epidemiology

Last reviewed 01/2018

The Disease mainly affects children under five years of age (1).

According to the WHO statistics, the number of polio cases have decreased from an estimated 350 000 cases in 1988 to 223 reported cases in 2012 (over 99%) (1).

  • in 2013, only three countries (Afghanistan, Nigeria and Pakistan) remain polio-endemic, down from more than 125 in 1988.
    • 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 (2)

In the temperate climates a peak of the infection commonly occurs in the summer months while in the tropics there is no seasonal pattern (2)
When the infection is endemic, the paralytic disease is caused by naturally occurring poliovirus - 'wild virus' (3)

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