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Polio Highlight

Basic Polio Facts

Fact sheet N°114 Rev.1
April 2013
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 223 reported cases in 2012. The reduction is the result of the global effort to eradicate the disease.
  • In 2013, 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. Failure to eradicate polio from these last remaining strongholds could result in as many as 200 000 new cases every year, within 10 years, all over the world.
  • In most countries, the global effort has expanded capacities to tackle other infectious diseases by building effective surveillance and immunization systems.

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 223 reported cases in 2012. In 2013, 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 GPEI was launched, the number of cases has fallen by over 99%. In 2013, only three countries in the world remain polio-endemic: Nigeria, Pakistan and Afghanistan.

In 1994, the WHO Region of the Americas was certified polio-free, followed by the WHO Western Pacific Region in 2000 and the WHO European Region in June 2002. Of the three types of wild poliovirus (type 1, type 2 and type 3), type 2 wild poliovirus transmission has been successfully stopped (since 1999).

More than 10 million people are today walking, who would otherwise have been paralysed. An estimated more than 1.5 million childhood deaths have been prevented, through the systematic administration of Vitamin A during polio immunization activities.

Opportunity and risks: an emergency approach

The strategies for polio eradication work when they are fully implemented. This is clearly demonstrated by India’s success in stopping polio in January 2011, in arguably the most technically-challenging place. However, failure to implement strategic approaches leads to ongoing transmission of the virus. Endemic transmission is continuing in Nigeria, Pakistan and Afghanistan. Failure to stop polio in these last remaining areas could result in as many as 200 000 new cases every year, within 10 years, all over the world.

Recognizing both the epidemiological opportunity and the significant risks of potential failure, the World Health Assembly in May 2012 adopted a resolution declaring the completion of polio eradication a programmatic emergency for global public health and called for the development of a comprehensive polio eradication and endgame strategy through 2018 to secure a lasting polio-free world.

Subsequently, the three remaining endemic countries launched national polio emergency action plans, overseen in each case by the respective head of state, and the partner agencies of the GPEI also moved their operations to an emergency footing, working under the auspices of the Global Emergency Action Plan 2012-2013. By the start of 2013, the impact of the emergency approaches is being seen, with the lowest number of reported cases in fewer districts of fewer countries than at any previous time.

Since then, the new Polio Eradication and Endgame Strategic Plan 2013-2018 has been developed, in consultation with polio-affected countries, stakeholders, donors, partners and national and international advisory bodies. The new Plan was presented at a Global Vaccine Summit in Abu Dhabi, United Arab Emirates, at the end of April 2013. It is the first plan to eradicate all types of polio disease simultaneously – both due to wild poliovirus and due to vaccine-derived polioviruses.

Global leaders and individual philanthropists signaled their confidence in the Plan by pledging three-quarters of the Plan’s projected US$5.5 billion cost over the six years. They also called upon additional donors to commit upfront the additional US$1.5 billion needed to secure a lasting polio-free world.

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


Last Updated on Monday, 13 January 2014 14:38

Aide Memoire – Types of Vaccine-derived Poliovirus (VDPV)


T
ypes of Vaccine-derived Poliovirus

 

There are three types of vaccine-derived poliovirus [2,3]:

1. Circulating vaccine-derived poliovirus (cVDPV)

On very rare occasions, if a population is seriously under-immunized, and other risks factors are present (crowding, poor hygiene and tropical climate) the probability that the Sabin viruses can mutate or recombine and change to VDPV exists, if there are enough susceptible children for the excreted vaccine-derived polioviruses to begin circulating in the community. These viruses are called circulating vaccine-derived polioviruses (cVDPV).

As with naturally occurring poliovirus, the only protection against cVDPV is full vaccination. Circulating VDPVs in the past have been rapidly stopped with 2–3 rounds of high-quality immunization campaigns. The solution is the same for all polio outbreaks: immunize every child several times with the oral vaccine to stop polio transmission, regardless of the origin of the virus.

2. Immunodeficiency-related vaccine-derived poliovirus (iVDPV)

Prolonged replication of vaccine-derived viruses has been observed in a small number of people with rare immune deficiency disorders (ej: B cell immunodeciencies). Because they are not able to mount an immune response, these people are not able to clear the intestinal vaccine virus infection, which is usually cleared within six to eight weeks. They therefore excrete immunodeficiency-related vaccine-derived polioviruses (iVDPVs) for prolonged periods.

The occurrence of iVDPVs is very rare. Only 42 cases have been documented worldwide. Of these, most stopped excretion within six months or died. Three people excreted the virus for more than 5 years.

3. Ambiguous vaccine-derived poliovirus (aVDPV)

Ambiguous vaccine-derived polioviruses (aVDPVs) are vaccine-derived polioviruses that are either isolated from people with no known immunodeficiency, or isolated from sewage whose ultimate source is unknown. Very little is known about them but to go into this classification, there has to be no more AFP cases related to VDPV in the community.

 
Last Updated on Thursday, 26 July 2012 06:30

Officially reported wild polio virus cases as of 03 Jul 2012

Total global cases in 2012: 88 (compared with 252 for the same period in 2011)
Total in endemic countries in 2012: 84 (compared with 226 for the same period in 2011)
Total in non-endemic countries in 2012: 4 (compared with 26 for the same period in 2011)

• Nigeria: 52 cases in 2012 (compared with 17 for the same period in 2011), onset of paralysis of most recent case: 06-Jun-12
• Pakistan: 22 cases in 2012 (compared with 58 for the same period in 2011), onset of paralysis of most recent case: 22-May-12
• Afghanistan: 10 cases in 2012 (compared with 8 for the same period in 2011), onset of paralysis of most recent case: 29-May-12
• Chad: 4 cases in 2012 (compared with 85 for the same period in 2011), onset of paralysis of most recent case: 11-May-12
• Niger: 0 case in 2012 (compared with 1 for the same period in 2011), onset of paralysis of most recent case: 22-Dec-11
• DRC: 0 case in 2012 (compared with 60 for the same period in 2011), onset of paralysis of most recent case: 20-Dec-11
• CAR: 0 case in 2012 (compared with 0 for the same period in 2011), onset of paralysis of most recent case: 08-Dec-11
• China: 0 case in 2012 (compared with 0 for the same period in 2011), onset of paralysis of most recent case: 09-Oct-11
• Guinea: 0 case in 2012 (compared with 1 for the same period in 2011), onset of paralysis of most recent case: 03-Aug-11
• Kenya: 0 case in 2012 (compared with 0 for the same period in 2011), onset of paralysis of most recent case: 30-Jul-11
• Côte d'Ivoire: 0 case in 2012 (compared with 11 for the same period in 2011), onset of paralysis of most recent case: 24-Jul-11
• Angola: 0 case in 2012 (compared with 4 for the same period in 2011), onset of paralysis of most recent case: 07-Jul-11
• Mali: 0 case in 2012 (compared with 4 for the same period in 2011), onset of paralysis of most recent case: 23-Jun-11
• Congo: 0 case in 2012 (compared with 1 for the same period in 2011), onset of paralysis of most recent case: 22-Jan-11
• Gabon: 0 case in 2012 (compared with 1 for the same period in 2011), onset of paralysis of most recent case: 15-Jan-11
• India: 0 case in 2012 (compared with 1 for the same period in 2011), onset of paralysis of most recent case: 13-Jan-11

By changing yourself, you can change the world!

During the polio management training in Afghanistan, participants agreed on a slogan and theme that expresses their spirit and sense of optimism for polio eradication in the country: “By changing yourself, you can change the world!”

Source: Wild Poliovirus Weekly Update 06-Jun-2012, World Health Organization

Last Updated on Friday, 08 June 2012 05:28

Programmatic Emergency:

The World Health Assembly (WHA) declared the completion of polio eradication a programmatic emergency for global public health. In total, 35 member states spoke to offer their strong support to the resolution, many highlighting the feasibility and opportunity of eradication in the near-term, but expressing concern at the ongoing funding gap that is threatening success.

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