84 cases of polio, compared to 48 cases for the same period in 2010.
The country is now affected nationwide by transmission of the WPV1 strain, and is also the only country in Asia in 2011 to have the only wild type 3 polio virus, WPV3, which is on the verge of elimination elsewhere on the continent.
Given the spread of WPV1, the fact the country appears to be the only one in Asia where WPV3 remains in 2011, WHO rates the risk of further international spread of WPV from Pakistan as “high”. In giving this rating they also took into consideration the large-scale population movements that are expected to take place with the Umrah and Hajj pilgrimages to Mecca in Saudi Arabia in the next few months.
Earlier this year the government of Pakistan lauched a National Polio Emergency Action Plan. The impact of this plan is not yet visible on the ground, or the “critical programme implementation level”, say the WHO.
To build up immunity to both circulating strains of polio, immunization days are taking place this week, to be closely followed by further activities in high-risk union councils in 54 districts of Pakistan.
But WHO says this will only succeed if there is “full and consistent engagement and accountability at provincial, district and union-council level”.
The organization also urges all countries in Asia and the Eastern Mediterranean to strengthen monitoring of acute flaccid paralysis (AFP) to spot early any signs of polio being imported and to respond fast should this happen. They should also boost routine immunization coverage against all strains of polio just to keep in check any possible imported spread.
Travellers to and from Pakistan should also be fully vaccinated, and travellers to the country who in the past have had three or more doses of oral polio vaccine (OPV) should have another one before they travel.
Some countries require travellers from Pakistan to be fully immunized against polio before they grant an entry visa.
In line with WHO’s International travel and health recommendations, the Kingdom of Saudi Arabia has issued vaccination requirements for travellers of all ages undertaking the Umrah and Hajj pilgrimages. As well as the WHO recommendations, they require that all travellers entering the Kingdom from countries where polio is endemic show proof of having received OPV six weeks before travel, and they will also be given a further dose when they arrive.
Written by Catharine Paddock PhD