Fact sheet N°114
February 2012
Original article:http://www.who.int/mediacentre/factsheets/fs114/en/index.html

Key facts

• Polio (poliomyelitis) mainly affects children under five years of age.
• One in 200 infections leads to irreversible paralysis. 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 1 352 reported cases in 2010. The reduction is the result of the global effort to eradicate the disease.
• In 2012, only three countries (Afghanistan, Nigeria and Pakistan) remain polio-endemic, down from more than 125 in 1988.
• Persistent pockets of polio transmission in 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. In 2009-2010, 23 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.
• Success hinges on financing the 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 1352 reported cases in 2010. In 2012, only parts of three countries in the world remain endemic for the disease - the smallest geographic area in history - and case numbers of wild poliovirus type 3 are down to lowest-ever levels.

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 WHO, Rotary International, the US Centers for Disease Control and Prevention (CDC) and the United Nations Children’s Fund (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, since the Global Polio Eradication Initiative was launched, the number of cases has fallen by over 99%. In 2012, only three countries in the world remain polio-endemic. Persistent pockets of polio transmission in northern Nigeria and along the border between Afghanistan and Pakistan are key epidemiological challenges.

In 1994, the 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 2010, the European Region suffered its first importation of polio after certification. In 2011, the WHO Western Pacific Region also suffered an importation of poliovirus.

In 2009, more than 361 million children were immunized in 40 countries during 273 supplementary immunization activities (SIAs). Globally, polio surveillance is at historical highs, as represented by the timely detection of cases of acute flaccid paralysis.

Objectives

The objectives of the Global Polio Eradication Initiative are:

• to interrupt transmission of wild poliovirus as soon as possible;
• to achieve certification of global polio eradication;
• to contribute to health systems development and strengthen 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:

• there are at least three years of zero polio cases due to wild poliovirus;
• disease surveillance efforts in countries meet international standards; and
• 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 Independent Monitoring Board (IMB) evaluates on a quarterly basis the progress towards each of the major milestones of the Global Polio Eradication Initiative Strategic Plan 2010-2012, determine the impact of any 'mid-course corrections' that are deemed necessary, and advise on additional measures when appropriate.

Coalition

The Global Polio Eradication Initiative (GPEI) is spearheaded by WHO, Rotary International, CDC and UNICEF. The eradication of polio is about equity in health and the moral imperative of reaching every child with an available health intervention.

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 the Global Poverty Project) and corporate partners (e.g. Sanofi Pasteur and Wyeth). Volunteers in developing countries also play a key role: 20 million people have participated in mass immunization campaigns.

Priorities for polio eradication

As long as a single child remains infected with polio, children in all countries are at risk of contracting the disease.

To stop transmission of the wild poliovirus and optimize the benefits of polio eradication, the global priorities are:

Stopping wild poliovirus transmission in endemic countries

Polio today is more geographically restricted than ever before. The highest priority is reaching all children during SIAs in the four countries which have never stopped transmission of polio. To succeed, high levels of political commitment must be maintained at national, state/provincial and district levels. In 2010, a new strategic plan was launched, based on lessons learned in the past years and an independent evaluation of the major barriers to stopping polio transmission. This strategic plan is based on district-specific planning to address the unique challenges of each of the infected areas, fully exploiting new tools such as bivalent oral polio vaccine and strengthening health systems.

Putting an end to re-established transmission

Three countries - Angola, Chad and the Democratic Republic of the Congo - are classified as having 're-established transmission' because they have had ongoing transmission for over 12 months. These countries are treated with the same level of priority as the endemic countries. In early 2011, all three countries initiated emergency action plans to address the situation and fill operational gaps.

Preventing new outbreaks

Poliovirus has a habit of finding pockets of inadequately vaccinated children. As China, Congo, the Russian Federation and Tajikistan have learned, the poliovirus does not respect national borders. To minimize the risk of outbreaks from importation, countries must maintain high population immunity levels.

Closing the funding gap

Substantial financial resources are required to support polio eradication. However, in addition to the obvious humanitarian benefits, economic modelling has demonstrated the financial benefits of polio eradication to be at least US$ 40-50 billion. Success in carrying out the necessary vaccination campaigns and surveillance hinges on sufficient funds from financial stakeholders.

Impact of the initiative

More than eight million people who would otherwise have been paralysed are walking today because they have been immunized against polio since the initiative began in 1988.

By preventing a debilitating disease, the Global Polio Eradication Initiative is helping 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 health emergencies such as the 2010 floods in Pakistan and the 2011 drought in the Horn of Africa.

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 that will benefit all people equally, no matter where they live. Economic modelling has found that the eradication of polio in the next five years would save at least US$ 40-50 billion, mostly in low-income countries