The global health body has warned that wild poliovirus transmission continues in the only two endemic countries, with vaccination gaps and cross-border challenges delaying eradication efforts worldwide.

The World Health Organisation has extended its declaration that the international spread of poliovirus remains a public health emergency of international concern for another three months, citing ongoing wild poliovirus transmission in Afghanistan and Pakistan.

The decision followed the 45th meeting of the WHO’s Emergency Committee under the International Health Regulations, convened in May and announced on 25 August 2026. Committee members unanimously concluded that the risk of international spread continues to meet the criteria for a public health emergency of international concern, or PHEIC, while determining that the situation does not amount to a pandemic emergency.

Afghanistan and Pakistan remain the world’s only countries with endemic transmission of wild poliovirus type 1, known as WPV1. Since the committee’s previous meeting in January, 16 new WPV1 cases were reported in the two countries – 14 in Afghanistan and two in Pakistan. Of Afghanistan’s 14 newly reported cases, 11 had paralysis onset in 2025.

Case Numbers and Environmental Findings

At the time of the assessment, four WPV1 cases had been reported so far in 2026 – three in Afghanistan and one in Pakistan. In 2025, Afghanistan recorded 21 cases and Pakistan 31, for a combined total of 52. More recent surveillance updates have shown additional detections, with Afghanistan’s 2026 total rising to 19 cases by mid-August, bringing the regional figure to 22.

Environmental surveillance has continued to detect the virus. A total of 74 WPV1-positive environmental samples were reported globally in 2026 up to the committee’s review, including 17 from Afghanistan and 57 from Pakistan. In 2025, 747 positive samples were recorded, including 94 from Afghanistan and 651 from Pakistan. Later regional bulletins indicated higher cumulative environmental detections for the year, underscoring persistent circulation even as overall numbers decline.

The committee noted that the overall number of cases and positive environmental samples is declining but warned that transmission has continued in both countries, including through the most recent low-transmission season.

Hotspots of Greatest Concern

Three areas were singled out as particularly worrying: southern Afghanistan, southern Khyber Pakhtunkhwa in Pakistan, and Karachi. Southern Afghanistan was described as the area of greatest concern, with intense transmission and evidence that the virus has circulated undetected for extended periods. Southern Khyber Pakhtunkhwa continues to face security and operational challenges that hinder vaccination efforts, while Karachi remains a significant reservoir for poliovirus.

Progress has been recorded in some areas, including eastern Afghanistan and the Peshawar and Quetta regions of Pakistan. However, those gains remain fragile because of immunity gaps, population movement, vaccine refusals, surveillance concerns and uneven vaccination coverage.

Cross-Border Challenges and Sample Transport

The WHO stressed that Afghanistan and Pakistan should continue to be treated as a single epidemiological bloc because of the continuing risk of cross-border transmission. Movement between the two countries, including the return of undocumented Afghans from Pakistan, continues to complicate eradication efforts.

The closure of the Afghanistan-Pakistan land border disrupted the transport of polio surveillance samples from Afghanistan to the regional reference laboratory in Islamabad between October 2025 and early January 2026. Sample shipments resumed in January, and all Afghan samples from 2025 have now been tested and finalised. Because the land border remains closed, samples are now being transported by air. The WHO is also working with other laboratories in the region to establish backup testing capacity.

Vaccination Campaign Gaps

Afghanistan and Pakistan have continued intensive vaccination campaigns, yet significant gaps persist. In Afghanistan, campaigns are being conducted through a site-to-site strategy. House-to-house campaigns have not been carried out since October 2024 because of security concerns. Limited participation of women health workers, particularly in southern Afghanistan, is another concern. Officials warned that site-to-site campaigns may fail to reach some children, especially younger ones, potentially allowing the virus to spread further.

In Pakistan, the committee welcomed strong political support for polio eradication and generally high reported vaccination coverage. However, the quality of campaigns varies at the district level, particularly in southern Khyber Pakhtunkhwa and Balochistan. About 250,000 children in southern Khyber Pakhtunkhwa remain unreached, largely because insecurity restricts access.

Vaccine-Derived Poliovirus Outbreaks

The committee also reviewed outbreaks of circulating vaccine-derived poliovirus, or cVDPV. As of 30 April 2026, 32 cVDPV cases had been reported globally across 12 countries. Of those, 28 were cVDPV2, two were cVDPV3 and two were cVDPV1. All 27 environmental detections reported during the period were cVDPV2.

Nigeria recorded the largest number of cVDPV2 cases this year, with 14 as of the end of April, accounting for half of the global total at that point. Transmission also continues in parts of the Lake Chad Basin and the Horn of Africa, including Somalia, Ethiopia and Yemen. Humanitarian crises, insecurity, population displacement and low routine immunisation coverage continue to create conditions in which vaccine-derived poliovirus can spread.

Call for Sustained Action

After reviewing the global epidemiological and vaccination situation, the committee recommended extending the temporary measures associated with the PHEIC for another three months. The continued international risk is driven by ongoing transmission in endemic countries, gaps in population immunity, cross-border movement and the potential for poliovirus to spread from endemic countries to other parts of the world.

Continued high-quality surveillance, vaccination campaigns and coordinated cross-border efforts will be essential to interrupt transmission. Progress in Afghanistan and Pakistan remains fragile. Reducing transmission will require both countries to reach children missed by vaccination campaigns and to maintain close coordination along their shared border.

The Director-General accepted the committee’s assessment and determined that the poliovirus situation continues to constitute a public health emergency of international concern with respect to WPV1 and cVDPV. The temporary recommendations under the International Health Regulations were extended accordingly.

Polio remains a highly contagious disease that mainly affects children under five. While global cases have fallen dramatically over decades of eradication efforts, the final stages are proving the most challenging. The virus continues to find refuge in communities where conflict, insecurity, displacement and access restrictions leave children unprotected. Until every last transmission chain is broken, the risk of international spread – and the need for emergency measures – will persist.