04/10/2025 | Press release | Distributed by Public on 04/10/2025 06:21
The 41st 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 06 March 2024 with committee members and advisers meeting via video conference with affected countries, supported by the WHO Secretariat. The Emergency 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, Algeria, Chad, Democratic Republic of the Congo (DR Congo), Djibouti, Ethiopia, Germany, Pakistan, Poland and the United Kingdom of Great Britain and Northern Ireland.
Since the last Emergency Committee meeting, 36 new WPV1 cases were reported, three from Afghanistan and 33 from Pakistan bringing the total to 99 WPV1 cases in 2024 and three in 2025. This represents more than four-fold increase in Afghanistan and more than 12-fold increase in Pakistan in the number of WPV1 cases from 2023 to 2024. A total of 741 WPV1 positive environmental samples were reported in 2024, 113 from Afghanistan and 628 from Pakistan. In 2025, 80 WPV1-positive environmental samples have been reported, 9 from Afghanistan and 71 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 has been predominantly in the South Region. The Committee noted the geographic spread of WPV1 to new provinces and districts in both endemic countries in 2024 and observed that WPV1 transmission has re-established in historical reservoirs, including Kandahar (Afghanistan), Peshawar, Karachi, and Quetta Block (Pakistan). 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 South KP and Central Pakistan blocks of Pakistan.
Review of the molecular epidemiology indicates that there has been progressive elimination of the genetic cluster 'YB3C' in 2022 and 2023, with its last detection in November 2023 in Bannu district of Khyber Pakhtunkhwa province of Pakistan. However, there has been persistent transmission of YB3A genetic cluster since May 2022, resulting in its split into two: YB3A4A and YB3A4B. During the first half of 2024, the cluster YB3A4A was mainly circulating in the northern and southern cross-border corridors. During the second half of 2024 there was distinct expansion of both these genetic clusters seen in Pakistan, more pronounced for YB3A4A. In Afghanistan, the predominantly circulating genetic cluster in YB3A4A.
Both Afghanistan and Pakistan continue to implement an intensive and mostly synchronized campaign schedule focusing on improved vaccination coverage in the endemic zones and effective and timely response to WPV1 detections elsewhere in each country. Afghanistan implemented five sub-national vaccination rounds during the second half of 2024, targeting infected and high-risk provinces, while Pakistan implemented two nationwide and a large scale sub-national vaccination round from September through December 2024. After encouraging progress towards implementing house-to-house campaigns in all of Afghanistan during the first half of 2024, Afghanistan programme has not been able to implement house-to-house campaigns during most of the second half of 2024. All vaccination campaigns in Afghanistan since October 2024 have been implemented using alternate modalities (mostly site-to-site). The committee was concerned that site-to-site campaigns are usually not able to reach all the children, especially those of younger age and girls, which may lead to a further upsurge of WPV1 with geographical spread in Afghanistan and beyond. Afghanistan programme is taking measures to maximize the reach of site-to-site campaigns through adequate operational and social mobilization measures. The Committee noted overall high reported coverage of the vaccination campaigns in Pakistan; however, variations were observed about the quality at the sub-provincial and sub-district levels, relating to operational implementation challenges and increasing insecurity, particularly in the Khyber Pakhtunkhwa and Balochistan provinces. Nearly 200,000 and 50,000 missed children were reported from the South KP and Quetta Block (Balochistan) in Pakistan at the end of October and December 2024 campaigns.
In addition to seasonal movement patterns within and between the two endemic countries, the continued return of undocumented migrants from Pakistan to Afghanistan compounds the challenges faced. The scale of the displacement increases the risk of cross-border poliovirus spread as well as spread within both the countries. This risk is being managed and mitigated in both countries through vaccination at border crossing points and the updating of micro-plans in the districts of origin and return. The programme continues to closely coordinate with IOM and UNHCR. The Committee noted ongoing coordination between the programmes of Afghanistan and Pakistan at the national and sub-national levels.
In summary, the available data indicate that globally transmission of WPV1 is geographically limited to the two WPV1 endemic countries; however, there has been geographical spread and intensifying transmission within the two endemic countries in 2024.
In 2024, there have been 280 cVDPV cases, of which 265 are cVDPV2, 11 cVDPV1 and four are cVDPV3. Additionally, 257 environmental samples were positive for cVDPV, 254 positive cVDPV2 and three cVDPV3. Of the 265 cVDPV2 cases in 2024, 94 (36%) have occurred in Nigeria. Of the 11 cVDPV1 cases in 2024, 10 were reported from DR Congo and one from Mozambique. All the four cVDPV3 cases in 2024 were reported from Guinea.
A total of 528 cases have been confirmed with cVDPV in all of 2023, of which 395 are cVDPV2 and 134 are cVDPV1 (one case co-infected with cVDPV1 and cVDPV2). Of the 528 cVDPV cases reported in 2023, 226 (43%) have occurred in the DR Congo.
Since the last meeting of the Emergency Committee, new cVDPV2 detections were reported from Finland, Germany, Poland and the United Kingdom of Great Britain and Northern Ireland and new cVDPV3 detections from Guinea.
In 2024, the total number of circulating cVDPV2 emergence groups detected to date is 26, compared to 27 in 2023, 22 in 2022, 29 in 2021, 36 in 2020, and 44 in 2019. Of the 26 emergence groups circulating in 2024, eleven are newly detected in 2024, 10 derived from the novel OPV2 vaccine. There have now been 25 nOPV2 derived cVDPV2 emergences since 2021. The committee noted that the nOPV2 vaccine continues to demonstrate significantly higher genetic stability and substantially lower likelihood of reversion to neurovirulence relative to Sabin OPV2.
A total of 11 cVDPV1 cases have been reported in 2024, 10 in the Democratic Republic of the Congo and one in Mozambique. This compares to 134 cVDPV1 cases in all of 2023 (106 in Democratic Republic of the Congo, 24 in Madagascar, four in Mozambique), representing a 92% reduction in the global cVDPV1 paralytic burden from 2023. However, one new emergence has been reported from the Tshopo province in the Democratic Republic of the Congo (RDC-TSH-3). This is the first cVDPV1 emergence reported since September 2022. The committed noted encouraging progress in Madagascar towards interrupting local cVDPV1 transmission, with no detections for more than 16 months.
In 2024, two countries reported cVDPV3 outbreaks: French Guiana (French territory in South America) and Guinea. Both cVDPV3 outbreaks in 2024 were due to new emergences, leading to three positive environmental samples in French Guiana (May to August 2024) and four cVDPV3 cases in Guinea (July to November 2024). The committee noted that these cVDPV3 outbreaks were reported after a significant interval, with the last cVDPV3 outbreak reported in March 2022.
In 2024, DR Congo and Mozambique reported co-circulation of cVDPV1 and cVDPV2, while Guinea detected co-circulation of cVDPV2 and cVDPV3.
The Committee noted that the risk of cVDPV outbreaks is largely driven by a combination of inaccessibility, insecurity, high concentrations of zero-dose and under-immunized children, and ongoing population displacement.
The Committee unanimously agreed that the risk of international spread of poliovirus continues to constitute a Public Health Emergency of International Concern (PHEIC) and recommended extending the Temporary Recommendations for a further three months. In reaching this conclusion, the Committee considered the following factors:
Ongoing risk of WPV1 international spread:
Based on the following factors, there remains the risk of international spread of WPV1:
Ongoing risk of cVDPV international spread:
Based on the following factors, the risk of international spread of cVDPV appears to remain high:
Contributing factors include:
Risk categories
The Committee provided the Director-General with the following advice aimed at reducing the risk of international spread of WPV1 and cVDPVs, based on the risk stratification as follows:
Criteria to assess States as no longer infected by WPV1 or cVDPV:
Once a country meets these criteria as no longer infected, the country will remain on a 'watch list' for a further 12 months for a period of heightened monitoring. After this period, the country will no longer be subject to Temporary Recommendations.
TEMPORARY RECOMMENDATIONS
States infected with WPV1, cVDPV1 or cVDPV3 with potential risk of international spread
(as of data available at WHO HQ on 20 February 2025)
WPV1
Afghanistan most recent detection 27 Jan 2025
Pakistan most recent detection 30 Jan 2025
cVDPV1
Mozambique most recent detection 17 May 2024
DR Congo most recent detection 19 Sep 2024
cVDPV3
French Guiana (France) most recent detection 06 Aug 2024
Guinea most recent detection 21 Nov 2024
These countries should:
States infected with cVDPV2, with or without evidence of local transmission:
(as of data available at WHO HQ on 20 February 2025)
and Northern Ireland most recent detection 11 Dec 2024
States that have had an importation of cVDPV2 but without evidence of local transmission should:
States with local transmission of cVDPV2, with risk of international spread, in addition to the above measures, should:
For both sub-categories:
States no longer polio infected, but previously infected by WPV1 or cVDPV within the last 24 months (as of data available at WHO HQ on 20 February 2024)
WPV1
country last virus date
cVDPV
country last virus date
These countries should:
Additional considerations
The Committee noted that the Global Polio Eradication Initiative needs to reconsider its priorities and reprogram its operations in response to the current fiscal constraints. The current financial shortfall poses a significant risk to eradication efforts. The Committee acknowledges and appreciates the Kingdom of Saudi Arabia's recent confirmation of its $500 million commitment to global polio eradication. The committee urged donor countries and organizations to enhance their financial support, emphasizing that failure is not an option. The Committee also called on national governments to prioritize polio eradication in their domestic funding allocations to ensure sustained progress toward eradication.
The Committee expressed deep concern over the escalating and expanding WPV1 transmission in Afghanistan and Pakistan. The persistence of WPV1 transmission despite ongoing vaccination campaigns highlights gaps in immunization quality. The Committee also noted that the current levels of WPV1 transmission during the low season could further intensify during the high transmission season if uniform, high-quality campaigns, particularly in core reservoir areas, are not ensured.
The Committee remains concerned about the continued inability to conduct house-to-house vaccination campaigns in Afghanistan. This challenge places infants and young children, particularly girls, at a heightened risk of missing polio vaccination. The Committee appreciates the efforts to improve women's participation in site-to-site polio vaccination as well as for border vaccination and encourages to expand these efforts to high-risk South Region of Afghanistan.
The Committee acknowledged the strong political commitment to polio eradication in Afghanistan and Pakistan. The Committee emphasized that this commitment must translate into concrete operational actions to strengthen community engagement and implement high-quality vaccination campaigns. These efforts are essential to interrupt the ongoing intense WPV1 transmission and mitigate the risk of national and international spread. In Afghanistan. The Committee specifically recommended the resumption of house-to-house vaccination campaigns and the recruitment of additional female vaccinators to enhance community acceptance and improve coverage.
The Committee is encouraged by the improving cVDPV1 situation in the African Region, particularly in Madagascar, which has not reported any cases for over 16 months. The Committee emphasized the need to sustain high-quality vaccination efforts, particularly in the DR Congo and Mozambique, the only two countries that have reported cVDPV1 cases in 2024.
The Committee noted the ongoing transmission of cVDPV2 in the African Region, particularly in northern Nigeria. While there has been an overall decline in cVDPV2 cases in 2024, the Committee expressed concern over the increase in cases reported by Angola, Ethiopia, Niger, Nigeria, South Sudan, and Yemen compared to 2023. The Committee also noted the concerning cVDPV2 epidemiological situation in Chad and Algeria and recommended the implementation of high-quality vaccination campaigns to boost population immunity. The Committee noted the challenges in implementing high-quality immunization responses in critical areas of the African Region and northern Yemen. Additionally, the Committee expressed concerns over surveillance gaps in northern Yemen, which may further hinder early detection and response efforts.
The Committee noted the detection of cVDPV3 in Guinea and French Guiana in 2024, after more than two years with no reported detections globally and emphasized the need for a high-quality surveillance and immunization response to contain these outbreaks.
The Committee noted that several cVDPV-affected countries continue to face conflict and insecurity, which disrupts both routine immunization and polio vaccination campaigns. The Committee also noted that ongoing health emergencies and disease outbreaks in several countries further complicate the timely and effective implementation of polio vaccination campaigns. Given the diverse challenges across countries and sub-national areas, the Committee emphasized the need for context-specific, tailored interventions to ensure high-quality campaigns and ultimately stop cVDPV outbreaks. The Committee also underscored the importance of synchronized sub-regional approaches and strong cross-border coordination to address challenges related to permeable borders and shared operational constraints across affected countries.
The Committee noted some good practices in several countries, particularly in cross-border collaboration and surveillance. The Committee encourages countries to document and share these best practices and suggests that GPEI facilitates this process.
The Committee noted the ongoing cross-border spread of cVDPV2 in the African and Eastern Mediterranean Regions, as well as the recent detection of cVDPV2 in five countries of the European Region. This reinforces that polio remains a global risk until it is fully eradicated. The Committee acknowledged the ongoing response efforts of Finland, Germany, Poland, Spain, and the United Kingdom of Great Britain and Northern Ireland in strengthening surveillance and addressing sub-national immunity gaps. The Committee also appreciated the inter-country coordination in the European Region, facilitated by the WHO European Regional Office, in response to the cVDPV2 detections in the region. The Committee recommended continued surveillance strengthening across the European Region, along with regular risk assessments to ensure timely identification and mitigation of emerging polio risks.
The Committee highlighted the importance of maintaining sensitive surveillance in polio-infected and high-risk countries and recommended that GPEI provide all possible support under the Global Polio Surveillance Action Plan. The Committee also underscored the importance of high-income countries maintaining high-quality surveillance for polioviruses, given the ongoing risk of importation, as recently demonstrated by cVDPV detections in the European Region. Robust surveillance remains essential for early detection and timely response to importations and newly emerging outbreaks.
The Committee noted that novel OPV2 continues to demonstrate greater genetic stability compared to Sabin OPV2. However, the risk of new cVDPV2 emergences increases when the interval between outbreak response campaigns exceeds four weeks or when vaccination quality is suboptimal, underscoring the need for timely and high-quality immunization efforts.
The Committee noted that the amendments to the International Health Regulations (2005) (IHR) through resolution WHA77.17 (2024), were notified to States Parties on 19 September 2024 and that they would come into effect on 19 September 2025 for 192 States Parties. Regarding any potential effects of these amendments on the Committee, the Secretariat informed the Committee that it would be premature to assess any such effects at this time but would brief the Committee ahead of their entry into force in September 2025, should the Committee continue to be convened under the IHR at this time.
Based on the current situation regarding WPV1 and cVDPVs, and the reports provided by affected countries, the Director-General accepted the Committee's assessment, and on 09 April 2025 determined that the poliovirus situation continues to constitute a Public Health Emergency of International Concern (PHEIC) with respect to WPV1 and cVDPV. The Director-General endorsed the Committee's recommendations for countries meeting the definition for 'States infected with WPV1, cVDPV1 or cVDPV3 with potential risk for international spread', 'States infected with cVDPV2 with potential risk for international spread' and for 'States previously infected by WPV1 or cVDPV within the last 24 months' and extended the Temporary Recommendations under the IHR to reduce the risk of the international spread of poliovirus, effective, 09 April 2025.