WORLD HEALTH ORGANIZATION
ORGANISATION MONDIALE DE LA SANTE
REGIONAL OFFICE FOR THE WESTERN PACIFIC BUREAU REGIONAL DU PACIFIQUE OCCIDENTAL
REGIONAL COMMITTEE Fifty-second session Brunei Darussalam 10-14 September 2001 Provisional agenda item 11
WPR/RC52/5 25 July 2001 ORIGINAL: ENGLISH
ERADICATION OF POLIOMYELITIS IN THE REGION
The certification of the Western Pacific Region as poliomyelitis-free on 29 October 2000 was a historic event, as the Western Pacific was only the second Region in the world to have achieved poliomyelitis-free status after the Americas. However, the Region's poliomyelitis eradication programme did not end in Kyoto, for, as long as there is poliomyelitis in other parts of the world, the threat of the re-introduction of wild poliovirus into the Region remains. All countries in the Region must maintain high-quality acute flaccid paralysis (AFP) surveillance, virological surveillance and immunization coverage at high levels until global eradication has been achieved. While national immunization days (NIDs) are no longer recommended, high-risk areas with low routine coverage should consider holding subnational immunization days (SNIDs). All countries must be prepared to respond rapidly and vigorously to any importation of wild poliovirus and to the possible circulation of vaccine-derived poliovirus (VDPV). This requires high-quality surveillance to detect the virus and high immunization coverage to reduce the risk of the poliovirus spreading and to prevent VDPV. If an imported poliovirus is detected, the plans of action that were developed as part of the certification documents need to be implemented. Although transmission of wild poliovirus has been interrupted, the continued containment of wild poliovirus infectious and/or potentially infectious materials from laboratories is an important challenge that all countries will need to address. This annual report is presented for the information of the Regional Committee and for discussion at its fifty-second session.
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1. CURRENT SITUATION
On 29 October 2000, the Regional Commission for the Certification of Poliomyelitis Eradication in the Western Pacific (RCC) concluded that the transmission of indigenous wild poliovirus had been interrupted in all countries and areas of the Western Pacific Region of the World Health Organization. The Region was therefore certified as poliomyelitis-free. The sixth meeting of the RCC, held in Kyoto, Japan, from 27 to 28 October 2000, reviewed in detail the final documentation from all recently endemic and non-endemic countries, including the Pacific islands subregion. The RCC found that the documentation was of high-quality and
consistently documented the absence of wild poliovirus transmission in each country and area of the Region. Plans of action to detect and respond to importation of wild poliovirus had been developed and incorporated into national and subregional certification documents. The eleventh meeting of the Technical Advisory Group on the Expanded Programme on Immunization and Poliomyelitis Eradication in the Western Pacific Region, held in Kyoto, Japan, on 30 October 2000, made technical recommendations on maintaining poliomyelitis-free status until global eradication is achieved and on activities to contain wild poliovirus infectious or potentially infectious materials in laboratories. The Global Commission for the Certification of Poliomyelitis Eradication, during its sixth meeting held from 27 to 28 March 2001 in Washington DC, USA, endorsed the report of the RCC, concurring that the transmission of indigenous wild poliovirus had been interrupted in the Region. However, the poliomyelitis eradication programme in the Region has not ended with the certification of poliomyelitis-free status. Although much progress has been made globally, poliomyelitis is still endemic in neighbouring regions, and importation of wild poliovirus remains a possibility until global eradication has been achieved. Therefore, sustaining high immunization coverage, high-quality surveillance for cases of AFP and poliomyelitis, high-quality laboratory performance and preparedness for reliable and timely detection of and response to any importation of wild poliovirus must remain a high priority for Member States.
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Finally, substantial progress has been made in all countries and areas in initiating national laboratory inventories of wild poliovirus infectious or potentially infectious materials. However, the task of poliomyelitis eradication will not be complete until all potential sources of polioviruses are properly contained.
2.
ISSUES
1.
The certification of the poliomyelitis-free status of the WHO Western Pacific Region is a very important milestone on the road to global poliomyelitis eradication. However, countries cannot afford to be complacent. Importation of wild poliovirus from remaining poliomyelitisendemic areas may occur as long as wild poliovirus continues to circulate anywhere in the world.
2.
Consequently, the maintenance of poliomyelitis-free status requires high-quality surveillance for cases of AFP and poliomyelitis, high-quality laboratory performance, and high immunization coverage of children. Surveillance systems must be able to identify high-risk areas and populations and rapidly to detect any importation of wild poliovirus, before it can re-establish itself. High-quality surveillance must be maintained until global eradication has been achieved. Coverage with oral poliovirus vaccine (OPV) must be high in all areas to reduce the risk of spread of imported wild poliovirus.
3.
The risk of wild poliovirus importation into the Western Pacific Region is a real one, as imported polioviruses were detected in Malaysia in 1992; Yunnan, China, in 1995 and 1996; and Qinghai, China, in 1999.
4.
Despite the high overall immunization coverage with OPV in the Region, there are still some countries with low immunization coverage and in many countries there are pockets of low immunization coverage. Routine immunization of infants is essential to maintain population immunity against poliomyelitis and high levels of coverage with three doses of OPV must be maintained among all children. Special attention must be paid to immunizing hard-to-reach populations where there are incompletely immunized children.
5.
The task of poliomyelitis eradication will not be complete until all potential sources of polioviruses are properly contained. While substantial progress in implementing Phase 1 of laboratory containment of wild poliovirus infectious and/or potentially infectious materials
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based on the global and regional action plans has been made, some countries still have to complete national inventories as required for completion of Phase 1. Countries having completed Phase 1 should begin implementing the activities required for implementation of Phase 2 (see Annex). 6. While the identification of wild poliovirus infectious materials is relatively well defined, the identification of potentially infectious materials is expected to be much more difficult. Potentially infectious materials include all materials collected at a time in a region where wild poliovirus was known to have been circulating and kept under conditions known to preserve polioviruses. 7. Prior to global certification of poliomyelitis eradication, all regions will need to provide data demonstrating full implementation of Phase 2 activities of the Global Plan of Action for the Containment of Wild Polioviruses. 8. A recent outbreak of poliomyelitis reported from the Dominican Republic and Haiti was confirmed by genomic sequencing techniques to have been caused by vaccine-derived polioviruses (VDPV). Before this outbreak, the last case of poliomyelitis in the Dominican Republic had been in 1985 and in Haiti in 1989. Vaccination coverage was very low in the affected areas, as it had been before the prolonged circulation of VDPV in areas with very low OPV coverage in Egypt (estimated to have taken place from 1983 to 1993). Since no evidence for circulation of VDPV has been found in areas with high immunization coverage, the recent outbreaks reported from the Dominican Republic and Haiti underscore the need for poliomyelitis-free areas to maintain high coverage with OPV while at the same time maintaining high-quality AFP and poliovirus surveillance. 9. Maintaining poliomyelitis-free status will be a challenge for all countries and areas in the Region until global poliomyelitis eradication is assured. Certification of poliomyelitis-free status may decrease the level of commitment to the poliomyelitis eradication programme, in terms of both political and financial support.
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3.
ACTIONS PROPOSED
Following recommendations of the Technical Advisory Group and the Regional Certification Commission, the following actions by Member States are proposed for consideration by the Regional Committee. 1. Achieve and maintain high routine immunization coverage with three doses of OPV among infants. This provides the best barrier to transmission if there is any importation of wild poliovirus. SNIDs should continue to be conducted in high-risk areas (e.g. areas that border endemic countries, contain populations of special concern, or have weak routine immunization). As the Region has successfully interrupted the transmission of wild
poliovirus and has been certified as poliomyelitis-free, full-scale NIDs are no longer recommended. In order to build on the experience gained during supplementary immunization, efforts are required to improve the routine immunization programme by using detailed planning strategies, conducting effective social mobilization, giving special attention to hard-to-reach children and increasing and optimizing the number of contacts between immunization services and target children. 2. Sustain the highest possible quality of AFP and virological surveillance both to detect and respond rapidly to importation of wild poliovirus from outside the Region and to fulfil the requirements of Regional and Global Certification Commissions. All AFP cases without adequate stool samples or with poliovirus isolates must be followed up within at least 60 days of onset of paralysis. All other surveillance standards such as the non-poliomyelitis AFP rate, adequate stool collection rate, and the completeness and timeliness of reporting should be maintained at levels required for certification. 3. Put in place special action plans to ensure a rapid and efficient response if importation of wild poliovirus is detected. Such national contingency plans should include enhanced surveillance, preparation and conduct of necessary immunization response, maintenance of a response team and stocks of or access to OPV, and requirements for documentation that demonstrates that the importation did not re-establish wild poliovirus transmission. 4. In order to achieve Phase 1 of laboratory containment of wild poliovirus infectious and/or potentially infectious materials, make every effort to complete national inventories of
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laboratories which may hold wild poliovirus infectious and/or potentially infectious materials by the end of 2001. Once national laboratory lists are complete, the laboratories listed should be surveyed in order to establish whether they are holding wild poliovirus infectious and/or potentially infectious materials. A format for a national database has been developed by WHO for country use. Countries that have completed Phase 1 of laboratory containment should begin implementing the activities required for implementation of Phase 2. 5. Continue to place significant emphasis on poliomyelitis eradication activities until certification of global eradication is achieved. The Regional Certification Commission, Subregional and National Certification Committees should continue to function and the RCC should meet on an annual basis to review progress reports from all countries and areas, with particular emphasis on progress with laboratory containment of wild poliovirus infectious or potentially infectious materials, the quality of ongoing surveillance, maintenance of high immunization rates and evidence of continued political commitment.
WPR/RC52/5 page 7 ANNEX Phases of laboratory containment of wild poliovirus infectious and/or potentially infectious materials Phase I • Countries identify and develop inventories of laboratories that have wild poliovirus infectious materials and potentially infectious materials. • Laboratories institute biosafety level-2 (BSL-2/polio) procedures for safe handling of all such infectious or potentially infectious materials. Phase II • • Laboratories institute biosafety level-3 (BSL-3/polio) procedures, or Transfer wild poliovirus infectious and potentially infectious materials to WHO designated repositories, or • Render such materials non-infectious, or destroy them, under appropriate conditions.
Phase III • Laboratories institute biosafety level-4 for wild poliovirus infectious materials and potentially infectious materials. • Biosafety requirements for OPV and OPV-derived viruses will increase from BSL-2/polio to BSL-3/polio.