Polio has almost been defeated, but has not yet been eradicated. Since 1988, cases of wild poliovirus in the world have decreased by over 99%, going from over 350 thousand per year to circulation now limited to two endemic countries. The World Health Organization (WHO) remembered this in 2025. On World Polio Day, October 24, the data shows the progress of vaccination but also difficulties that still remain to be overcome.
What is polio
Poliomyelitis is a serious disease caused by three types of poliovirus (1,2 and 3), belonging to the enterovirus genus. It affects the nervous system, causing the destruction of neural cells and causing paralysis which, in the most serious cases, can become total. In most cases, the most devastating effects affect the muscles of the upper and lower limbs. The latter tend to lose muscle tone and become flaccid (flaccid paralysis). If the infection extends to both arms and legs, the patient may become quadriplegic. In the bulbar form, the most serious, the viral agent paralyzes the muscles innervated by the cranial nerves, reducing the ability to breathe, swallow and speak.
An updated global estimate is missing
There is no updated and univocal global estimate of all the people who today live with the effects of polio. A scientific review published in 2015 estimated between 15 and 20 million people affected by post-polio syndrome, a condition that can manifest itself many years after the infection, with new muscle weakness, tiredness and motor difficulties (scientific study on PubMed). This figure, however, concerns post-polio syndrome and does not represent the updated number of all people who have had the disease.
According to the WHO, polio mainly affects children under five years of age. About one in 200 infections causes irreversible paralysis; Among paralyzed people, 5-10% may die when their breathing muscles are compromised.
Vaccination progress
By 1988, when the Global Polio Eradication Initiative was launched, the disease was endemic in more than 125 countries. Since then, vaccination and international campaigns have reduced cases by more than 99%. According to the US Centers for Disease Control and Prevention (CDC), immunization efforts have helped prevent approximately 20 million cases of paralysis in children (CDC, Global Vaccination Program). In 1988, the disease affected 350 thousand children. And 3 billion children have been vaccinated in 30 years.
Furthermore, two of the three serotypes of wild poliovirus have been eradicated: type 2, in 2015, and type 3, in 2019. Type 1 remains, still endemic in Afghanistan and Pakistan, as confirmed by the WHO.
For polio, whose path towards eradication continues, Sage reiterated the progressive elimination of oral vaccines by introducing the possibility of reducing doses in low-risk contexts. Countries where three doses of inactive vaccine (IPV) are administered in the first year of life may reduce the doses of bivalent oral vaccine (bOPV) from three to two. However, in some areas the spread of the wild virus continues, while in several African countries the circulation of vaccine-derived polyviruses continues, linked to insufficient vaccination coverage.
Afghanistan and Pakistan, the cases of 2026
But the challenge is still open. According to the Global Polio Eradication Initiative (GPEI) bulletin updated as of October 21, 2026, Afghanistan has recorded 42 cases of wild poliovirus since the beginning of the year, double the 21 reported in all of 2025. In Pakistan, the latest national update available as of October 5 reported six cases in 2026.
However, the problem does not only concern these two countries. The GPEI bulletin also reports vaccine-derived poliovirus outbreaks in several states, including Chad, the Democratic Republic of Congo, Nigeria, South Sudan and Togo. These outbreaks can develop when the virus circulates for a long time in communities with insufficient vaccination coverage. The priority therefore remains to reach all children, especially in the most difficult to reach areas. There is still no definitive cure: vaccination remains the fundamental tool for preventing it. The WHO emphasizes that as long as the virus continues to circulate, even countries that have eliminated transmission will remain exposed to the risk of importation and new outbreaks.
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