Statement on the Seventh IHR Emergency Committee meeting regarding the international spread of poliovirus
The seventh meeting of the Emergency Committee under the International Health Regulations (2005) (IHR) regarding the international spread of poliovirus was convened via teleconference by the Director-General on 10 November 2015. The Director General of WHO had noted the concerns expressed by the Emergency Committee in its August 2015 report with respect to circulating vaccine-derived polioviruses (cVDPV). In response, she convened this meeting of the Emergency Committee with broader terms than was previously the case to also look at outbreaks of cVDPV. During the current polio endgame cVDPVs reflect serious gaps in immunity to poliovirus due to weaknesses in routine immunization coverage in otherwise polio-free countries. Moreover, there is a particular urgency to stopping type 2 cVDPV in advance of the globally synchronized withdrawal of type 2 OPV in April 2016.
The following IHR States Parties submitted an update on the implementation of the Temporary Recommendations since the Committee last met on 4 August 2015: Afghanistan and Pakistan. The following IHR State Parties were invited to present their views to the committee and all except South Sudan submitted reports on measures and plans to stop circulating vaccine derived poliovirus: Nigeria, Guinea, Madagascar, Ukraine and Lao People’s Democratic Republic.
The Committee noted that since the declaration that the international spread of polio constituted a Public Health Emergency of International Concern (PHEIC), strong progress has been made by countries toward interruption of wild poliovirus transmission, implementation of Temporary Recommendations issued by the Director-General, and overall decline in occurrence of international spread of wild poliovirus. The Committee appreciated these commendable achievements. The Committee acknowledged the strong efforts of countries in Africa to eradicate polio noting that no cases of wild poliovirus have been reported in Africa for more than twelve months, and that Nigeria has interrupted endemic transmission of wild poliovirus. The Committee was particularly encouraged by the intensified efforts and the strong progress toward interruption of poliovirus in Pakistan and Afghanistan.
The Committee noted however that the international spread of wild poliovirus has continued, with two new documented exportations from Pakistan into Afghanistan which occurred in July and August 2015. The poliovirus isolates found in the two cases in Afghanistan were more closely related to strains recently circulating in Pakistan than to those currently found in Afghanistan. Both of these cases occurred in Achin district of Nangarhar Province, adjacent to the border with Pakistan. While there has been no new exportation from Afghanistan to Pakistan, ongoing transmission particularly in inaccessible parts of the Eastern Region of Afghanistan close to the international border presents an ongoing risk.
The Committee noted that while Pakistan and Afghanistan have historically shared a vast common zone of poliovirus transmission, the recent spread between the two countries is occurring from discrete zones of persistent transmission in each country. Strong programmatic action in such zones should interrupt such cross-border transmission, as illustrated by the experience in regions that were previously endemic for polio. The committee re-emphasized that under the IHR, spread of poliovirus between two Member States can constitute international spread. While the Committee appreciated that efforts are being made for cross border collaboration, the committee noted and concurred with the recent recommendation of the Independent Monitoring Board (IMB) of the Global Polio Eradication Initiative (GPEI). The IMB has recommended that the GPEI partners should help the governments of Pakistan and Afghanistan to establish a joint executive and planning body to instigate cross-border polio prevention and control. The committee was pleased that the Temporary Recommendations for international travellers of all ages are now being implemented in Afghanistan at the international airport in Kabul.
The committee noted that globally there are still significant vulnerable areas and populations that are inadequately immunized due to conflict, insecurity and poor coverage associated with weak immunization programmes. Such vulnerable areas include countries in the Middle East, the Horn of Africa, central Africa and parts of Europe. The hard-earned gains can be quickly lost if there is re-introduction of poliovirus in settings of disrupted health systems and complex humanitarian emergencies. The large population movements across the Middle East and from Afghanistan and Pakistan create a heightened risk of international spread of polio. There is a risk of missing polio vaccination among refugee and mobile populations, adding to missed and under vaccinated populations in Europe, the Middle East and Africa. An estimated three to four million people have been displaced to Turkey, Lebanon, and Jordan and are at the centre of a mass migration across Europe.
Vaccine Derived Poliovirus
The current cVDPV outbreaks across three WHO regions illustrate serious gaps in routine immunization programs of affected countries leading to large pockets of vulnerability to polio outbreaks. In 2015, five outbreaks of circulating vaccine derived poliovirus have occurred, three cVDPV1 outbreaks (Ukraine, Madagascar and Lao People’s Democratic Republic) and two cVDPV2 outbreaks (Nigeria and Guinea); furthermore an additional case of VDPV2 in a conflict-affected state of South Sudan is of concern.
There has been no international exportation of cVDPV during 2014 and 2015. Nonetheless, at least five past episodes of international spread of cVDPV have been recorded, all due to cVDPV type 2. While historically the overall risk of international spread of cVDPV appears to be lower than WPV, lack of adequate measures to control cVDPV can increase that risk.
The committee was concerned by the slow initial response in Ukraine and Madagascar, but encouraged that the response is improving in both countries. Additional efforts are needed to improve SIA quality in both countries. The committee also noted that targeted communication and strong engagement of communities were needed in Ukraine and Lao People’s Democratic Republic to overcome vaccine hesitancy, and that GPEI should assist with development of appropriate communications strategies and materials. The significant decline in immunization rates and AFP surveillance in Guinea and neighbouring Liberia and Sierra Leone due to the health system disruption caused by Ebola outbreak poses a risk for further spread of cVDPV, and the committee urged international partners to increase support to Guinea in its cVDPV outbreak response. Moreover, the testing of samples from AFP cases should be restored immediately and the overall systems for surveillance and immunization should be strengthened as soon as possible in the three Ebola-affected countries. The committee emphasized the importance of maintaining the quality of the programme along with strong political and civic engagement until global certification of polio eradication.
The Committee unanimously agreed that the international spread of polio remains a PHEIC and recommended the extension of the Temporary Recommendations, as revised, for a further three months. The Committee considered the following factors in reaching this conclusion:
- The continued international spread of wild poliovirus during 2015 involving Pakistan and Afghanistan.
- The risk and consequent costs of failure to eradicate globally one of the world’s most serious vaccine preventable diseases.
- The continued necessity of a coordinated international response to improve immunization and surveillance for wild poliovirus, stop its international spread and reduce the risk of new spread.
- 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 cross-border cooperation, as much international spread of polio occurs over land borders, while 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, and if there is no urgent response with appropriate measures, particularly threaten vulnerable populations as noted above;
- The emergence and circulation of VDPV in three WHO regions, underline significant gaps in population immunity at a critical time in the polio endgame, potentially threatening successful completion of global polio eradication;
- There is a particular urgency of stopping type 2 cVDPV in advance of the globally synchronized withdrawal of type 2 component of the oral poliovirus vaccine in April 2016.
The Committee provided the Director-General with the following advice aimed at reducing the risk of international spread of wild poliovirus and cVDPV, based on the risk stratification as follows:
- States currently exporting wild poliovirus;
- States infected with wild poliovirus but not currently exporting;
- States no longer infected by wild poliovirus, but which remain vulnerable to international spread.
- States currently exporting cVDPV;
- States infected with cVDPV but not currently exporting;
- States no longer infected by cVDPV, but which remain vulnerable to the emergence and circulation of VDPV.
The Committee updated and applied the following criteria to assess the period for detection of no new exportations and the period for detection of no new cases or environmental isolates of wild poliovirus or cVDPV:
- Poliovirus Case: 12 months after the onset date of the first case caused by the most recent exportation 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 the first case caused by the most recent importation have been tested for polio and excluded for newly imported WPV1 or cVDPV, and environmental samples collected within 12 months of the first case have also tested negative, whichever is the longer.
- Environmental isolation of exported poliovirus: 12 months after collection of the first positive environmental sample in the country that received the new exportation PLUS one month to account for the laboratory testing and reporting period.
- 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 samples collected within 12 months of the last case have also tested negative, whichever is the longer.
- Environmental isolation of wild poliovirus or cVDPV (no poliovirus case): 12 months after collection of the most recent positive environmental sample PLUS one month to account for the laboratory testing and reporting period
Exporting 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; where such declaration has already been made, this emergency status should be maintained.
- Ensure that all residents and long-term visitors (i.e. > four weeks) of all ages, receive a dose of oral poliovirus vaccine (OPV) 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 OPV 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 travellers.
- Ensure that such travellers 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 travellers from all points of departure, irrespective of the means of conveyance (e.g. road, air, sea).
- Recognising that the movement of people across the border between Pakistan and Afghanistan continues to facilitate exportation of wild poliovirus, both countries should further intensify cross-border efforts by significantly improving coordination at the national, regional and local levels to substantially increase vaccination coverage of travellers crossing the border and of high risk cross-border populations. Both countries have maintained permanent vaccination teams at the main border crossings for many years. Improved coordination of cross-border efforts should include closer supervision and monitoring of the quality of vaccination at border transit points, as well as tracking of the proportion of travellers that are identified as unvaccinated after they have crossed the border.
- Maintain these measures until the following criteria have been met: (i) at least six months have passed without new exportations 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 criteria of a ‘state no longer exporting’.
- Provide to the Director-General a monthly report on the implementation of the Temporary Recommendations on international travel, including the number of residents whose travel was restricted and the number of travellers who were vaccinated and provided appropriate documentation at the point of departure.
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; where such declaration has already been made, this emergency status should be maintained.
Country Virus type # cases since outbreak began Most recent onset Nigeria cVDPV2 1 16th May 2015 Ukraine cVDPV1 2 7th July 2015 Guinea cVDPV2 2 20th July 2015 Madagascar cVDPV1 11 22nd August 2015 Lao People’s Democratic Republic cVDPV1 3 7th October 2015
- Encourage residents and long-term visitors to receive a dose of OPV or IPV 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 travellers who receive such vaccination have access to an appropriate document to record their polio vaccination status.
- Intensify regional cooperation and cross-border coordination to enhance surveillance for prompt detection of poliovirus and substantially increase vaccination coverage among refugees, travellers and cross-border populations.
- Maintain these measures until the following criteria have been met: (i) at least six months have passed without the detection of wild poliovirus transmission or circulation of VDPV 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.
These countries should:
- Urgently strengthen routine immunization to boost population immunity.
- Enhance surveillance quality to reduce the risk of undetected wild poliovirus and cVDPV transmission, particularly among high risk mobile and vulnerable populations.
- Intensify efforts to ensure vaccination of mobile and cross-border populations, Internally Displaced Persons, refugees and other vulnerable groups.
- Enhance regional cooperation and cross border coordination to ensure prompt detection of wild poliovirus 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 wild poliovirus or new emergence and circulation of cVDPV, provide a report to the Director General on measures taken to implement the Temporary Recommendations.
GPEI and other international organizations, particularly Gavi, should provide all necessary support to reduce the risk of emergence and circulation of VDPV.
These countries should provide a final report as per the table below:
Most recent case onset / +ve environmental isolate
Final Report due
Syrian Arab Republic
The Committee strongly urged global partners in polio eradication to provide optimal support to all infected countries at this critical time in the program for implementation of the Temporary Recommendations under the IHR. The Committee advised that in view of the evolving situation, periodic review and assessment of the risk of international spread and measures to mitigate these risks are warranted.
The Committee recommended that international partners assist countries affected by cVDPV with development of appropriate communications strategies and materials to ensure clear public understanding of cVDPV, their distinction from wild poliovirus and maintenance of confidence in the effectiveness, safety and necessity of polio vaccines during the polio endgame. Recognizing that cVDPV illustrate serious gaps in routine immunization programs in otherwise polio free countries, the Committee recommended that the international partners in routine immunization, for example the Gavi Alliance, should urgently assist affected countries to improve the national immunization program.
The Committee requested the Secretariat to conduct an analysis of the public health benefits and costs of implementing the temporary recommendation requiring exporting countries to vaccinate all international travellers before departure.
Based on the advice concerning wild poliovirus and circulating VDPV, the reports made by Afghanistan, Pakistan, Nigeria, Madagascar, Guinea, Ukraine and Lao People’s Democratic Republic and the currently available information, the Director-General accepted the Committee’s assessment and on 25 November 2015 determined that the events relating to poliovirus continue to constitute a PHEIC, including with respect to cVDPV. The Director-General endorsed the Committee’s recommendations for ‘States currently exporting wild polioviruses or cVDPV’, for ‘States infected with wild poliovirus or cVDPV but not currently exporting’ and for ‘States no longer infected by wild poliovirus, but which remain vulnerable to international spread, and states that are vulnerable to the emergence and circulation of VDPV’ and extended the Temporary Recommendations as revised by the Committee under the IHR to reduce the international spread of poliovirus, effective 25 November 2015.
The Director-General thanked the Committee Members and Advisors for their advice and requested their reassessment of this situation within the next three months.