Poliomyelitis
Polio (poliomyelitis) mainly affects children under five years of age.
One in 200 infections leads to irreversible paralysis (usually in the legs). Among those paralysed, 5% to 10% die when their breathing muscles become immobilized.
Polio cases have decreased by over 99% since 1988, from an estimated 350 000 cases then, to 1997 reported cases in 2006. The reduction is the result of the global effort to eradicate the disease.
In 2008, only four countries in the world remain polio-endemic, down from more than 125 in 1988. The remaining countries are Afghanistan, India, Nigeria and Pakistan.
Persistent pockets of polio transmission in northern India, northern Nigeria and the border between Afghanistan and Pakistan are the current focus of the polio eradication initiative.
As long as a single child remains infected, children in all countries are at risk of contracting polio. Between 2003 and 2005, 25 previously polio-free countries were re-infected due to imports of the virus.
In most countries, the global effort has expanded capacities to tackle other infectious diseases by building effective surveillance and immunization systems. Knowledge of the poliovirus has expanded with aggressive research carried out under the eradication effort.
Success for the effort hinges on closing a substantial funding gap to finance next steps of the global eradication initiative.
Polio and its symptoms
Polio is a highly infectious disease caused by a virus. It invades the nervous system, and can cause total paralysis in a matter of hours. The virus enters the body through the mouth and multiplies in the intestine. Initial symptoms are fever, fatigue, headache, vomiting, stiffness in the neck and pain in the limbs. One in 200 infections leads to irreversible paralysis (usually in the legs). Among those paralysed, 5% to 10% die when their breathing muscles become immobilized.
People most at risk
Polio mainly affects children under five years of age.
Prevention
There is no cure for polio, it can only be prevented. Polio vaccine, given multiple times, can protect a child for life.
Global caseload
Polio cases have decreased by over 99% since 1988, from an estimated 350 000 cases in more than 125 endemic countries then, to 1997 reported cases in 2006. In 2008, only parts of four countries in the world remain endemic for the disease - the smallest geographic area in history.
The Global Polio Eradication Initiative
Launch
In 1988, the forty-first World Health Assembly, consisting then of delegates from 166 Member States, adopted a resolution for the worldwide eradication of polio. It marked the launch of the Global Polio Eradication Initiative, spearheaded by the World Health Organization (WHO), Rotary International, the US Centers for Disease Control and Prevention (CDC) and UNICEF. This followed the certification of the eradication of smallpox in 1980, progress during the 1980s towards elimination of the poliovirus in the Americas, and Rotary International’s commitment to raise funds to protect all children from the disease.
Progress
Overall, in the 20 years since the Global Polio Eradication Initiative was launched, the number of cases has fallen by over 99%. In 2008, only four countries in the world remain polio-endemic.
In 1994, the World Health Organization (WHO) Region of the Americas (36 countries) was certified polio-free, followed by the WHO Western Pacific Region (37 countries and areas including China) in 2000 and the WHO European Region (51 countries) in June 2002.
In 2007, more than 400 million children were immunized in 27 countries during 164 supplementary immunization activities (SIAs). Globally, polio surveillance is at historical highs, as represented by the timely detection of cases of acute flaccid paralysis.
Persistent pockets of polio transmission in northern India, northern Nigeria and the border between Afghanistan and Pakistan are key epidemiological challenges.
Objectives
The objectives of the Global Polio Eradication Initiative are:
To interrupt transmission of the wild poliovirus as soon as possible;
To achieve certification of global polio eradication;
To contribute to health systems development and strengthening routine immunization and surveillance for communicable diseases in a systematic way.
Strategies
There are four core strategies to stop transmission of the wild poliovirus in areas that are affected by the disease or considered at high risk of re-infection:
high infant immunization coverage with four doses of oral poliovirus vaccine (OPV) in the first year of life;
supplementary doses of OPV to all children under five years of age during SIAs;
surveillance for wild poliovirus through reporting and laboratory testing of all acute flaccid paralysis (AFP) cases among children under fifteen years of age;
targeted “mop-up” campaigns once wild poliovirus transmission is limited to a specific focal area.
Before a WHO region can be certified polio-free, three conditions must be satisfied: (a) there are at least three years of zero polio cases due to wild poliovirus; (b) disease surveillance efforts in countries meet international standards; and (c) each country must illustrate the capacity to detect, report and respond to “imported” polio cases. Laboratory stocks must be contained and safe management of the wild virus in inactivated polio vaccine (IPV) manufacturing sites must be assured before the world can be certified polio-free.
The Advisory Committee on Polio Eradication, the independent, technical body providing strategic guidance to the Global Polio Eradication Initiative, is overseeing a programme of research and consensus-building that will lead to the development of post-eradication polio immunization policy options, which will be considered by the World Health Assembly.
Coalition
The Global Polio Eradication Initiative (GPEI) is spearheaded by WHO, Rotary International, the US Centers for Disease Control and Prevention (CDC) and the United Nations Children’s Fund (UNICEF).
The polio eradication coalition includes governments of countries affected by polio; private sector foundations (e.g. United Nations Foundation, Bill & Melinda Gates Foundation); development banks (e.g. the World Bank); donor governments (e.g. Australia, Austria, Belgium, Canada, Denmark, Finland, France, Germany, Iceland, Ireland, Italy, Japan, Luxembourg, Malaysia, Monaco, the Netherlands, New Zealand, Norway, Oman, Portugal, Qatar, the Republic of Korea, the Russian Federation, Saudi Arabia, Spain, Sweden, Switzerland, Turkey, United Arab Emirates, the United Kingdom and the United States of America); the European Commission; humanitarian and nongovernmental organizations (e.g. the International Red Cross and Red Crescent societies) and corporate partners (e.g. Sanofi Pasteur, De Beers and Wyeth). Volunteers in developing countries also play a key role: 20 million people have participated in mass immunization campaigns.
Countries at risk
As long as a single child remains infected with polio, children in all countries are at risk of contracting the disease. The poliovirus can easily be imported into a polio-free country and can spread rapidly among unimmunised populations. Between 2003 and 2005, 25 previously polio-free countries were re-infected due to importations.
The four polio-endemic countries are Afghanistan, India, Nigeria and Pakistan.
Priorities for polio eradication
To stop transmission of the wild poliovirus and optimize the benefits of polio eradication, the global priorities are:
Closing the funding gap: Substantial external financial resources are required to support the efforts of endemic countries to eradicate polio. Economic modelling in 2007 demonstrated the financial and humanitarian benefits of polio eradication. Success in carrying out the necessary vaccination campaigns and surveillance hinges on sufficient funds being made available by the financial stakeholders.
Stopping wild poliovirus transmission in endemic countries: Polio is today more geographically restricted than ever before. The highest priority is reaching all children during SIAs in the remaining four endemic countries. To succeed, high levels of political commitment must be maintained at national, state/provincial and district levels. In 2007 an intensified effort to eradicate polio occurred in each of these four countries, with tailored eradication approaches to address the unique challenges of each of the infected areas. Efforts fully exploited new monovalent vaccines and diagnostics that are significantly more effective in detecting and stopping polio transmission.
IMPACT OF THE INITIATIVE
The Global Polio Eradication Initiative was launched in 1988. More than five million people who would otherwise have been paralysed are today walking because they have been immunized against polio since the initiative began.
By preventing a debilitating disease, the Global Polio Eradication Initiative is helping to reduce poverty, and is giving children and their families a greater chance of leading healthy and productive lives.
By establishing the capacity to access children everywhere, more than two billion children worldwide have been immunized during SIAs, demonstrating that well-planned health interventions can reach even the most remote, conflict-affected or poorest areas.
Planning for SIAs provides key demographic data – “finding” children in remote villages and households for the first time, and "mapping" their location for future health services.
In most countries, the Global Polio Eradication Initiative has expanded the capacity to tackle other infectious diseases, such as avian influenza or Ebola, by building effective disease-reporting and surveillance systems, training local epidemiologists and establishing a global laboratory network. This capacity has also been deployed in post-disaster health emergencies such as the aftermath of the 2004 tsunami in south-east Asia.
Routine immunization services have been strengthened by bolstering the cold chain, transport and communications systems for immunization. Improving these services helped to lay the groundwork for highly successful measles vaccination campaigns that have saved millions of young lives.
Vitamin A is often administered during polio SIAs. Since 1988, more than 1.2 million childhood deaths have been prevented through provision of vitamin A during polio SIAs.
On average, one in every 250 people in a country has been involved in polio immunization campaigns. More than 20 million health workers and volunteers have been trained to deliver OPV and vitamin A, fostering a culture of disease prevention.
Through the synchronization of SIAs, many countries have established a new mechanism for coordinating major cross-border health initiatives aimed at reaching all people – a model for regional and international cooperation for health.
Future benefits of polio eradication
Once polio is eradicated, the world can celebrate the delivery of a major global public good – something that will equally benefit all people, no matter where they live. Economic modelling published in 2007 established that significant financial benefits will also accrue from eradication.