Monday, July 28, 2025
The Forty-second meeting of the Emergency Committee under the International Health Regulations (2005) (IHR) on the international spread of poliovirus was convened by the WHO Director-General on 18 June 2025, with committee members and advisers meeting via video conference. The Committee reviewed the data on wild poliovirus (WPV1) and circulating vaccine-derived polioviruses (cVDPV) in the context of the global target of interruption and certification of WPV1 eradication by 2027 and interruption and certification of cVDPV2 elimination by 2029. Technical updates were received about the situation in the following countries: Afghanistan, Angola, Burkina Faso, Guinea, Nigeria, Pakistan, and Papua New Guinea. Since the last meeting, nine new WPV1 cases were reported, one from Afghanistan and eight from Pakistan, totaling 13 cases in 2025. In 2024, 99 WPV1 cases were reported during the whole year, including 25 from Afghanistan and 74 from Pakistan. A total of 275 WPV1 positive environmental samples have been reported in 2025 so far, with 30 from Afghanistan and 245 from Pakistan. In 2024, 741 WPV1 positive environmental samples were reported, including 113 from Afghanistan and 628 from Pakistan. The upward trend in WPV1 cases and environmental detections has persisted in both endemic countries throughout 2024. In Pakistan, this increase has been evident since mid-2023, initially in environmental samples and later in paralytic polio cases, primarily in Khyber Pakhtunkhwa (KP), Sindh, and Balochistan. In Afghanistan, the rise in WPV1 detections, both in environmental samples and cases during 2024 and 2025, has been concentrated primarily in the South Region. WPV1 transmission in Afghanistan’s East Region has significantly declined during the first half of 2025, indicating enhanced population immunity. The Committee noted with concern the geographic expansion of WPV1 to new provinces and districts in both endemic countries during 2024 and 2025. Notably, Gilgit-Baltistan province in Pakistan reported its first WPV1 case in over eight years, underscoring the continued risk posed by persistent transmission in core reservoir areas. Currently, the most intense WPV1 transmission is occurring in the southern cross-border epidemiological corridor, encompassing Quetta Block (Pakistan) and the South Region (Afghanistan). The Committee also noted the ongoing WPV1 transmission in the epidemiologically critical blocks of Karachi, South KP, and Central Pakistan. The review of molecular epidemiology shows an increase in genetic biodiversity in 2024, necessitating a split of two genetic clusters into eight genetic clusters. Three genetic clusters are active in 2025. The remaining chains of transmission continue to circulate in populations and geographic areas with persistently low immunization coverage, including the bordering districts of the southern and northern epidemiological corridors across the two endemic countries. The genetic data analysis also indicates that WPV1 persisted through the low transmission season (October 2024 to April 2025) within the core reservoirs of Southern Afghanistan, Karachi, Peshawar, and the Quetta Block - posing a risk to achieving Goal 1 of the GPEI strategy by end-2025. Afghanistan and Pakistan continue to implement an intensive and mostly synchronized campaign schedule, with a focus on achieving high vaccination coverage in core reservoirs and ensuring timely, effective response to WPV1 detections in other areas of each country. Afghanistan implemented two nationwide and two sub-national vaccination rounds while Pakistan implemented three nationwide and one sub-national vaccination round in 2025, so far. In Afghanistan, campaigns are being conducted using the site-to-site strategy, with focused efforts to strengthen operational and communication approaches to maximize coverage of target children under this modality. The Committee expressed concern that site-to-site campaigns often fail to reach all children, particularly younger children and girls, which could contribute to a resurgence of WPV1 and its further geographic spread within Afghanistan and beyond. The Committee noted with appreciation the strong leadership and high-level commitment to polio eradication in Pakistan at all levels, including the direct engagement of the Prime Minister, the Federal Minister for Health, and the Prime Minister’s Focal Person for Polio Eradication. The Committee also acknowledged the consistently high reported coverage and Lot Quality Assurance Sampling (LQAS) pass rates at the national and provincial levels. However, the Committee observed variability in campaign quality at the district and sub-district levels, attributed to operational challenges and prevailing insecurity, particularly in Khyber Pakhtunkhwa and Balochistan provinces. In addition to seasonal population movements within and between the two endemic countries, the continued return of undocumented migrants from Pakistan to Afghanistan further compounds the challenges faced by the programme. This ongoing displacement heightens the risk of cross-border poliovirus transmission, as well as transmission within both countries. The Committee noted that this risk is being addressed through vaccination at border crossing points and the revision of micro-plans in districts of origin and return. The programme continues to coordinate closely with IOM and UNHCR. The Committee also acknowledged the ongoing coordination between the Afghanistan and Pakistan programmes at both national and sub-national levels and encouraged the continuation of these collaborative efforts. In summary, available data indicate that global WPV1 transmission remains geographically confined to the two endemic countries. However, during 2024 and 2025, there has been geographic spread alongside continued transmission within core reservoir areas in both the endemic countries. In 2025, a total of 67 cVDPV cases have been reported to date, 65 of which are cVDPV2 and two are cVDPV3. No cVDPV1 cases have been reported in 2025. Additionally, 69 environmental samples have tested positive for cVDPV, all of which are type 2. In 2024, a total of 319 cVDPV cases were reported, including 304 cVDPV2, 11 cVDPV1, and 4 cVDPV3 cases. During the same year, 276 environmental samples tested positive for cVDPV, 273 cVDPV2 and three cVDPV3. Since the last meeting of the Emergency Committee, a cVDPV2 outbreak has been reported from Papua New Guinea in the WHO Western Pacific Region.
Reference: Statement of the Forty-second meeting of the Polio IHR Emergency CommitteeLabels: WHO
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