Eradicating Polio
Polio is a virus that can paralyse children for life. Vaccines have wiped it out in almost every country, and cases have dropped by more than 99 percent since 1988. But the virus still survives in parts of Afghanistan and Pakistan, where fighting and mistrust keep some children from being vaccinated. The vaccine drops used in many campaigns contain a weakened live virus that can, in rare cases and where few people are vaccinated, change back into a dangerous form. To finish the job, health workers must reach every last child and eventually replace the live-virus vaccine.
Open in the interactive tree →The Global Polio Eradication Initiative began in 1988, when an estimated 350,000 people a year were paralysed in more than 125 countries. Wild poliovirus type 2 was declared eradicated in 2015 and type 3 in 2019, and the African region was certified wild-polio-free in 2020. Wild type 1 persists in parts of Afghanistan and Pakistan, and the weakened live virus in oral vaccine can, where few children are vaccinated, change back into a form that again paralyses.
As of now
According to WHO data as of 5 October 2026, wild poliovirus type 1 paralysed 89 people in 2024 (66 in Pakistan, 23 in Afghanistan) and 47 in 2025 (27 and 20); in 2026 there were 40 cases by 6 October, 35 of them in Afghanistan, where transmission has shifted. Vaccine-derived type 2 virus paralysed 211 people in 2025 and 132 in 2026 up to early October. In July 2024 the Polio Oversight Board moved the targets to the end of 2027 for wild virus and the end of 2029 for type 2 variant virus, and in October 2024 announced a budget of 6.9 billion US dollars for 2022-2029 with 2.4 billion still missing at that time. The improved vaccine nOPV2, prequalified by WHO in December 2023 after nearly 1 billion doses, is estimated to be 80 percent less likely to start new variant outbreaks.
What is missing
- Safe, trusted access to every child in conflict-hit and mistrustful communities in Pakistan and Afghanistan
- Ways to find the last infections early, in paralysis reports and in sewage
- An end to outbreaks of vaccine-derived virus and a safe exit from the live oral vaccine
- Full funding for the extended 2022-2029 plan
Becomes possible once solved
- No child is paralysed by polio anywhere in the world
- Routine polio vaccination can eventually stop, freeing money and health workers for other care
- A second human disease is ended after smallpox
Open steps
- Vaccinating the Last Children Against Polio Medium AI leverageVaccinate every child in insecure or distrustful areas of Pakistan and Afghanistan, where by 11 September 2026 three of Pakistan's four cases of the year came from one division in which security problems have prevented regular vaccination since 2025.
- Ending Vaccine-Derived Polio Outbreaks Low AI leverageStop the spread of vaccine-derived poliovirus, mostly type 2, with the more stable nOPV2 vaccine (nearly 1 billion doses by January 2024) and better routine vaccination.
- Finding the Last Polio Infections Medium AI leverageDetect poliovirus quickly through reports of sudden paralysis and sewage testing; a 2022 paralytic case and positive sewage samples in New York showed that virus can spread unnoticed even in rich countries.
- A Safe Exit from Live Polio Vaccine Low AI leveragePlan and carry out the end of live oral polio vaccine once wild virus is gone, with enough protection from injected vaccine that no weakened virus is left circulating; the plan is to stop wild type 1 vaccination one year after certification.
- Polio Eradication Funding and Political Will Low AI leverageClose the funding gap of the extended 2022-2029 plan (6.9 billion US dollars, of which 2.4 billion were still missing in October 2024) and keep governments, donors and local leaders committed.
Where today's AI could help
Medium AI leverage. AI can map unvaccinated settlements and flag outbreak risk from surveillance data, but access, security, trust and money, decided in the field and in politics, are the hard limits.
- Find unmapped settlements and missed children from satellite images
- Forecast where under-vaccinated groups and outbreaks are most likely
- Compare virus genome sequences to trace where an outbreak began
Shown so far
- Nigeria, 2013-2020: satellite imagery, machine learning and community mapping produced settlement outlines and population estimates in 10 northern states, and planners used them to route vaccination teams; Nigeria was certified free of wild polio. source
Prerequisites
- World Health Organization1948WHO and partners run the global campaign.
- Polio Vaccines1955Both vaccines exist and have cut cases by over 99 percent.
- Smallpox Eradicated1980Smallpox is the only human disease ended so far, and the model.
Unlocks
- A Polio-Free World2030s?Needs the last wild virus and all vaccine-derived outbreaks stopped.