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Polio is a viral infection that can result in permanent paralysis.

More than half of all cases are in children under age three but anyone can be affected. Poliovirus is spread by person-to-person contact, and contact with infected faeces or with secretions from the nose or mouth. The virus establishes itself in the intestines, from where it can enter the blood and invade the nervous system. In severe cases, the brainstem can be infected, leading to respiratory failure and death. As the virus multiplies it destroys nerve cells that activate muscles, particularly in the legs, so that these muscles no longer function.

There is no cure for polio and immunization is the only effective way to prevent the disease.

Since 1955, when the first effective polio vaccines were introduced, the disease has been practically eliminated as a public health problem in the industrialized countries. In 1988 the World Health Assembly resolved to eradicate polio globally by the end of the year 2000.

In 12 years, thanks to the efforts of national governments working with WHO, Rotary International, UNICEF and other partners, the number of reported cases fell markedly from an estimated 350,000 to approximately 3,500 in 2000, according to WHO.

Today, polio is within sight of eradication worldwide. Large parts of the world are polio-free, including the WHO Regions of the Americas, Western Pacific, and Europe. However, the fragility of the progress is reflected by recent outbreaks that have occurred where immunization programmes have broken down because of war or other disruption. During 2000, reservoirs of poliovirus infection in South Asia and West/Central Africa are targeted for accelerated eradication activities.

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At a glance

Vaccine-preventable disease statistics

Glossaire des infections a prévention vaccinale

'Traditional' or 'basic' vaccines

  • Polio
  • Diphtheria
  • Pertussis
  • Tetanus
  • Measles

Under-used vaccines

  • Haemophilus influenzae b (Hib)
  • Hepatitis B
  • Yellow fever

Vaccines that are expected to be available shortly

  • Pneumococcus (Streptococcus pneumoniae)
  • Rotavirus
  • Meningococcal A/C conjugate

Other vaccines

  • Japanese encephalitis

Vaccines for which more research is needed

  • Malaria
  • HIV
  • Tuberculosis


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