Chapter 4: Polio Eradication: the final challenge
Polio Eradication: the final challenge
As a result of the Global Polio Eradication Initiative, one of the largest public health efforts in history, the number of children paralysed by this devastating disease every year has fallen from over 350 000 in 1988 to as few as 1900 in 2003; the number of endemic countries has fallen from over 125 to seven. This chapter records the final phase of the campaign to eradicate one of the oldest known diseases. The vision of a polio-free world is now within reach.
In 1962, just 12 months after Albert Sabin's widely hailed oral polio vaccine (OPV) was licensed in most industrialized countries, Cuba began using the vaccine in a series of nationwide polio campaigns. Shortly thereafter, indigenous wild poliovirus transmission had been interrupted. In other words, no Cuban child would ever again suffer this devastating disease as the result of a Cuban poliovirus. Seldom, if ever, had a new health technology been fully exploited so successfully and so early in its lifespan, to the benefit of so many people. Few countries were to experience such early successes, however, as polio continued to paralyse permanently half a million people every year -- even by the 1990s between 10 and 20 million people who had survived the acute illness were living with its debilitating and often painful consequences. For Sabin, however, Cuba's experience with mass campaigns had reaffirmed his conviction that polioviruses could be eradicated so completely that future generations would know polio paralysis only through history books. Sabin's way of shaping that future without polio was to donate his vaccine to the World Health Organization so that it might be made available to all peoples, everywhere.
Forty years later, the world is on the verge of realizing Sabin's global vision of a future without polio. Through an extraordinary 15-year international effort, indigenous polioviruses have now been eliminated from all but seven countries, down from over 125 when the initiative began (1) (see Figure 4.1). This progress is the result of a unique partnership forged between governments, international agencies, humanitarian organizations and the private sector to take up three key challenges to reaching all children, everywhere: effective engagement of political leaders, adequate financing, and sufficient human resources. Through this partnership, over 10 million volunteers immunized 575 million children against polio in 93 of the lowest-income countries in the world in the year 2001 alone. This experience, and the prospects for the completion of polio eradication, provide insights for scaling up access to other health interventions, a process that will be essential to achieving ambitious national and international health targets such as those adopted in the Millennium Development Goals (2).
Figure 4.1
Box 4.1 Progress towards polio eradication in the Eastern Mediterranean
All countries of the Eastern Mediterranean Region are rapidly progressing towards the eradication of poliomyelitis. The number of cases has decreased relatively regularly, as shown by the well-developed and efficient surveillance system. By the end of 2002, poliovirus transmission had been interrupted in 18 countries of the region for more than three years; in addition, Sudan has not reported a single polio case since April 2001. During 2002, 110 confirmed cases of polio were reported from only four countries (Pakistan: 90; Afghanistan: 10; Egypt: 7; and Somalia: 3). During the first eight months of 2003, 61 cases were reported (Pakistan: 57; Afghanistan: 2; and Egypt: 1); a further case, in Lebanon, proved to be imported and genetically linked to the virus strains from India.
Intensified national immunization days (NIDs) are continuing in 2003, with technical support from WHO, both in endemic countries (Afghanistan, Egypt, Pakistan and Somalia) and in Sudan which was recently declared polio-free. All these countries conduct more than two NIDs and one or more rounds of sub-national immunization days (SNIDs) in high-risk districts each year, reaching all children through house-to-house immunization. Acute flaccid paralysis (AFP) surveillance continued to improve throughout the region. The non-polio AFP rate has further increased in 2003 to reach 2.39 per 100 000 children under 15 years of age, while stool specimen collection has reached 90%.
As the polio eradication initiative moves into its final phase, technical advisory groups for the priority countries regularly review the epidemiological situation and national plans and provide technical advice. In addition, a regional technical advisory group was established to provide leadership for eradication activities in the remaining polio-endemic countries and to advise Member States on other technical issues. Increasing attention is being given to the laboratory containment of wild poliovirus, the certification of polio eradication and the development of post-certification immunization policy.
National containment coordinators have been nominated in 19 of the 23 countries of the region, 16 of which have also established national containment committees. By the end of 2002, 18 countries had prepared a national containment plan; three of the remaining five countries still have ongoing virus transmission. The first containment phase has been successfully completed in seven countries and is currently being implemented in another 11.
All countries of the region except Somalia have established National Certification Committees (NCCs) with appropriate membership. Eighteen countries with no viral circulation have submitted reports and national documentation to the Regional Certification Committee (RCC), which has already reviewed 15 of these reports and provided appropriate feedback. The RCC is also reviewing annual updates provided by countries whose initial reports were satisfactory. These annual updates will be submitted annually until regional certification is achieved.
Despite the significant achievements in remaining endemic areas, the eradication programme still faces a number of challenges and constraints that must be overcome to reach the final goal. The main focus now is Pakistan, where several outbreaks occurred during 2002--2003. It seems that the youngest children in tribal and conservative populations are likely to be missed if the vaccination team does not include a woman. In order to overcome these difficulties, the emphasis is on enlisting federal, provincial and local political leaders and expanding the SNIDs to target all transmission zones. New international staff are being mobilized in districts with no previously assigned consultants, to help provide the needed technical support to ensure high-quality performance in surveillance in all areas.
Box 4.2 Responding to the challenge of polio eradication in South-East Asia
In 2002, the global goal of polio eradication was jeopardized as India suffered the largest outbreak in recent history: 1600 cases were reported that year, a fivefold increase over 2001. As the epidemic spread into Indian states which had finally become polio-free in recent years, the number of infected districts more than doubled from 63 in 2001 to 159. Because of India's long borders with Bangladesh and Nepal, the epidemic also threatened these polio-free countries. By the end of 2002, the South-East Asia Region accounted for 84% of the global polio burden. Since then, however, a massive national and international response has again brought polio to the brink of elimination in the most populous WHO region.
By the end of 2000, 9 of the 10 WHO Member States in the South-East Asia Region and 35 of India's 37 states had interrupted wild poliovirus transmission as part of the global eradication effort. In addition to Bangladesh and Nepal, Myanmar has been polio-free since 2000; Bhutan, the Democratic People's Republic of Korea, Indonesia, Maldives, Sri Lanka and Thailand all stopped indigenous transmission prior to 1999. This progress is the result of a regionally coordinated, data-driven programme that began in the early 1990s and through which National Immunization Days have reached over 200 million children, often synchronized across Member States and supported by regional bodies such as the South Asian Association for Regional Cooperation. Strong polio surveillance and a regional network of 17 high-quality laboratories have guided the effort and confirmed these achievements.
Investigations into the 2002 epidemic demonstrated that a combination of low routine immunization coverage and an insufficient scale, number and quality of polio campaigns had led to a rapid accumulation of susceptible children, especially in the state of Uttar Pradesh. In response, political oversight of the programme was markedly increased, the number of polio campaigns was raised to six per year, and additional efforts were made to reach children in minority populations. Consequently, by the end of September 2003, polio was at its lowest level in history (132 cases) and there was again the real possibility of forever eliminating this devastating disease from South-East Asia by 2005.