The thirty-ninth assembly of the Emergency Committee beneath the Worldwide Well being Rules (2005) (IHR) on the worldwide unfold of poliovirus was convened by the WHO Director-Common on 08 July 2024 with committee members and advisers assembly by way of video convention with affected international locations, supported by the WHO Secretariat. The Emergency Committee reviewed the information on wild poliovirus (WPV1) and circulating vaccine derived polioviruses (cVDPV) within the context of the worldwide goal of interruption and certification of WPV1 eradication by 2026 and interruption and certification of cVDPV2 elimination by 2028. Technical updates had been obtained in regards to the scenario within the following international locations: Afghanistan, Ethiopia, Equatorial Guinea, Kenya, Mali, Niger, Pakistan, Senegal, and Somalia.
Wild poliovirus
Because the final Emergency Committee assembly, twelve new WPV1 instances had been reported, 5 from Afghanistan and 7 from Pakistan bringing the entire to 14 in 2024. The variety of WPV1 optimistic environmental samples in Pakistan in 2024 is 186 in comparison with 126 throughout all of 2023. The variety of WPV1 optimistic environmental samples in Afghanistan in 2024 is 44 in comparison with 62 in all of 2023.
There was an upward pattern of WPV1 detection in Pakistan since mid-2023, primarily within the environmental samples from Khyber Pakhtunkhwa, Sindh and Balochistan provinces. In Afghanistan, there may be elevated WPV1 detection within the environmental samples within the South Area since late 2023, along with reporting of two WPV1 instances. The committee famous the conclusion of lately held assembly of the Technical Advisory Group (TAG) on polio eradication in Afghanistan and Pakistan that regardless of general progress, endemic transmission has been re-established within the historic reservoirs of Kandahar (Afghanistan) and Peshawar (Pakistan) and there may be danger of its re-establishment in Karachi and Quetta Block of Pakistan. Overview of the molecular epidemiology signifies that there was progressive elimination of the genetic cluster ‘YB3C’ in 2022 and 2023, with its final detection in November 2023 in Bannu district of Khyber Pakhtunkhwa (KP) province of Pakistan. Nevertheless, there was persistent transmission of YB3A genetic cluster since Could 2022, ensuing into its cut up into two: YB3A4A and YB3A4B. The YB3A4A is a shared cluster within the northern and southern cross-border corridors throughout Afghanistan and Pakistan, whereas the YB3A4B is principally energetic in Pakistan.
Each Afghanistan and Pakistan proceed to implement an intensive and synchronized marketing campaign schedule specializing in improved vaccination protection within the endemic zones and efficient and well timed response to WPV1 detections elsewhere in every nation. Each international locations carried out two nationwide and two sub-national vaccination campaigns throughout the first half of 2024. Throughout the June 2024 nation-wide vaccination marketing campaign, Afghanistan for the primary time after greater than 5 years, utilized house-to-house vaccination technique within the South Area with exception of the Kandahar province, which is a really encouraging growth. The marketing campaign high quality within the endemic East Area of Afghanistan has reportedly been excessive in 2024. Nationally, 95% of the goal youngsters (aged < 5 years) in Afghanistan had been reached by house-to-house vaccination technique throughout the June 2024 marketing campaign and 5% by way of different modalities. The marketing campaign high quality within the areas with house-to-house to vaccination is considerably higher than the areas utilizing different modalities. Throughout April 2024 nationwide marketing campaign in Afghanistan, 17% of the vaccination volunteers had been ladies, representing about 3% enchancment since December 2023. In Pakistan, the marketing campaign high quality within the endemic zone of South KP and historic WPV1 reservoirs continues to face challenges referring to operational implementation and growing insecurity notably within the KP and Balochistan provinces. Regardless of latest progress within the endemic South KP in Pakistan, there are regarding numbers of missed youngsters throughout the latest campaigns (starting from 5000 to 700,000) as a consequence of insecurity, boycotts and programme high quality points. Key AFP surveillance efficiency indicators aren’t assembly the targets in a number of the districts of South KP of Pakistan. Along with seasonal motion patterns inside and between the 2 endemic international locations, the continued return of undocumented migrants from Pakistan to Afghanistan compounds the challenges confronted. The size of the displacement will increase the danger of cross-border poliovirus unfold in addition to unfold inside each the international locations. This danger is being managed and mitigated in each international locations by way of vaccination at border crossing factors and the updating of micro-plans within the districts of origin and return. The programme continues to carefully coordinate with IOM and UNHCR.
There was no transmission of WPV1 within the African Area in 2024. Following an impartial Outbreak Response Evaluation (OBRA) in Malawi and Mozambique, the WPV1 outbreak within the African Area has been declared closed as of Could 2024.
In abstract, the obtainable knowledge point out that globally transmission of WPV1 is geographically restricted to the 2 WPV1 endemic international locations; nonetheless, there was geographical unfold throughout the two international locations in 2023 and 2024.
Circulating vaccine derived poliovirus (cVDPV)
In 2024, there have been 72 instances confirmed with cVDPV, of which 68 are cVDPV2 and 4 are cVDPV1. Of the 72 instances in 2024, 30 (42%) have occurred in Nigeria. Algeria, Cote d’Ivoire, Egypt, Equatorial Guinea, Gambia, Liberia, Mozambique, Senegal, Sierra Leone, Sudan, Uganda, and Zimbabwe have detected cVDPV within the atmosphere however haven’t detected any instances.
A complete of 527 instances have been confirmed with cVDPV in all of 2023, of which 393 are cVDPV2 and 134 are cVDPV1. Of the 527 cVDPV instances reported in 2023, 224 (43%) have occurred within the DR Congo.
There are two newly contaminated international locations reporting cVDPV2 because the final assembly: Ethiopia and Equatorial Guinea. Each Ethiopia and Equatorial Guinea skilled importations, from South Sudan and Chad respectively. In 2024, the variety of circulating cVDPV2 emergence teams detected thus far is 13, in comparison with 27 in 2023, 22 in 2022, 29 in 2021, 36 in 2020, and 44 in 2019. Of the 13 emergence teams circulating in 2024, two are a newly detected this 12 months, each derived from the novel OPV2 vaccine. There have now been 17 nOPV2 derived cVDPV2 emergences since 2021.
All of the 4 cVDPV1 instances in 2024 have been reported from DR Congo. In 2023, a complete of 134 cVDPV1 instances had been reported together with 106 from DR Congo, 24 from Madagascar, and 4 from Mozambique. Final cVDPV1 detection from Madagascar was in September 2023 and from Mozambique in November 2023.
The committee famous that within the African Area, which now, solely makes use of novel OPV2 for outbreak response, there was a complete of 16 new cVDPV2 emergences detected which have emerged from novel OPV2 use, whereas there was one such emergence recognized in Egypt within the Jap Mediterranean Area. The committee famous that a lot of the danger for cVDPV outbreaks might be linked to a mix of inaccessibility, insecurity, a excessive focus of zero dose and under-immunized youngsters and inhabitants displacement. These elements are most evident in northern Yemen, northern Nigeria, south-central Somalia and japanese DR Congo.
Conclusion
The Committee unanimously agreed that the danger of worldwide unfold of poliovirus nonetheless stays a Public Well being Emergency of Worldwide Concern (PHEIC) and beneficial the extension of Non permanent Suggestions for an additional three months. The Committee thought of the next elements in reaching this conclusion:
Ongoing danger of WPV1 worldwide unfold:
Primarily based on the next elements, the danger of worldwide unfold of WPV1 stays:
- Unfold of WPV1 transmission again into previously endemic areas and core reservoirs of Afghanistan (Kandahar) and Pakistan (Karachi, Peshawar, Quetta Block), that represents a big danger to the positive aspects made over the past two years.
- The WPV1 transmission has basically re-established in Kandahar (Afghanistan) and Peshawar (Pakistan).
- This epidemiological context is especially regarding on the outset of excessive transmission season in each endemic international locations.
- Regardless of general resumption of house-to-house vaccination campaigns in Southern Afghanistan, Kandahar province continues to implement site-to-site or mosque-to-mosque campaigns, which has been proven to be much less efficient than the house-to-house technique;
- Sure geographies and inhabitants pockets within the epidemiologically important areas of Pakistan proceed to have inconsistent marketing campaign high quality and substantial variety of unimmunized and under-immunized youngsters
- Excessive-risk cell populations in Pakistan characterize a selected danger of worldwide unfold to Afghanistan particularly, compounded by ongoing important motion the returnees from Pakistan into a lot of provinces of Afghanistan;
- Any setback in Afghanistan poses a danger to the programme in Pakistan as a consequence of excessive inhabitants motion.
Ongoing danger of cVDPV worldwide unfold:
Primarily based on the next elements, the danger of worldwide unfold of cVDPV2 seems to stay excessive though numbers of cVDPV1 instances have gone down:
- Ongoing cross border unfold together with into newly re-infected international locations comparable to Ethiopia and Equatorial Guinea
- Continued cVDPV2 transmission within the important areas of Nigeria, with greater than 40% of the worldwide cVDPV2 instances in 2024 and it is potential to amplify the transmission
- The cVDPV2 transmission within the Horn of Africa appears to be intensifying throughout the first half of 2024. The Horn of Africa international locations proceed to face humanitarian and well being emergencies making it very difficult to implement high-quality vaccination campaigns in a well timed method.
- There’s a giant pool of unimmunized prone youngsters within the Northern Governorates of Yemen
- Regardless of the reducing variety of cVDPV instances, the transmission continues to be detected in DR Congo, as latest as April 2024 for cVDPV1 and March 2024 for cVDPV2
- The ever-widening hole in inhabitants intestinal mucosal immunity in younger youngsters because the withdrawal of OPV2 in 2016 and consequently excessive focus of zero dose youngsters in sure areas;
- Insecurity in lots of areas which can be the supply of cVDPV transmission.
Contributing elements embody:
- Weak routine immunization: Many international locations have weak immunization programs that may be additional impacted by humanitarian emergencies together with battle and protracted advanced emergencies. This poses a rising danger, leaving populations in these fragile states weak to polio outbreaks.
- Lack of entry: Inaccessibility continues to be a serious danger, notably in northern Yemen and Somalia which have sizable populations which have been unreached with polio vaccine for prolonged durations of greater than a 12 months.
Danger classes
The Committee supplied the Director-Common with the next recommendation geared toward lowering the danger of worldwide unfold of WPV1 and cVDPVs, based mostly on the danger stratification as follows:
- States contaminated with WPV1, cVDPV1 or cVDPV3.
- States contaminated with cVDPV2, with or with out proof of native transmission.
- States beforehand contaminated by WPV1 or cVDPV throughout the final 24 months.
Standards to evaluate States as not contaminated by WPV1 or cVDPV:
- Poliovirus Case: 12 months after the onset date of the latest case PLUS one month to account for case detection, investigation, laboratory testing and reporting interval OR when all reported AFP instances with onset inside 12 months of final case have been examined for polio and excluded for WPV1 or cVDPV, and environmental or different samples collected inside 12 months of the final case have additionally examined destructive, whichever is the longer.
- Environmental or different isolation of WPV1 or cVDPV (no poliovirus case): 12 months after assortment of the latest optimistic environmental or different pattern (comparable to from a wholesome little one) PLUS one month to account for the laboratory testing and reporting interval.
- These standards could also be various for the endemic international locations, the place extra rigorous evaluation is required in reference to surveillance gaps.
As soon as a rustic meets these standards as not contaminated, the nation shall be stay on a ‘watch record’ for an additional 12 months for a interval of heightened monitoring. After this era, the nation will not be topic to Non permanent Suggestions.
TEMPORARY RECOMMENDATIONS
States contaminated with WPV1, cVDPV1 or cVDPV3 with potential danger of worldwide unfold
WPV1
Afghanistanmost latest detection 22 Could 2024
Pakistanmost latest detection 4 June 2024
cVDPV1
Madagascarmost latest detection 16 September 2023
Mozambiquemost latest detection 6 November 2023
Democratic Republic of the Congomost latest detection 27 April 2024
These international locations ought to:
- Formally declare, if not already finished, on the stage of head of state or authorities, that the interruption of poliovirus transmission is a nationwide public well being emergency and implement all required measures to help polio eradication; the place such declaration has already been made, this emergency standing ought to be maintained so long as the response is required.
- Make sure that all residents and longterm guests (> 4 weeks) of all ages, obtain a dose of bivalent oral poliovirus vaccine (bOPV) or inactivated poliovirus vaccine (IPV) between 4 weeks and 12 months previous to worldwide journey.
- Make sure that these endeavor pressing journey (inside 4 weeks), who haven’t obtained a dose of bOPV or IPV within the earlier 4 weeks to 12 months, obtain a dose of polio vaccine at the very least by the point of departure as this can nonetheless present profit, notably for frequent vacationers.
- Make sure that such vacationers are supplied with an Worldwide Certificates of Vaccination or Prophylaxis within the type laid out in Annex 6 of the IHR to file their polio vaccination and function proof of vaccination.
- Prohibit on the level of departure the worldwide journey of any resident missing documentation of acceptable polio vaccination. These suggestions apply to worldwide vacationers from all factors of departure, regardless of the technique of conveyance (street, air and / or sea).
- Additional intensify crossborder efforts by considerably enhancing coordination on the nationwide, regional and native ranges to considerably improve vaccination protection of vacationers crossing the border and of excessive danger crossborder populations. Improved coordination of crossborder efforts ought to embody nearer supervision and monitoring of the standard of vaccination at border transit factors, in addition to monitoring of the proportion of vacationers which can be recognized as unvaccinated after they’ve crossed the border.
- Additional intensify efforts to extend routine immunization protection, together with sharing protection knowledge, as excessive routine immunization protection is a necessary component of the polio eradication technique, notably because the world strikes nearer to eradication. International locations which haven’t but launched IPV2 into their schedules ought to urgently implement this. As soon as obtainable, international locations also needs to take into account introducing the hexavalent vaccine now authorised by Gavi.
- Preserve these measures till the next standards have been met: (i) at the very least six months have handed with out new infections and (ii) there may be documentation of full software of top quality eradication actions in all contaminated and excessive danger areas; within the absence of such documentation these measures ought to be maintained till the state meets the above evaluation standards for being not contaminated.
- Present to the Director-Common a daily report on the implementation of the Non permanent Suggestions on worldwide journey.
States contaminated with cVDPV2, with or with out proof of native transmission:
1. Algeriamost latest detection 27 February 2024
2. Angolamost latest detection 30 March 2024
3. Beninmost latest detection 5 December 2023
4. Botswanamost latest detection 25 July 2023
5. Burkina Fasomost latest detection 4 June 2023
6. Burundimost latest detection 15 June 2023
7. Cameroonmost latest detection 28 September 2023
8. Central African Republicmost latest detection 7 October 2023
9. Chadmost latest detection 25 April 2024
10. Republic of the Congomost latest detection 7 December 2023
11. Côte d’Ivoiremost latest detection 23 April 2024
12. Democratic Republic of the Congomost latest detection 3 April 2024
13. Egyptmost latest detection 31 January 2024
14. Guineamost latest detection 26 March 2024
15. Ethiopiamost latest detection 06 April 2024
16. Gambiamost latest detection 15 February 2024
17. Guineamost latest detection 07 April 2024
18. Indonesiamost latest detection 7 December 2023
19. Kenyamost latest detection 21 February 2024
20. Liberiamost latest detection 16 April 2024
21. Malimost latest detection 2 January 2024
22. Mauritaniamost latest detection 13 December 2023
23. Mozambiquemost latest detection 5 March 2024
24. Nigermost latest detection 6 April 2024
25. Nigeriamost latest detection 25 April 2024
26. Senegalmost latest detection 16 April 2024
27. Sierra Leonemost latest detection 16 April 2024
28. Somaliamost latest detection 12 March 2024
29. South Sudanmost latest detection 7 Could 2024
30. Sudanmost latest detection 11 January 2024
31.Ugandamost latest detection 7 Could 2024
32. United Republic of Tanzaniamost latest detection 20 November 2023
33. Yemenmost latest detection 6 April 2024
34. Zambiamost latest detection 6 June 2023
35. Zimbabwemost latest detection 30 Could 2024
Word: After the assembly of the Emergency Committee, WHO was notified on 16 July 2024, of the detection of circulating vaccine-derived poliovirus kind 2 (cVDPV2) in 6 environmental samples from Deir Al Balah (3) and Khan Yunis (3) in Gaza Strip of the Occupied Palestinian Territory (oPt). All of the optimistic environmental samples had been collected on 23 June 2024. Efforts are already underway in any respect ranges to mount an outbreak response.
States which have had an importation of cVDPV2 however with out proof of native transmission ought to:
- Formally declare, if not already finished, on the stage of head of state or authorities, that the prevention or interruption of poliovirus transmission is a nationwide public well being emergency.
- Undertake pressing and intensive investigations to find out if there was native transmission of the imported cVDPV2.
- Noting the existence of a separate mechanism for responding to kind 2 poliovirus infections, take into account requesting vaccines from the worldwide novel OPV2 stockpile.
- Additional intensify efforts to extend routine immunization protection, together with sharing protection knowledge, as excessive routine immunization protection is a necessary component of the polio eradication technique, notably because the world strikes nearer to eradication. International locations which haven’t but launched IPV2 into their schedules ought to urgently implement this. As soon as obtainable, international locations also needs to take into account introducing the hexavalent vaccine now authorised by Gavi.
- Intensify nationwide and worldwide surveillance regional cooperation and crossborder coordination to reinforce surveillance for immediate detection of poliovirus.
States with native transmission of cVDPV2, with danger of worldwide unfold ought to along with the above measures ought to:
- Encourage residents and longterm guests to obtain a dose of IPV 4 weeks to 12 months previous to worldwide journey.
- Make sure that vacationers who obtain such vaccination have entry to an acceptable doc to file their polio vaccination standing.
- Intensify regional cooperation and crossborder coordination to reinforce surveillance for immediate detection of poliovirus, and vaccinate refugees, vacationers and crossborder populations.
For each sub-categories:
- Preserve these measures till the next standards have been met: (i) at the very least six months have handed with out the detection of circulation of VDPV2 within the nation from any supply, and (ii) there may be documentation of full software of top quality eradication actions in all contaminated and excessive danger areas; within the absence of such documentation these measures ought to be maintained till the state meets the standards of a ‘state not contaminated’.
- On the finish of 12 months with out proof of transmission, present a report back to the Director-Common on measures taken to implement the Non permanent Suggestions.
States not polio contaminated, however beforehand contaminated by WPV1 or cVDPV throughout the final 24 months
WPV1
nationfinal virusdate
1. MozambiqueWILD110 August 2022
cVDPV
nationfinal virusdate
1. CongocVDPV115 October2022
2. MalawicVDPV11 December 2022
3. CanadacVDPV230 August 2022
4. GhanacVDPV24 October 2022
5. IsraelcVDPV213 February 2023
6. MalawicVDPV22 January 2023
7. TogocVDPV230 September 2022
8. United States of AmericacVDPV220 October 2022
These international locations ought to:
- Urgently strengthen routine immunization to spice up inhabitants immunity.
- Improve surveillance high quality, together with contemplating introducing or increasing supplementary strategies comparable to environmental surveillance, to cut back the danger of undetected WPV1 and cVDPV transmission, notably amongst high-risk cell and weak populations.
- Intensify efforts to make sure vaccination of cell and crossborder populations, Internally Displaced Individuals, refugees and different weak teams.
- Improve regional cooperation and cross border coordination to make sure immediate detection of WPV1 and cVDPV, and vaccination of high-risk inhabitants teams.
- Preserve these measures with documentation of full software of high-quality surveillance and vaccination actions.
Further issues
The committee notes the geographic unfold of WPV1 in Pakistan and Afghanistan on the outset of excessive transmission season. Furthermore, consequent to persistent transmission in Afghanistan and Pakistan, the YB3A genetic cluster of WPV1 has cut up into two, YB3A4A and YB3A4B. The YB3A4A is a shared cluster within the northern and southern cross-border corridors throughout Afghanistan and Pakistan, whereas the YB3A4B is principally energetic in Pakistan.
The committee appreciates the latest steps taken (June 2024) by the Afghanistan Polio Programme in the direction of resumption of house-to-house campaigns in Southern Afghanistan, and notes with concern that Kandahar Province within the area continues to have a big pool of prone youngsters as a consequence of lack of ability to implement house-to-house campaigns, but. The committees notes that the general ladies’s inclusion in vaccination campaigns stays round 20% in Afghanistan, resulting in insufficient entry to all youngsters in some areas. The committee is inspired by the appointment of the Prime Minister’s Focal Individual for Polio Eradication in Pakistan. The Committee encourages Afghanistan and Pakistan polio programmes to keep up coordination, aiming to quickly enhance the entry and high quality of vaccination campaigns to have the ability to attain the Aim-1 of the GPEI technique.
The committee is inspired by the closure of WPV1 outbreak within the African Area and appreciates the efforts of Nationwide Governments and the GPEI on this regard. It is very important keep excessive inhabitants immunity by way of routine immunization to avert the danger of future WPV1 outbreaks within the African Area.
The committee famous the continued transmission of cVDPV within the African Area and that lots of the cVDPV contaminated international locations stay battle affected, disrupting routine immunization in addition to polio vaccination campaigns. The committee additionally famous that different well being emergencies and illness outbreaks (cholera, measles, dengue, malaria, and so on.) in a number of international locations of the African Area are making it very difficult to implement well timed and high-quality polio vaccination campaigns. The committee famous the deteriorating cVDPV epidemiology within the Horn of Africa, with concurrent humanitarian and different well being associated challenges. The committee famous ongoing substantial function of cell populations in sustaining the cVDPV transmission throughout a number of international locations. The committee additionally famous that context-specific tailor-made interventions shall be important to implement high-quality campaigns and in the end cease the cVDPV outbreaks within the present advanced situation, with various challenges in several international locations and sub-national geographies. Synchronized sub-regional approaches and robust cross-border coordination may even be important to collectively tackle the challenges referring to permeable borders and customary operational challenges throughout international locations. The committee encourages the international locations to doc and share the most effective practices and means that GPEI facilitates that.
The committee famous that novel OPV2 continues to display excessive genetic stability in comparison with Sabin OPV2. Nevertheless, the danger of latest cVDPV2 emergences will stay within the occasion of lengthy intervals (> 4 weeks) between outbreak response campaigns and low vaccination high quality.
The committee famous the continued provide associated challenges relating to novel OPV2 and is inspired by the prospects for enchancment throughout the second half of 2024, together with doable arrival of a second provider available in the market. The committee thought of that securing of vaccine provide was a important challenge and that there ought to be planning to make sure a extra sturdy vaccine provide past admission of a brand new provider. Whereas encouraging international locations to declare public well being emergencies following detection of a brand new outbreak, such essential actions must be supported by the GPEI in making certain vaccine availability.
The committee famous that 20 international locations within the African Area are but to introduce a second dose of IPV of their Routine Immunization schedules. Furthermore, a quantity cVDPV outbreak affected international locations proceed to have low IPV1 protection. It is very important take pressing steps to introduce IPV2 within the Routine Immunization of the remaining international locations and enhance IPV1 protection, particularly within the outbreak affected international locations. The committee is inspired by the prequalification of the Hexavalent Vaccine and availability of GAVI help for its introduction., beginning in 2025. The committee appreciates the GPEI plan on integration and encourages to take all steps to implement that and make the most of all doable alternatives to spice up inhabitants immunity in opposition to polio, together with the Massive Catch up.
The committee famous the continued GPEI efforts to keep up delicate surveillance for polioviruses, and that epidemiological and genetic knowledge signifies want for additional high quality enchancment within the WPV1 endemic international locations in addition to the cVDPV affected international locations. The Committee recommended to fast-track the efforts to enhance pace of detection to tell fast response, with particular deal with high-risk geographies and populationsThe committee famous the evaluate of the Worldwide Well being Rules and that amendments to the Rules had been doable in 2024 however that these haven’t but come into impact. The Committee felt it was nonetheless too early to discontinue the PHEIC as the danger of exportation of each WPV and cVDPVs stays important, noting additionally that there was geographical unfold of WPV1 within the Pakistan and Afghanistan epidemiological block in 2023 and 2024.
Primarily based on the present scenario relating to WPV1 and cVDPVs, and the reviews supplied by affected international locations, the Director-Common accepted the Committee’s evaluation and on 12 continues to represent a PHEIC with respect to WPV1 and cVDPV. The Director-Common endorsed the Committee’s suggestions for international locations assembly the definition for ‘States contaminated with WPV1, cVDPV1 or cVDPV3 with potential danger for worldwide unfold’, ‘States contaminated with cVDPV2 with potential danger for worldwide unfold’ and for ‘States beforehand contaminated by WPV1 or cVDPV throughout the final 24 months’ and prolonged the Non permanent Suggestions beneath the IHR to cut back the danger of the worldwide unfold of poliovirus, efficient, 12 August 2024.
