WHO Statement on the Fifth Meeting of the International Health Regulations (2005) Emergency Committee regarding the International Spread of Wild Poliovirus

Écrit par WHO | 10 Mai 2015

5 May 2015 - The fifth meeting of the Emergency Committee under the International Health Regulations (2005) (IHR) regarding the international spread of wild poliovirus in 2014 - 15 was convened via teleconference by the Director-General on 24 April 2015.  The following IHR States Parties submitted an update on the implementation of the Temporary Recommendations since the Committee last met on 17 February 2015: Afghanistan and Pakistan.

The Committee noted that after nearly one year 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  in response to the Temporary Recommendations issued by the Director-General, and that this was a commendable achievement. No cases of wild poliovirus have been reported in Africa for eight months; in 2015, Pakistan and Afghanistan have reported less than half the number of cases that were reported during the same period in 2014; there has been no exportation from Pakistan since October 2014; and the number of persistently missed and inaccessible children is declining in Pakistan.  The number of inaccessible children has declined from an estimated 300,000 to 50,000 in Federally Administered Tribal Areas.  Pakistan continued to implement the Temporary Recommendations; since November, an average of 370,000 international travellers per month were vaccinated pre-departure at health facilities and points of exit.

The Committee noted, however, that the international spread of wild poliovirus has continued with three new documented exportations from Afghanistan into neighbouring Pakistan which occurred in late 2014.  The poliovirus isolates found in the three cases in Pakistan were more closely related to strains recently circulating in Afghanistan than to those currently found in Pakistan.  While two of these virus strains circulated in bordering areas of Afghanistan following recent exportation from Pakistan (September 2014), the third virus was related to a strain that had circulated only in Afghanistan for a period of more than one year, thus demonstrating the strongest evidence of exportation into Pakistan of a strain of poliovirus that has established transmission in Afghanistan.   

The Committee agreed that Pakistan and Afghanistan formed a single epidemiological block with frequent cross-border population movement, which accounts for the ebb and flow of poliovirus in both directions.    Much stronger coordination and quality of cross-border vaccination and surveillance activities will be essential to reduce the risk of this international spread.  In addition, both countries must achieve interruption of poliovirus transmission simultaneously in order to prevent such international spread from repeatedly setting back progress in both countries.   

In Pakistan, a reduction of cases occurred during the low season and the performance of the eradication program has improved.  Nevertheless,  21 of 22 reported cases in 2015 to date (or 95% of global cases in 2015) were reported from Pakistan, and the key factors that contribute to international spread of wild poliovirus from Pakistan, although improving, have not changed sufficiently since the fourth meeting of the Emergency Committee on 17 February.  The risk of new exportations from Pakistan remains with the ongoing transmission in the country during the low transmission season, nearly 50,000 children still inaccessible in infected areas of the Federally Administered Tribal Areas and the imminent high transmission season that commences in May.  In Afghanistan, the number of cases reported has declined and cross-border transit vaccination activities have been strengthened, particularly in the Southeast Region.  However, areas with chronically missed or inaccessible populations remain in parts of Southern and Eastern Regions.

Despite the commendable progress, the implications of the continued risk of international spread from Pakistan and Afghanistan remain of concern.  This is a critical stage for global polio eradication during which the hard-earned gains can be quickly lost given fragility of progress and continued disruption of immunization systems in settings of conflict and complex humanitarian emergencies.    

Although the risk of new international spread from other infected Member States appears to have declined, the possibility of international spread still remains a global threat worsened by expansion of conflict-affected areas, particularly in the Middle East and Central Africa.  Countries affected by conflict are vulnerable to outbreaks of polio that can be difficult to detect and are very challenging and costly to control.

The Committee unanimously agreed that the spread of polio still constitutes 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:

1. The continued international spread of wild poliovirus through 2014, including during the low transmission season;
2. The risk and consequent costs of failure to eradicate globally one of the world’s most serious vaccine preventable diseases;
3. 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 with the onset of the high transmission season in May/June 2015;
4. The serious consequences of further international spread for the increasing number of countries in which immunization systems have been disrupted by conflict and complex emergencies. Populations in these fragile states are vulnerable to  outbreaks of polio which are exceedingly difficult to control;
5. The importance of a regional approach and strong cross-border cooperation, as much international spread of polio occurs over land borders.

The Committee sincerely appreciated the efforts that all countries have made in response to the Temporary Recommendations and reviewed the progress against the criteria previously established by the Committee for countries subject to Temporary Recommendations.  The Committee remains concerned that implementation of the Temporary Recommendations is incomplete in all affected countries, some of whom are affected by conflicts and other causes of instability and vulnerability.
The Committee provided the Director-General with the following advice aimed at reducing the risk of international spread of wild poliovirus, 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 wild poliovirus
Pakistan (last exportation: 21 October, 2014) and Afghanistan (exportation: 22 October, 2014)
These states 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) 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, which can be considered as one epidemiological block, 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 at least 12 months have passed without new exportations¹.

• 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 but not currently exporting

Cameroon (last case: 9 July 2014), Equatorial Guinea (last case: 3 May 2014, Nigeria (last case: 26 July 2014), Somalia (last case: 11 August 2014), and Iraq (last case: 7 April 2014)


These states 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 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 at least 12 months without evidence of transmission¹.

• 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.

The Committee noted that by 7 May and 4 June 2015, Iraq and Equatorial Guinea, respectively, should there be no further detection of wild poliovirus up to these dates¹, will meet the criteria for ‘States no longer infected by wild poliovirus, but which remain vulnerable to international spread.’


States no longer infected by wild poliovirus, but which remain vulnerable to international spread

Ethiopia (last case: 5 January 2014), Syria (last case: 5 January 2014), and Israel (last positive environmental sample: 30 March 2014).  As of 7 May and 3 June 2015¹, should there be no further cases, Iraq and Equatorial Guinea, respectively, will meet the criteria for this category of risk and should:

• Enhance surveillance quality to reduce the risk of undetected wild poliovirus 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 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 poliovirus, provide a report to the Director General on measures taken to implement the Temporary Recommendations.

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 program.  The Committee advised that in view of the evolving situation, particularly the imminent commencement of the high transmission season, periodic review and assessment of the risk of international spread and measures to mitigate these risks are warranted.
Based on this advice, the reports made by Afghanistan and Pakistan and the currently available information, the Director-General accepted the Committee’s assessment and on 5 May 2015 determined that the events continue to constitute a PHEIC.  The Director-General endorsed the Committee’s recommendations for ‘States currently exporting wild polioviruses’, for ‘States infected with wild poliovirus but not currently exporting’ and for ‘States no longer infected by wild poliovirus, but which remain vulnerable to international spread and extended them, as revised by the Committee, as Temporary Recommendations under the IHR to reduce the international spread of wild poliovirus, effective 5 May 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.

¹The 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 (table):
States no longer exporting (detection of no new wild poliovirus exportation):

• Wild 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.
• Environmental isolation of exported wild 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.

States no longer infected (detection of no new wild poliovirus):

• Wild 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.
• Environmental isolation of wild poliovirus: 12 months after collection of the most recent positive environmental sample PLUS one month to account for the laboratory testing and reporting period.