Certification of the eradication of poliomyelitis

WHO News and activities Certification of the eradication of poliomyelitisa In passing Resolution WHA41.28 in 1988, the Forty- first World Health Assembly committed WHO to the global eradication of poliomyelitis by the year 2000. Since then considerable progress has been made towards achieving this target, and in addition to the Americas, the following poliomyelitis-free ar- eas are emerging: Western and Central Europe, Southern and Eastern Africa, the Maghreb countries of North Africa, the Middle East, the Arabian Penin- sula, and the Pacific basin. Evaluation of poliomyeli- tis eradication activities and certification of global eradication will be the final stage. The first meeting of the Global Commission for the Certification of the Eradication of Poliomyelitis was held in Geneva on 16-17 February 1995. Below are summarized the most important recommendations made by the participants. Basis for global poliomyelitis eradication The following criteria provide a basis for assessing possible eradication of poliomyelitis: absence of virologically confirmed cases for a period of 3 years in the presence of adequate surveillance; absence of detectable wild poliovirus in the stools of healthy children and, where indicated, from wastewater; evaluation by a national certification committee, convened for that purpose, eventually reporting to the regional commission; and establishment of appropriate measures to deal with importations of poliovirus. In each country a national commission should convene to review and oversee pre-certification ac- tivities, documenting four strategies as the basis for country reports: surveillance for cases of acute flaccid paralysis (AFP); a Based on: Report of the First Meeting of the Global Commission for the Certification of the Eradication of Poliomyelitis. Unpublished document WHO/EPI/GEN95.6, 1995. Reprint No. 5680 - surveillance of wild polioviruses; - routine immunization activities; and - supplemental immunization campaigns designed for poliomyelitis eradication. Principles for certifying global poliomyelitis eradication Below are listed the basic principles on which global poliomyelitis eradication will be certified. * Certification will be carried out on a regional or subregional basis by commissions convened for this purpose. * The Global Commission for the Certification of Polio Eradication will provide guidelines that will form the basis for the work of the regional commis- sions to ensure uniformity in the criteria used to assess eradication. The Global Commission will es- tablish a timetable within which the regional com- missions may be expected to operate. Although all regions do not have to be evaluated at the same time, countries already certified as having eradicated wild poliovirus must continue to immunize, maintain high levels of AFP and virus surveillance, and retain the capacity to deal with importations should they occur. * Certification of poliomyelitis eradication will be based on assessment of documented evidence, focus- ing particularly on the effective surveillance both for cases of AFP and for wild polioviruses. * Certification of global poliomyelitis eradication will only be made when all regions have been certi- fied as having achieved wild poliovirus eradication. In countries that have been free of poliomyelitis for years, innovative methods of assessing that wild poliovirus no longer exists within their boundaries may be required. * In any area, final certification of eradication will not be considered until 3 years have elapsed since the last detected and culture-confirmed occurrence of a wild poliovirus. Until global eradication of po- liomyelitis is confirmed, AFP surveillance and its documentation must continue. Eradication criteria Surveillance for cases of AFP. The criteria shown below must be met before certification can be considered. Bulletin of the World Health Organization, 1996, 74 (1): 109-111 © World Health Organization 1996 109 WHO News and activities • Documentation of the timely receipt of >80% ofexpected routine surveillance reports, including zeroreporting where no AFP cases were seen. Adequateinvestigation and analysis of the reasons for non­reporting, with appropriate documentation, willidentify whether missing reports consistently relateto certain geographical areas, to delays in receipt ofreports, or other factors.• In each country and area within countries the inci­dence of AFP per 100000 children aged under 15years gives an indication of the adequacy of surveil­lance for this condition. In small populations a con­glomerate of adjacent areas should be assessedtogether. An AFP incidence >1 per 100000 childrenaged 15 years is a clear indicator of the probableeffectiveness of surveillance.• At least 80% of reported AFP cases should beinvestigated within 48 hours.• Ali suspected poliomyelitis cases should be inves­tigated in detail, including clinical, epidemiological,and virological examinations and a 60-day follow-upexamination for residual paralysis. When ail investi­gations have been completed a final case classifica­tion should be made on the basis of the results by acommittee of experts convened for this purpose. Surveillance for wild polioviruses. The criteria shown below were established for surveillance of wild polioviruses. • Assessments should demonstrate that high levelsof competence have been achieved by the labor­atories certified as part of the global/regional net­works, including successful results in proficiencytesting. Virus isolation tests, including those thatare negative, will be accepted only from networklaboratories. Isolation of viruses by laboratories out­side the network must be confirmed by a networklaboratory.• Specimen collection, transport and testing proce­dures must be validated through the use of perform­ance indicators and proficiency testing.• Over the preceding 3 years no wild poliovirus willhave been isolated from two stool samples of AFPcases. Also, two stool samples will have been col­lected within 14 days of onset of the illness from atleast 80% of AFP cases detected and investigated.• Over the preceding 3 years no wild poliovirus willhave been isolated from stool specimens collected 110 from contacts of cases. Ideally, five under-5-year-old contacts of each AFP case will have been tested. • The highest priority for testing wild poliovirus inthe environment will be the collection and testing offaecal samples from healthy children living nearcases of AFP under investigation. WHO Bulletin OMS. Vol 741996