Immunization

Eradicating polio

GOAL: To assist governments in their efforts to immunize every child against polio until polio transmission has stopped, so that the world can be certified polio-free.

STATUS:  Since the momentous launch of the Global Polio Eradication Initiative in 1988 during the World Health Assembly in Geneva, nearly five million children, who otherwise would have been paralyzed and incapacitated by polio, are walking, able and symptoms-free. The number of polio cases reported annually has decreased by 99% – from 350,000 in 1988 to 2,000 cases in 2006. This rapid success has been achieved through a global campaign to immunize every child under five. Since the late nineties, the polio vaccine has been delivered to children in endemic countries through mass immunization campaigns, known as National Immunization Days (NIDs).

Global Polio Eradication Initiative
UNICEF is working to protect all children from polio by immunizing every child until the disease is eradicated.  Along with national governments, the World Health Organization, Rotary International and the U.S. Centers for Disease Control and Prevention, we are a spearheading partner in the Global Polio Eradication Initiative (GPEI) – the largest and most far-reaching public health initiative of all time.  This global initiative has a single goal – a polio-free world for all children.

The year 2006 began with the confirmation that wild poliovirus (WPV) transmission had been interrupted in Egypt and Niger. In Nigeria, Afghanistan, Pakistan and India, the endemic polio reservoirs have been reduced to specific geographic areas and limited populations. These four remaining endemic countries accounted for almost 94% of all new polio cases (1,872 cases out of a total of 2,000 cases globally) in 2006. Through the review of epidemiological data and coverage reports, experts have identified the reasons for the continued transmission of wild polio virus in these four endemic countries. Each endemic country offers a unique set of challenges which require country-specific solutions. These challenges include intense virus circulation in northern India, security problems in Afghanistan and Pakistan and low immunization coverage in northern Nigeria due to the lack of quality operations.

The use of monovalent oral polio vaccine type 1 (mOPV1) in 2005 and 2006 significantly reduced the transmission of type 1 poliovirus and for the first time ever, worldwide, there were more cases of poliovirus type 3 (P3) than poliovirus type 1 (P1).  The mOPVs are a potent additional tool in eradicating WPV in the remaining four endemic countries. Also, laboratory procedures to confirm WPV have become faster, allowing rapid immunization responses.

Within the partnership, UNICEF continues to focus on specific programmatic components in which the agency has a comparative advatage. In 2006, UNICEF procured over 2 billion doses of OPV for SIAs in 30 countries; supported the delivery of other services such as Vitamin A with polio supplementary activities; and provided programmatic assistance to national governments in planning, monitoring, and evaluating all aspects of immunization activities to interrupt polio transmission in polio-affected countries and to maintain polio-free status elsewhere.

In 2007, the four endemic countries (Afghanistan, India, Nigeria and Pakistan) and the six re-infected countries (Angola, Chad, Democratic Republic of Congo, Niger, Myanmar and Somalia) continued to report cases. Of the total 471 cases of wild poliovirus (WPV) reported as of September 11, 2007, 407 were from the endemic countries and 64 were from the re-infected countries. The total number of cases reported in 2007 is less than half of the total reported for the same period in 2006 (1,228 cases).

Stakeholder Consultation on Polio Eradication
The Consultation was held on 28 February 2007 at the WHO Headquarters in Geneva, Switzerland. It reviewed the collective capacity of the partnership to meet the remaining operational and financial challenges for polio eradication. The Consultation outlined specific milestones which must be met in order to ensure that the levels of vaccination coverage and child immunity in areas with endemic transmission are raised within 12 months - and then sustained for as long as needed - to the same levels as those that stopped the disease in the polio-free areas of the four endemic countries.  The milestones will focus on such operational aspects as population immunity, cross-ministry support and oversight, polio campaign quality, social mobilization and community engagement.   While the focus of the high-level Consultation on polio in Geneva was on polio eradication in the four remaining countries that have never stopped transmission, delegates highlighted the ongoing risk of the international spread of polio.

Milestones for an Intensified Polio Eradication Effort

1. Endemic Countries: Reduction in Polio-Infected Districts
   • by end-2007 there should be a 50% reduction in the number of polio-infected districts relative to 2006.
   • by end-2008 polio transmission should be interrupted or there should be at least a further 50% reduction in the number of infected districts relative to 2007.
2. Endemic Countries: Increase in Protection Against Polio in Infected Districts
   • by end-2007 the level of immunity against polio among children aged 6-35 months in infected districts should be at least at the level in polio-free districts.
   • by end-2008 the level of polio immunity among children aged 6-35 months in infected districts should have been at least as high as in polio-free districts, for at least 12 months.
3. Reinfected Countries: Rapid Cessation of New Polio Outbreaks
   • by end-2007, countries reinfected in 2006 will have implemented appropriate response activities13 and interrupted transmission of the imported poliovirus.
   • by end-2008, any country reinfected in 2007 will have implemented response activities and interrupted transmission of the imported poliovirus.
4. International Stakeholders: Closure of the Financing Gap
   • by mid-2007 sufficient funding will have been pledged to finance all eradication activities planned through end-2007.
   • by end-2007 sufficient funding will have been pledged to finance all eradication activities planned through end-2008.

Stakeholders can monitor progress towards the milestones and activities of the intensified eradication effort on the GPEI website, and in GPEI publications. In each endemic country, activities will be monitored and guided every 4-6 months by the polio technical advisory body (the Expert Review Committee in Nigeria; the Technical Advisory Group in Afghanistan and Pakistan; and the India Expert Advisory Group). At the international level, activities will be monitored by the Advisory Committee on Polio Eradication every 6 months (with a face-to-face meeting every 12 months) and by regional advisory committees each year. [See also The Case for Completing Polio Eradication, WHO, 2007]

Challenges
The remaining challenges to the achievement of a polio-free world include:

• Rapidly overcoming the remaining operational challenges to reaching every child in the four endemic areas of Nigeria, India, Pakistan and Afghanistan.
• Rapidly making available the necessary financial resources to fully implement polio eradication strategies.
• Rapidly responding to outbreaks in the remaining re-infected countries, and minimizing the risk and consequences of further international spread.
• Increasing polio vaccination coverage through routine immunization services.