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Saturday, 6th of March 2010 Print

From The Lancet Infectious Diseases.
We have seen articles like this before. But this time we are seeing early 2010 data which support the author's upbeat view.
According to http://www.polioeradication.org/casecount.asp there were 34 WPV cases through 2 March 2010, compared to 91 in the same period of 2009. Most of the decline was in Nigeria,  which has had 1 WPV case in 2010 to date, compared to 42 cases in the comparable period of last year.
Good reading.
The Lancet Infectious Diseases
The Lancet Infectious Diseases, Volume 10, Issue 3, Pages 148 - 149, March 2010
doi:10.1016/S1473-3099(10)70036-0Cite or Link Using DOI

Polio eradication within 5 years now a real possibility

Last year was a significant one for polio eradication. Real progress was made simultaneously in northern Nigeria, on the Afghanistan—Pakistan border, and in the remaining pockets in Bihar and Uttar Pradesh in India, cutting the number of cases worldwide to 1597 (correct as of Feb 2, 2010). The new bivalent oral polio vaccine (bOPV), which targets type 1 and type 3 polioviruses, was licensed in late 2009 and has been in use since December. Starting in February, March, and April, 2010, multiple mass immunisations are planned in all four remaining countries where polio is endemic, at the start of a 3-year intensive effort to finally halt polio transmission worldwide.
African leaders have made the decision to run synchronised mass polio immunisation days on March 6 and April 23 across almost all of west and central Africa, targeting over 85 million children in 19 countries. “This was spurred mainly by the tremendous progress made in Nigeria in 2009 and made possible by an emergency grant of over US$30 million by Rotary International”, reports Bruce Aylward (Director of the Polio Eradication Initiative, WHO, Geneva, Switzerland). Muhammad Ali Pate, Executive Director of the National Primary Health Care Development Agency in Nigeria confirms that 800 cases of polio were recorded in his country in 2008; 90% of which were due to the type 1 poliovirus. “By the end of 2009, we had 388 cases with only 28 cases in the last half of the year. The last type 1 case was at the end of October, 2009, and we have seen only one case of polio in Nigeria so far in 2010—a type 3 case in Bomadi in the Delta State in southern Nigeria”, says Pate. Vaccinations are currently underway in northern Nigeria with the bOPV, which was deployed for the first time in January.
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Full-size image (59K) Cornelia Walther/UNICEF
A child receives bivalent oral polio vaccine in Jalalabad, Afghanistan
It will soon be 12 months since type 1 poliovirus was last detected in Kano, Nigeria, the state that stopped vaccinating against polio between 2003 and 2004, leading to an unprecedented international epidemic that took years and millions of US dollars to control. The turnaround is because of strengthened political commitment to polio eradication. Pate told TLID that all the funds for immunisation were released to him in the third quarter of 2009, allowing full-scale immunisation to proceed unhindered. “We have also made progress at grass roots level to solve important non-compliance issues”, he explained. The country's governors have lent their support to the campaign and the Northern traditional leaders have never before been so systemically involved in polio eradication efforts, providing renewed optimism for Nigerian and pan-African polio eradication.
The well orchestrated effort at the start of 2010 to reduce transmission over the whole of Africa is happening as renewed impetus for mass vaccination programme in the Indian states of Bihar and Uttar Pradesh”, notes Aylward. This is crucial to the global eradication effort as viral genomic sequencing has revealed repeated importation between northern India and southern Africa. Mass vaccination campaigns are also planned in Pakistan and Afghanistan. “Conflict is obviously the biggest problem in Afghanistan but only type 3 poliovirus is circulating there now; continued immunisations are happening during ‘days of tranquillity’, and local negotiations with all parties in the conflict to improve the access and safety for the vaccination teams are tireless”, adds Aylward. Polio in India is endemic in only some areas of Bihar and Uttar Pradesh where the bulk of recurrent or persistent transmission occurs in only 107 blocks (subdistrict units). “These are densely populated areas with a high birth rate, poor sanitation, frequent diarrhoeal episodes, and large migrant populations, so are logistically difficult to cover”, says Hamid Jafari, of WHO, the main technical advisor on the implementation of polio eradication to the Government of India. The first immunisations with the bOPV took place in northern India in January and early February, confirmed Jafari.
Polio eradication in India is a more daunting challenge because of the competition that any live polio vaccine faces from the plethora of other intestinal infections present in the population. “In northern India, vaccine coverage is very high, confirmed by serology studies showing greater than 99% immunity against type 1 poliovirus among infants, despite a huge monthly birth cohort. And yet, transmission of type 1—prioritised for eradication by the programme—is at a tipping-point. The programme is tantalisingly close to eradicating this serotype in India, but the virus has bounced back from very low case numbers before”, notes Nicholas Grassly (Imperial College, London, UK). “We know that we need to further understand the factors that are still allowing transmission to persist in these pockets and additional options to overcome those challenges”, agrees Jafari. Experts have recommended research studies, including assessment of mucosal immunity and the controversial additive role of the inactivated polio vaccine. Parallel improvements in sanitation, clean water supplies, and living conditions are being accelerated to reduce exposure to the virus.
Despite the challenges, Jafari reports that everyone involved is constantly urged on by knowing that the goal of eradication is achievable. “The current strategies have, in the past, stopped transmission of type 1 poliovirus for 16 months in western Uttar Pradesh and of type 3 in Bihar for 3 years consecutively. We know that this is feasible and doable”, he stresses. At the start of 2006, there were seven genetic clusters of type 1 virus circulating in India; this fell to three in 2008 and just one in 2009. “The ‘death’ of virus families is a strong indicator that transmission is declining”, he says.
All of this is happening against the backdrop of a new international commitment, firmed up at a special consultation with donor and infected countries in late-November, 2009, and endorsed by the WHO Executive Board in late January, to proceed with a new 2010—12 Programme of Work to finish the job of eradication”, explained Aylward. The Bill and Melinda Gates Foundation (Seattle, WA, USA), which has contributed more than $700 million to the global polio eradication effort “continues to be deeply committed through its financial resources, technical support, and the active engagement of our leadership”, Rajeev Venkayya, Director of Global Health Delivery at the Gates Foundation told TLID. Given what is at stake, he stresses that it is important that the best minds and diverse perspectives continue to be applied to this challenge.
Can global polio eradication be achieved? David Salisbury, Director of Immunisation at the UK Department of Health (London, UK) thinks the answer is yes. “I see Nigeria, Pakistan, and Afghanistan as logistic problems (different ones, for sure) but these could be solved. India is a different and more complex scientific challenge but I think it can be done. The time to interruption of transmission will be the outcome of resource inputs and political commitment”, he concluded.
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