Statement of the 14th IHR Emergency Committee regarding the international spread of poliovirus

Report
from World Health Organization
Published on 03 Aug 2017 View Original

WHO statement 3 August 2017

The fourteenth 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 3 August 2017 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 24 April2017: Afghanistan, Democratic Republic of Congo (DR Congo), Nigeria, Pakistan and Syria.

Wild polio

Overall the Committee was encouraged by continued steady progress in all three WPV1 infected countries, Pakistan, Afghanistan, and Nigeria, and the fall in the number of cases globally, with no international spread detected in the last three months. While falling transmission in these three countries decreased the risk of international spread, the consequences should spread occur would represent a significant set-back to eradication and a risk to public health.

The Committee commended the efforts of Pakistan that has seen the number of cases fall to just three so far in 2017. However, WPV1 continues to be widespread geographically as detected by environmental surveillance although the intensity of environmental surveillance in the country is now very high meaning the probability of detection is higher than previous years. The Committee noted that accessibility has improved greatly and that the quality of supplementary immunization activities (SIA) continued to be better.

The Committee welcomed the reduction in the number of inaccessible children in Afghanistan. However, since the last committee meeting, new cases of wild poliovirus infection have occurred in Kandahar and Hilmand provinces, highlighting that the southern region of Afghanistan continues to have pockets of chronically missed children unreached by the polio program.

The level of cooperation along the international border between the two countries is very good. The main challenge is the shared poliovirus reservoirs between the two countries, within which there are high risk mobile populations such as nomadic groups, local populations that straddle the border, seasonal workers and their families, repatriating refugees (official and informal), and guest children (children staying with relatives across the border). This means coordination and cooperation is absolutely essential to achieve eradication, and the committee urged the two countries to continue and increase bilateral polio eradication activities.

The Committee noted that there were no new WPV1 cases detected in Nigeria since August 2016 but that there remains a substantial population in Borno state that is totally or partially inaccessible, including around 250,000 children. The committee concluded that there is a high risk that polioviruses are still circulating in these inaccessible areas. Reaching these populations is critically important for polio eradication, but it is acknowledged that there are significant security risks that may pose a danger to polio eradication workers and volunteers. Nigeria has already adopted innovative and multi-pronged approaches to this problem, and these innovations should be continued. Nigeria also reported on ongoing efforts to ensure vaccination at international borders (including at airports), other transit points, IDP camps and in other areas where nomadic populations existed, but these need to be further strengthened, including setting up permanent border vaccination posts wherever possible.

There was ongoing concern about the Lake Chad basin region, and for all the countries that are affected by the 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 high. The committee was encouraged that the Lake Chad basin countries including Nigeria, Cameroon, Chad, Niger and the Central African Republic (CAR), continued to be committed to sub-regional coordination of immunization and surveillance activities. However, significant gaps in population immunity exist in some areas of these countries in border areas with Borno.

Vaccine derived poliovirus

The committee was very concerned about the new outbreaks of type 2 cVDPV in DR Congo and Syria. These outbreaks highlighted the presence of vulnerable under-immunized populations in areas with inaccessibility, either due to conflict or geographical remoteness. Furthermore, the delay in detection of these outbreaks illustrated that serious gaps in surveillance exist in many areas of the world, often related to conflict and disruption to the health system.

Countries surrounding the outbreak zone are responding to the Syrian outbreak to prevent importation, particularly among Syrian refugees in Lebanon, Jordan, and Turkey. The committee urged any country receiving Syrian refugees, particularly from Deir Ez-Zor and Raqqa, to ensure polio vaccination with IPV where available. In DR Congo surveillance gaps need to be addressed with a comprehensive and sustained response.

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 revised 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 Syria.

  • 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 one of the world’s most serious vaccine preventable diseases. 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 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 high.

  • 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 heightens the risk of international spread considerably;

  • The ongoing circulation of cVDPV2 in Nigeria, Pakistan, Syria and DR Congo 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;

  • 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.

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 samples collected within 12 months of the last case have also tested negative, whichever is the longer.

  • Environmental isolation of WPV1 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

  • 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

  • Pakistan
  • Afghanistan
  • 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; 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).

  • These countries should 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.

  • 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

  • DR Congo
  • Nigeria
  • Pakistan
  • Syria

These countries should:

  • 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.

  • 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 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.

  • 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

WPV1

  • Cameroon (last case 9 July 2014)
  • Niger (last case 15 November 2012)
  • Chad (last case 14 June 2012)
  • Central African Republic (last case 8 December 2011)

cVDPV

  • Ukraine (last case 7 July 2015)
  • Madagascar (last case 22 August 2015)
  • Myanmar (last case 5 October 2015)
  • Guinea (last case 14 December 2015)
  • Lao PDR (last case 11 January 2016)

These countries should:

  • Urgently strengthen routine immunization to boost population immunity.

  • Enhance surveillance quality 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 12 months after the last case of WPV1 or cVDPV2, whichever is the latest, in the sub-region. Based on the last cases (above) reports will be due for Myanmar in November 2017, for Madagascar in September 2017, for Guinea in January 2018, and in Lao PDR February 2018. In the case of Ukraine, the committee noted that a final report had been provided, but was concerned that this report showed that the risk of WPV importation and cVDPV importation or emergence remained high, largely due to poor immunization coverage. The committee decided to maintain the country in this category, and requested a review of the situation at the next committee meeting.

Additional considerations

The Director-General Dr Tedros attended the Emergency Committee and listened to the recommendations of the committee. He thanked Committee Members and Advisors for their advice, and noted that in the context of polio eradication, even one case of polio should be treated as an emergency. He noted that in all the geographic areas reviewed by the committee at the meeting, a sub-regional or multi-country coordinated response greatly improved the chance of success, and that to achieve the final goal of zero cases, the world may need to respond even more aggressively. He affirmed that he was personally committed as Director-General to providing any support needed to reduce the risk of the international spread of polio recommended by the committee.

The Committee strongly urged global partners in polio eradication to provide optimal support to all infected and vulnerable countries at this critical time in the polio eradication programme for implementation of the Temporary Recommendations under the IHR, as well as providing ongoing support to all countries that were previously subject to Temporary Recommendations (Somalia, Ethiopia, Iraq, Israel and Equatorial Guinea).

The Committee urged all countries to avoid complacency which could easily lead to a resurgence of polio. Surveillance particularly needs careful attention to quickly detect any new transmission, and careful assessment of where insecurity and inaccessibility impact on surveillance was needed. Similarly, there needs to be tracking of populations where there are high proportions of unvaccinated children due to inaccessibility, and requested the secretariat to include a report on this issue at its next meeting.

Based on the current situation regarding WPV1 and cVDPV, and the reports made by Afghanistan, DR Congo, Nigeria, Pakistan, and Syria, the Director-General accepted the Committee’s assessment and on 3 August 2017 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 3 August 2017.