Statement of the twenty-fifth polio IHR Emergency Committee

Wild poliovirus

Vaccine derived poliovirus (VDPV)

Impact of COVID-19

Conclusion

• Rising risk of WPV1 international spread: The progress made in recent years appears to have reversed, with the Committee’s assessment that the risk of international spread is at the highest point since 2014 when the PHEIC was declared. This risk assessment is based on the following:

• the ongoing WPV1 exportation from Pakistan to Afghanistan, and from Afghanistan to Pakistan;
• ongoing rise in the number of WPV1 cases and positive environmental samples in both Pakistan and
  Afghanistan with formerly polio free areas within the countries reporting cases in 2020;
• the quickly increasing cohort of inaccessible unvaccinated children in Afghanistan, with the risk of a major
  outbreak imminent if nothing is done to access them;
• the urgent need to overhaul the leadership and strategy of the program in Pakistan, which although already commenced, is likely take some time to lead to more effective control of transmission and ultimately eradication;
• increasing community and individual resistance to the polio program.

• Rising risk of cVDPV international spread: The clearly documented increased spread in recent months of cVDPV2 demonstrate the unusual nature of the current situation, as international spread of cVDPV in the past has been very infrequent.  The number of new emergences of cVDPV2 in Africa raises further concern.  The risk of new outbreaks in new countries is considered very high.  
• COVID-19:  This unprecedented pandemic is likely to continue to substantially negatively impact the polio eradication program and outbreak control efforts.  The need to take extra precautions to prevent COVID-19 transmission will probably have an impact on vaccination coverage, and also hamper polio surveillance activities leading to increased risk of missed transmission.  
• Falling PV2 immunity:  Global population mucosal immunity to type 2 polioviruses (PV2) continues to fall, as the cohort of children born after OPV2 withdrawal grows, exacerbated by poor coverage with IPV particularly in some of the cVDPV infected countries.
• Multiple outbreaks: The evolving and unusual epidemiology resulting in rapid emergence and evolution of cVDPV2 strains is extraordinary and not yet fully understood and represents an additional risk that is yet to be quantified.
• Weak routine immunization: Many countries have weak immunization systems that can be further impacted by various humanitarian emergencies including COVID19, and the number of countries in which immunization systems have been weakened or disrupted by conflict and complex emergencies poses a growing risk, leaving populations in these fragile states vulnerable to outbreaks of polio. 
• Lack of access: Inaccessibility continues to be a major risk, particularly in several countries currently infected with WPV or cVDPV, i.e. Afghanistan, Nigeria, Niger, Somalia and Myanmar, which all have sizable populations that have been unreached with polio vaccine for prolonged periods.
• Population movement: While border closures may have mitigated the short term risk, conversely the risk once borders begin to be re-opened is likely to be higher.  

Risk categories

• 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.

• 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 (e.g. Borno State, Nigeria)

TEMPORARY RECOMMENDATIONS

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

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 as long as the response is required.
• 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 cross­ border 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 cross ­border populations. 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 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 or demonstrated risk of international spread 

• Mozambique cVDPV2 (most recent detection 17 December 2018)
• PNG cVDPV1 (most recent detection 6 November 2018)
• Indonesia cVDPV1 (most recent detection 13 February 2019)
• China (most recent detection 25 April 2019)

• 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 cross ­border 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.

Additional considerations 

• The committee urges all countries, but particularly those at high risk of polio, to maintain a high level of polio surveillance throughout the ongoing pandemic, noting that the postponement of polio immunization campaigns whether preventive or in response to outbreaks may lead to an increase in polio transmission including international spread.  There may be opportunities to strengthen polio and COVID-19 surveillance synergistically.
• Secondly, outbreak affected countries should resume immunization response campaigns as soon as feasibly possible.  The planning and implementation of the response should employ a flexible approach whereby some activities are put on hold as the transmission of COVID-19 intensifies and then resumed as the COVID-19 transmission reverses back from community transmission to the interruption of COVID-19 transmission.  Critically, campaigns should be planned and implemented in such a way that they protect front line polio workers and also the communities they serve so that COVID-19 transmission is not increased.  This includes ensuring teams have access to appropriate personal protective equipment, teams are selected so that high risk workers are not put on the front-line, and that the risks related to the pandemic are factored into the selection and planning of areas targeted by polio campaigns.
• Given the risk of international spread, countries need to ensure that they are ready to use appropriate polio vaccines, as recommended by the Strategic Advisory Group of Experts on Immunization, in response to new outbreaks.
• The committee urged countries to maximize the use of polio assets to synergistically address the COVID19 pandemic, noting that polio affected countries may be vulnerable to poorer outcomes in the pandemic due to health care system fragility and poorer health status of the population generally.  
• Lastly the pandemic should serve as a reminder to high risk countries with poor immunization coverage that infectious disease outbreaks can lead to social and economic disruption as well as straining the health care system, and countries can increase their population resilience and recovery through prioiritising  robust immunization programmes. This is relevant not only to polio, but to all other vaccine preventable diseases particularly measles.  In particular, countries whether eligible for Gavi support or not should plan to implement a second dose of IPV now being introduced to protect children from paralytic polio.
  Based on the current situation regarding WPV1 and cVDPV, and the reports provided by affected countries, the Director-General accepted the Committee’s assessment and on 3 July 2020 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 July 2020.