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Statement on the 8th IHR Emergency Committee meeting regarding the international spread of poliovirus

WHO statement
1 March 2016

The eighth 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 12 February 2016. As with the seventh meeting, the Emergency Committee reviewed the data on circulating wild poliovirus as well as circulating vaccine-derived polioviruses (cVDPV). The latter is particularly important as cVDPVs reflect serious gaps in immunity to poliovirus due to weaknesses in routine immunization coverage in otherwise polio-free countries. In addition, it is essential to stop type 2 cVDPVs 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 10 November 2015: Afghanistan, Pakistan and Guinea.

Wild polio

The Committee noted that since the declaration that the international spread of polio constituted a Public Health Emergency of International Concern (PHEIC) in May 2014, strong progress has been made by countries toward interruption of wild poliovirus transmission and implementation of Temporary Recommendations issued by the Director-General. There has been an overall decline in the occurrence of international spread of wild poliovirus. The Committee was particularly encouraged by the intensified efforts and progress toward interruption of poliovirus transmission in Pakistan and Afghanistan despite challenging circumstances, and the renewed emphasis on cooperation along the long international border between the two countries.

The Committee noted however that the international spread of wild poliovirus has continued, with two new recent reports of exportations from Pakistan into Afghanistan which occurred in October and November 2015. These cases occurred in Nangarhar and Kunar Provinces, in the eastern region, adjoining the Pakistan border. 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 ongoing spread between the two countries is occurring from discrete zones of persistent transmission in each country. Strong programmatic action in these zones should interrupt such cross-border transmission, as illustrated by the experience in regions that were previously polio-endemic.

The committee re-emphasized that under the IHR, spread of poliovirus between two Member States can constitute international spread. The Committee acknowledged that cross border collaboration efforts have continued to be strengthened. Whilst border vaccination between these two countries is limited to children under ten years of age, efforts are being made to vaccinate departing travellers of all age groups from airports when leaving this epidemiological block formed by the two countries. The committee was particularly pleased that the Temporary Recommendations for international travellers of all ages are now being implemented in Afghanistan at the international airport in Kabul. In this respect, it noted that all countries, and particularly those with embassies in Afghanistan and Pakistan, should facilitate implementation of Temporary Recommendations through adopting procedures that include proof of polio vaccination as part of visa application processes for travellers departing from Afghanistan or Pakistan.

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 of the GPEI 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.

The committee was very concerned by the weakening of AFP surveillance in Equatorial Guinea, and urged renewed efforts to strengthen surveillance and routine immunization there. Insecurity in Africa, notably in parts of Cameroon and Somalia, continues to pose a threat to polio eradication in that continent.

Vaccine derived poliovirus

The current circulating vaccine-derived poliovirus (cVDPV) outbreaks across four WHO regions illustrate serious gaps in routine immunization programs, leading to significant pockets of vulnerability to polio outbreaks. In 2015, six outbreaks of circulating vaccine derived poliovirus have occurred – three cVDPV type 1 outbreaks (Ukraine, Madagascar and Lao People’s Democratic Republic) and three cVDPV type 2 outbreaks (Myanmar, Nigeria and Guinea).

Six additional cases of cVDPV type 2 have been reported in Guinea since the last meeting. This increases the threat of international spread, particularly to neighbouring countries, where the Ebola epidemic has weakened health systems including routine immunization. This is of particular concern given the imminent global withdrawal of type 2 oral polio vaccine (OPV2) in April 2016. The committee noted with concern that AFP surveillance does not meet international standards in parts of Guinea, heightening concern about whether circulation could be missed. Post-Ebola there was a new community reluctance to accept vaccination, and this needs to be urgently addressed. The committee acknowledged the efforts to improve the quality of supplementary immunization activities (SIAs), and urged that this continue.

The committee noted that in Lao People’s Democratic Republic and Myanmar there was ongoing circulation of vaccine derived polioviruses, particularly in hard to reach populations in both countries, underlining the importance of communication to counteract vaccine hesitancy.

While there have been no new cases of cVDPV in Ukraine, Madagascar, South Sudan or Nigeria since the last committee meeting, threats remain. More needs to be done in each of these countries to improve routine coverage and AFP surveillance. In Ukraine, the committee was concerned by the restricted availability of polio vaccines (including non-availability to persons >10 years of age) and suboptimal routine immunization, and reports of lack of community acceptance of polio vaccines. This reluctance to be vaccinated needs to be addressed through well-crafted communications. In South Sudan and Nigeria, there was heightened risk of further circulation in areas affected by conflict and insecurity. Complacency is another risk in Nigeria, and as the number of SIAs decreases, the strengthening of routine immunization needs to be a high priority.

Conclusion

The Committee unanimously agreed that the international spread of polio remains a Public Health Emergency of International Concern (PHEIC) and recommended the extension of the Temporary Recommendations for a further three months. The Committee considered the factors expressed in reaching this conclusion at the seventh meeting still applied:

  • 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 VDPVs in four WHO regions demonstrates significant gaps in population immunity at a critical time in the polio endgame;
    • There is a particular urgency of stopping type 2 cVDPVs in advance of the globally synchronized withdrawal of type 2 component of the oral poliovirus vaccine in April 2016.

Risk categories

The Committee provided the Director-General with the following advice aimed at reducing the risk of international spread of wild poliovirus and cVDPVs, based on the risk stratification as follows:

Wild poliovirus

  • 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.

Circulating vaccine derived poliovirus

  • 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 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:

Criteria to assess States no longer exporting (detection of no new wild poliovirus or cVDPV exportation)

  • 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.

Criteria to assess States no longer infected (detection of no new wild poliovirus 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 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

Temporary recommendations

States currently exporting wild poliovirus or cVDPV

(Currently Pakistan (last wild poliovirus exportation: 3rd November 2015) and Afghanistan (last wild poliovirus exportation: 6 June 2015).

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.

States infected with wild poliovirus or cVDPVs but not currently exporting

(Currently Nigeria, Guinea, Madagascar, Ukraine, Lao People’s Democratic Republic and Myanmar)


Country Virus type # cases since outbreak began Most recent onset
Nigeria cVDPV2 1 16th May 2015
Ukraine cVDPV1 2 7th July 2015
Guinea cVDPV2 8 14th December 2015
Madagascar cVDPV1 11 22nd August 2015
Lao People’s Democratic Republic cVDPV1 10 11th January 2016
Myanmar cVDPV2 2 5th October 2015

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.
  • 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.

States no longer infected by wild poliovirus or cVDPV, but which remain vulnerable to international spread, and states that are vulnerable to the emergence and circulation of VDPV

(Currently Somalia, Iraq, Israel, Equatorial Guinea, Cameroon and South Sudan)

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:


Country Most recent case onset / +ve environmental isolate Final Report due
Israel 30-Mar-14 Apr-16
Iraq 7-Apr-14 May-16
South Sudan 19-Apr-15 May-16
Equatorial Guinea 3-May-14 Jun-16
Cameroon 9-Jul-14 Aug-16
Nigeria 16-May-2015* Aug-16
Somalia 11-Aug-14 Sep-16
* most recent cVDPV2 in Nigeria

Additional considerations for all infected countries

The Committee strongly urged global partners in polio eradication to provide optimal support to all infected countries at this critical time in the polio eradication 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 illustrates serious gaps in routine immunization programs in otherwise polio free countries, the Committee recommended that the international partners in routine immunization, for example Gavi, should urgently assist affected countries to improve the national immunization program.

The Committee again 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 cVDPV, and the reports made by Afghanistan, Pakistan, and Guinea, the Director-General accepted the Committee’s assessment and on 26 February 2016 determined that the events relating to poliovirus continue to constitute a PHEIC, with respect to wild poliovirus and 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 26 February 2016.

The Director-General thanked the Committee Members and Advisors for their advice and requested their reassessment of this situation within the next three months.