WHO Concludes 60th Meeting under IHR on Wild Poliovirus

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Geneva  (ABC Live); Wild Poliovirus : The sixteenth meeting of the Emergency Committee under the International Health Regulations (2005) (IHR) regarding the international spread of poliovirus was convened by the Director General on 7 February 2018 at WHO headquarters with members, advisers and invited member states attending via teleconference.

The Emergency Committee reviewed the data on wild poliovirus (WPV1) and circulating vaccine derived polioviruses (cVDPV). The Secretariat presented a report of progress for affected IHR States Parties subject to Temporary Recommendations. The following IHR States Parties presented an update on the current situation and the implementation of the WHO Temporary Recommendations since the Committee last met on 14 November 2017: Afghanistan, Democratic Republic of Congo (DR Congo), Nigeria, Pakistan and Syrian Arab Republic.

Wild polio

Overall the Committee was encouraged by continued progress in WPV1 eradication, with the number of cases globally falling to an all-time low in 2017. In addition, there has been no international spread of WPV since the fifteenth meeting in November 2017.

The Committee commended the continued high level commitment seen in both Afghanistan and Pakistan, and the high degree of cooperation and coordination, particularly targeting the high risk mobile populations that cross the international border, such as nomadic groups, local populations straddling the border, seasonal migrant workers and their families, repatriating refugees (official and informal), and guest children (children staying with relatives across the border). Stopping transmission in these populations remains a major challenge that cannot be under-estimated, underlining the critical continuing need for cross border activities in surveillance and vaccination.

The Committee commended the achievements in Pakistan that have resulted in the number of cases falling to just eight cases in 2017 and no cases so far in 2018; these achievements included the improved accessibility, improved communication to reduce missed children and better quality supplementary immunization activities (SIA). However, environmental surveillance continues to detect WPV1 transmission in many high risk areas of the country, with the highest rates of positive samples in Karachi, Peshawar and the Quetta Block. Orphan viruses (viruses that are not closely related to any other virus based on genetic analysis) were detected in Karachi, Kila Abdullah, Pishin and Punjab, indicating missed transmission and gaps in surveillance. The Committee was very saddened to learn of the murder of two front line polio workers in Quetta, and acknowledged the extraordinary commitment of the Pakistan program to carry on with eradication activities.

The Committee was concerned by the stagnation in progress in Afghanistan and the ongoing risks to eradication posed by the number of inaccessible and missed children, particularly in the southern region, resulting in fourteen cases in 2017, and already three cases in 2018. While inaccessibility can fluctuate over time, approximately 23,000 children are chronically unreached by the polio program. The current increase in violence and insecurity in parts of the country with consequent impact on all international program operations was of grave concern.

The Committee commended the innovations that continue to be made in Nigeria to reach children in Borno. While the number of inaccessible settlements has fallen, there still remains a substantial population in Borno state that is totally inaccessible, including around 160,000 children aged under five. While certain cross border activities are being undertaken, such as international synchronization of vaccination campaigns, these efforts appeared to be insufficient to ensure no poliovirus still circulating undetected is exported to neighboring Lake Chad basin countries. There also seemed to be signs of decreasing political commitment and increasing fatigue in fighting polio; the Federal Government only released 2017 funding for polio in early 2018, the Presidential Task Team had not met regularly, and the Nigeria Governors’ Forum is no longer actively involved in the polio programme. The Committee also noted that routine immunization coverage is low, particularly in high risk areas of northern Nigeria. The country however has declared routine immunization a national public health emergency and is actively planning for Gavi transition. Although it is over 16 months since the last detection of WPV1, the recent outbreak response assessment by global polio experts concluded ongoing undetected transmission could not be ruled out.

There is ongoing concern about the districts of the neighboring countries of the Lake Chad basin region that have been affected by the Boko Haram insurgency, with the consequent lack of services and presence of IDPs and refugees. The risk of international spread from Nigeria to the Lake Chad basin countries or further afield in sub-Saharan Africa remains substantial. The Committee was encouraged that the Lake Chad basin countries, Cameroon, Chad, the Central African Republic (CAR), Niger and Nigeria continued to be committed to sub-regional coordination of immunization and surveillance activities. However, there are widespread persistent gaps in population immunity across these countries, and the ongoing population movement in the sub-region and insecurity are major challenges.

Vaccine derived poliovirus

In DR Congo, there has been further transmission particularly in Tanganyika province, necessitating further rounds with mOPV2. Risks are compounded by poor surveillance in many areas, and widespread gaps in population immunity. The Committee was particularly concerned that the response had not been put on a sufficient emergency footing, and there was a lack of urgency in some aspects of the response, including apparent lack of attention to minimizing the risk of international spread. It was noted that upcoming elections with the possibility of civil unrest posed an additional risk to the ability of the country to halt the outbreak.

The Committee remains concerned by the size of cVDPV2 outbreak in Syrian Arab Republic but was encouraged by the efforts being made, noting the great difficulty in reaching all target populations because of the ongoing conflict. Although there is ongoing cross border coordination particularly with Lebanon, it remains unclear whether similar efforts are required and are being undertaken with other neighbouring countries. This is particularly important as poliovirus type 2 population immunity rapidly wanes globally, and the risk of spread beyond Syria’s borders will increase substantially, meaning urgent action is needed to stop transmission.

The Committee remained concerned about the recent detection of three highly diverged type 2 VDPV viruses in the sewage in Mogadishu in Somalia . With substantial areas inaccessible to vaccination, the mOPV2 and IPV response in December, January and February will need to be carefully assessed to determine if transmission has been interrupted.

Since the last committee meeting, there has been no new detection of cVDPV2 in Pakistan. As it is now over 16 months since the most recent cVDPV2 was detected, Pakistan no longer meets the criteria for a cVDPV2 infected country. However, based on the outbreak assessment in Nigeria, ongoing transmission could not be ruled out.

Conclusion

The Committee unanimously agreed that the risk of international spread of poliovirus remains a Public Health Emergency of International Concern (PHEIC), and recommended the extension of Temporary Recommendations for a further three months. The Committee considered the following factors in reaching this conclusion:

  • The potential risk of further spread through population movement, whether for family, social or cultural reasons, or in the context of populations displaced by insecurity, returning refugees, or nomadic populations, and the need for international coordination to address these risks, particularly between Afghanistan and Pakistan, Nigeria and its Lake Chad neighbors, and countries bordering the Syrian Arab Republic.
  • The current special and extraordinary context of being closer to polio eradication than ever before in history, with the incidence of WPV1 cases in 2017 the lowest ever recorded.
  • The risk and consequent costs of failure to eradicate globally a highly debilitating vaccine preventable disease. Even though global transmission of WPV1 has fallen dramatically and with it the likelihood of international spread, the consequences and impact of international spread should it occur now would be even more grave and a major set-back to achieving eradication.
  • The risk of global complacency developing as the numbers of polio cases continues to fall and eradication becomes a tangible reality soon.
  • The outbreak of WPV1 (and cVDPV) in Nigeria highlighting that there are high-risk areas where surveillance is compromised by inaccessibility, resulting in ongoing circulation of WPV for several years without detection. The risk of transmission in the Lake Chad sub-region appears considerable.
  • The serious consequences of further international spread for the increasing number of countries in which immunization systems have been weakened or disrupted by conflict and complex emergencies. Populations in these fragile states are vulnerable to outbreaks of polio. Outbreaks in fragile states are exceedingly difficult to control and threaten the completion of global polio eradication during its end stage.
  • The importance of a regional approach and strong cross­border cooperation, as much international spread of polio occurs over land borders, while also recognizing that the risk of distant international spread remains from zones with active poliovirus transmission.
  • Additionally with respect to cVDPV:
    • cVDPVs also pose a risk for international spread, which without an urgent response with appropriate measures threatens vulnerable populations as noted above;
    • The large number of cases in the Syrian outbreak within a short space of time and close to the international border with Iraq in the context of ongoing population movement because of conflict, considerably heightens the risk of international spread;
    • The ongoing circulation of cVDPV2 in DR Congo, and the Syrian Arab Republic demonstrates significant gaps in population immunity at a critical time in the polio endgame;
    • The ongoing urgency to prevent type 2 cVDPVs following the globally synchronized withdrawal of the type 2 component of the oral poliovirus vaccine in April 2016, noting that population immunity to type 2 polioviruses is rapidly waning in many countries;
    • The ongoing challenges of improving routine immunization in areas affected by insecurity and other emergencies;
    • The global shortage of IPV which poses an additional risk, in that the cohort of children with no type 2 immunity is growing in number in countries affected by the shortage.

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:

  • States infected with WPV1, cVDPV1 or cVDPV3, with potential risk of international spread.
  • States infected with cVDPV2, with potential risk of international spread.
  • States no longer infected by WPV1 or cVDPV, but which remain vulnerable to re-infection by WPV or cVDPV.

Criteria to assess States as no longer infected by WPV1 or cVDPV:

  • Poliovirus Case: 12 months after the onset date of the most recent case PLUS one month to account for case detection, investigation, laboratory testing and reporting period OR when all reported AFP cases with onset within 12 months of last case have been tested for polio and excluded for WPV1 or cVDPV, and environmental or other samples collected within 12 months of the last case have also tested negative, whichever is the longer.
  • Environmental or other isolation of WPV1 or cVDPV (no poliovirus case): 12 months after collection of the most recent positive environmental or other sample (such as from a healthy child) PLUS one month to account for the laboratory testing and reporting period.
  • These criteria may be varied for the endemic countries, where more rigorous assessment is needed in reference to surveillance gaps (eg Borno)

Once a country meets these criteria as no longer infected, the country will be considered vulnerable for a further 12 months. After this period, the country will no longer be subject to Temporary Recommendations, unless the Committee has concerns based on the final report.

TEMPORARY RECOMMENDATIONS

States infected with WPV1, cVDPV1 or cVDPV3 with potential risk of international spread

  • Afghanistan
  • Pakistan
  • Nigeria

These countries should:

  • Officially declare, if not already done, at the level of head of state or government, that the interruption of poliovirus transmission is a national public health emergency and implement all required measures to support polio eradication; where such declaration has already been made, this emergency status should be maintained.
  • Ensure that all residents and long­term visitors (i.e. > four weeks) of all ages, receive a dose of bivalent oral poliovirus vaccine (bOPV) or inactivated poliovirus vaccine (IPV) between four weeks and 12 months prior to international travel.
  • Ensure that those undertaking urgent travel (i.e. within four weeks), who have not received a dose of bOPV or IPV in the previous four weeks to 12 months, receive a dose of polio vaccine at least by the time of departure as this will still provide benefit, particularly for frequent travelers..
  • Ensure that such travelers are provided with an International Certificate of Vaccination or Prophylaxis in the form specified in Annex 6 of the IHR to record their polio vaccination and serve as proof of vaccination.
  • Restrict at the point of departure the international travel of any resident lacking documentation of appropriate polio vaccination. These recommendations apply to international travelers from all points of departure, irrespective of the means of conveyance (e.g. road, air, sea).
  • Further intensify cross­border efforts by significantly improving coordination at the national, regional and local levels to substantially increase vaccination coverage of travelers crossing the border and of high risk cross­border populations. Improved coordination of cross­border efforts should include closer supervision and monitoring of the quality of vaccination at border transit points, as well as tracking of the proportion of travelers that are identified as unvaccinated after they have crossed the border.
  • Further intensify efforts to increase routine immunization coverage, including sharing coverage data, as high routine immunization coverage is an essential element of the polio eradication strategy, particularly as the world moves closer to eradication.
  • Maintain these measures until the following criteria have been met: (i) at least six months have passed without new infections and (ii) there is documentation of full application of high quality eradication activities in all infected and high risk areas; in the absence of such documentation these measures should be maintained until the state meets the above assessment criteria for being no longer infected.
  • Provide to the Director-General a regular report on the implementation of the Temporary Recommendations on international travel.

States infected with cVDPV2s, with potential risk of international spread

  • Democratic Republic of the Congo
  • Nigeria
  • Syrian Arab Republic

These countries should:

  • Officially declare, if not already done, at the level of head of state or government, that the interruption of poliovirus transmission is a national public health emergency and implement all required measures to support polio eradication; where such declaration has already been made, this emergency status should be maintained.
  • Noting the existence of a separate mechanism for responding to type 2 poliovirus infections, consider requesting vaccines from the global mOPV2 stockpile based on the recommendations of the Advisory Group on mOPV2
  • Encourage residents and long­term visitors to receive a dose of IPV (if available in country) four weeks to 12 months prior to international travel; those undertaking urgent travel (i.e. within four weeks) should be encouraged to receive a dose at least by the time of departure.
  • Ensure that travelers who receive such vaccination have access to an appropriate document to record their polio vaccination status.
  • Intensify regional cooperation and cross­border coordination to enhance surveillance for prompt detection of poliovirus, and vaccinate refugees, travelers and cross­border populations, according to the advice of the Advisory Group.
  • Further intensify efforts to increase routine immunization coverage, including sharing coverage data, as high routine immunization coverage is an essential element of the polio eradication strategy, particularly as the world moves closer to eradication.
  • Maintain these measures until the following criteria have been met: (i) at least six months have passed without the detection of circulation of VDPV2 in the country from any source, and (ii) there is documentation of full application of high quality eradication activities in all infected and high risk areas; in the absence of such documentation these measures should be maintained until the state meets the criteria of a ‘state no longer infected’.
  • At the end of 12 months without evidence of transmission, provide a report to the Director-General on measures taken to implement the Temporary Recommendations.

States no longer infected by WPV1 or cVDPV, but which remain vulnerable to re-infection by WPV or cVDPV

  • Cameroon (last case 9 Jul 2014)
  • Central African Republic (last case 8 Dec 2011)
  • Chad (last case 14 Jun 2012)
  • Niger (last case 15 Nov 2012)

These countries should:

  • Urgently strengthen routine immunization to boost population immunity.
  • Enhance surveillance quality, including considering introducing supplementary methods such as environmental surveillance, to reduce the risk of undetected WPV1 and cVDPV transmission, particularly among high risk mobile and vulnerable populations.
  • Intensify efforts to ensure vaccination of mobile and cross­border populations, Internally Displaced Persons, refugees and other vulnerable groups.
  • Enhance regional cooperation and cross border coordination to ensure prompt detection of WPV1 and cVDPV, and vaccination of high risk population groups.
  • Maintain these measures with documentation of full application of high quality surveillance and vaccination activities.
  • At the end of 12 months* without evidence of reintroduction of WPV1 or new emergence and circulation of cVDPV, provide a report to the Director-General on measures taken to implement the Temporary Recommendations.

*For the Lake Chad countries, this will be linked to when Nigeria is considered no longer infected by WPV1 or cVDPV2.

Additional considerations

The Committee noted that in all the infected and vulnerable countries, routine immunization was generally quite poor, if not nationally, then in sub-national pockets. The Committee also noted that surveillance in these areas may also be sub-optimal, particularly where access is compromised by conflict. The Committee strongly encourages all these countries to make further efforts to improve routine immunization and strengthen surveillance in such areas, and requested international partners to support these countries in rapidly improving routine immunization coverage to underpin eradication.

The Committee also urged that Nigeria and the Lake Chad countries increase cross border efforts and joint planning and response. Intensified effort is needed to identify and reach vulnerable populations in the sub-region, particularly in the Lake Chad islands. Noting the low number of international travelers being vaccinated in Nigeria, the committee again recommended that the country needs to improve implementation of the Temporary Recommendations regarding traveler vaccination, including reporting of achievements, and requests the secretariat to report back on this aspect of Nigeria’s response to the next Committee meeting. Nigeria should ensure continuing political commitment and take measures to counter fatigue in the fight against polio. Similarly, the DR Congo government needs to regard the current outbreak of cVDPV2 as a public health emergency and pay more attention to prevention of international spread of cVDPV2 from DR Congo, noting that neighboring countries are affected by the global shortage of IPV.

Noting the issues that continue in countries previously subject to Temporary Recommendations such as the Ukraine and Somalia, the Committee requested the secretariat to continue to monitor these and other previously infected countries, and highlight to the Committee issues that pose a risk of international spread. The Committee requested an update on the situation in Somalia at its next meeting.

Based on the current situation regarding WPV1 and cVDPV, and the reports made by Afghanistan, DR Congo, Nigeria, Pakistan, and the Syrian Arab Republic, the Director-General accepted the Committee’s assessment and on 13 February 2018 determined that the situation relating to poliovirus continues to constitute a 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 no longer infected by WPV1 or cVDPV, but which remain vulnerable to re-infection by WPV or cVDPV’ and extended the Temporary Recommendations under the IHR to reduce the risk of the international spread of poliovirus, effective 13 February 2018.