Progress Toward Poliomyelitis Eradication -- Eastern Mediterranean Region, 1998-October 1999
In 1988, the Regional Committee for the Eastern Mediterranean Region* (EMR) of the World Health Organization (WHO) adopted a resolution to eliminate poliomyelitis from the region by 2000. This report summarizes progress toward this goal in EMR countries through October 1999; all EMR countries, including war-torn and other underdeveloped areas of the region, are conducting essential polio eradication strategies, and eradication activities to rapidly stop poliovirus transmission are under way in countries where polio is endemic.
Routine Vaccination Coverage
In 1998, regional routine coverage with at least three doses of oral poliovirus vaccine (OPV3) by age 1 year was 82% (range: 24%-100%). All member countries reported routine coverage data, and OPV3 coverage was greater than or equal to 90% in 16 countries. However, reported OPV3 coverage was 86% in Iraq, 79% in Pakistan, 72% in Sudan, 68% in Yemen, 62% in Djibouti, 35% in Afghanistan, and 24% in Somalia. Countries reporting less than 90% coverage represent more than half of the regional population. Compared with the reported coverage rates, most of which are determined by using target population estimates, population-based surveys in Afghanistan, Iraq, and Pakistan have found lower coverage rates.
Supplementary Vaccination Activities
During 1998 and 1999, National Immunization Days (NIDs)** were conducted in 19 countries. In 1998, Somalia and Sudan conducted the first countrywide campaigns that covered the war-affected southern parts of each country (1). Kuwait did not conduct NIDs in 1998 but will conduct one round in November 1999. Iran and Tunisia conducted targeted Subnational Immunization Days (SNIDs)*** in provinces at risk for poliovirus importation and/or with suboptimal vaccination coverage. NIDs have not been necessary in Cyprus because routine coverage is high. Poliovirus circulation has persisted or is suspected in seven EMR countries (Afghanistan, Egypt, Iraq, Pakistan, Somalia, Sudan, and Yemen) because of low routine OPV3 coverage and/or pockets of unvaccinated children not reached during NIDs. Accelerated vaccination activities, which include improving the quality of all campaigns, adding rounds of NIDs or SNIDs, and intensifying house-to-house vaccination in high-risk areas, have been initiated in these countries (Figure 1). For example, in early 1999, greater than 11 million children were vaccinated during two rounds of a house-to-house vaccination campaign in three provinces of Pakistan, and Afghanistan and Iraq are conducting two pairs of NIDs in 1999.
Within EMR, campaigns are coordinated among groups of contiguous countries, including Afghanistan, Iran, and Pakistan; Iran, Iraq, and Syria (and Turkey) (2); between member states of the Gulf Cooperation Council****; and between Maghrebian Union countries, including Libya, Morocco, and Tunisia. NIDs in several countries have been coordinated with countries in the European region ("Operation MECACAR") and the African region in the Horn of Africa. NIDs in Pakistan have been synchronized with campaigns in southern Asia (3,4).
By mid-1998, all member countries (except Djibouti) had established acute flaccid paralysis (AFP) surveillance. Fifteen countries (Bahrain, Cyprus, Egypt, Iran, Iraq, Jordan, Kuwait, Lebanon, Libya, Oman, Palestine, Qatar, Saudi Arabia, Syria, and Tunisia) had achieved or exceeded the WHO-established minimum AFP reporting rate indicative of a sensitive surveillance system (one or more nonpolio AFP case per 100,000 children aged less than 15 years) during 1998 (Table 1). Among the eight remaining countries, the annualized nonpolio AFP reporting rates during 1999 have exceeded one case per 100,000 in Afghanistan, Pakistan, United Arab Emirates, and Yemen. The regional average reporting rates for nonpolio AFP in 1998 and 1999 were 0.88 and 1.21, respectively. During 1998 and 1999, two adequate***** stool samples were collected from 64% and 68%, respectively, of the persons with reported AFP in EMR. During 1998 and 1999, seven countries (Cyprus, Kuwait, Oman, Palestine, Saudi Arabia, Syria, and Tunisia) achieved the WHO-recommended target of two adequate stool specimens collected from at least 80% of persons with AFP. An additional five countries (Bahrain, Egypt, Iran, Iraq, and Jordan) collected stool specimens from 71% to 79% of persons with AFP reported during the same period, and six countries (Lebanon, Morocco, Qatar, Somalia, Sudan, and United Arab Emirates) collected adequate specimens from less than 50% of persons with AFP. Despite high national AFP surveillance performance indicators during 1997 and 1998 in Egypt and Iraq, circulation of wild poliovirus type 3 in Egypt and type 1 in Iraq continued undetected for greater than 2 years.
EMR Laboratory Network
The EMR laboratory network comprises 12 laboratories (eight national and four regional reference laboratories). During 1998, all network laboratories except those in Iraq and Sudan were accredited by WHO. On the basis of their improved performance, the laboratories in Iraq and Sudan received provisional accreditation in 1999. As of October 1999, 3445 stool specimens from 1800 (99%) of 1824 persons with AFP reported from 22 EMR countries underwent laboratory investigation in a WHO network laboratory. Laboratory results were reported on time (within 28 days of receipt of specimen) for 80% of stool specimens. The regional average nonpolio enterovirus isolation rate (an indicator of the adequacy of laboratory technique and specimen handling) was 9%; 93% of the specimens were received in the laboratory in good condition. Genetic sequence analyses are performed routinely on all wild poliovirus isolates in the region. The information has provided evidence of progress toward eradication through identifying virus reservoirs, establishing virus transmission links and cross-border importations, and detecting laboratory contamination (5).
Incidence of Polio
From 1988 through October 1999, the number of confirmed polio cases reported in the EMR decreased 81%, from 2342 to 446. Of 23 EMR countries, 15 reported zero cases during 1999. Since 1996, five countries (Afghanistan, Egypt, Iraq, Pakistan, and Sudan) have reported cases with indigenous strains of wild poliovirus. The last virologically confirmed case of polio in Egypt had onset in March 1999. Wild poliovirus has not been isolated in Somalia through a functioning surveillance system in the north or from AFP cases reported in Yemen during 1998 and 1999. During 1998 and 1999, Pakistan continued to report the largest number of cases and contributed nearly 60% of the total number of cases in the region. Wild poliovirus type 2 has not been isolated in EMR since 1997 (Figure 2).
Countries with high-quality AFP surveillance that have been polio-free for several years have begun to prepare documentation for review by the Regional Commission for Certification of Polio Eradication. In late 1999, the commission will review documentation from five EMR countries and from an additional 10 countries before the end of 2000.
Reported by: Regional Office for the Eastern Mediterranean Region, Alexandria, Egypt. Vaccine and Biologicals Dept, World Health Organization, Geneva, Switzerland. Respiratory and Enteric Viruses Br, Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases; Vaccine Preventable Disease Eradication Div, National Immunization Program, CDC.
Member countries of EMR have made remarkable progress toward polio eradication since 1988. Most EMR countries are now polio-free in the presence of high-quality AFP surveillance, and the intensity of virus transmission is decreasing rapidly in countries where polio is endemic. Supplementary vaccination campaigns and AFP surveillance have been implemented in all EMR countries, including areas in conflict, in Afghanistan, Somalia, and Sudan (1,6). Progress made in those countries faced with armed conflict, political instability or economic sanctions, poor health infrastructure, and population displacement is encouraging.
EMR countries have gained sufficient experience in the most challenging circumstances to implement effectively accelerated polio eradication activities. Accelerated activities to stop virus transmission by the end of 2000 have begun in seven countries of EMR where polio is known or suspected to be endemic. Efforts to improve the quality of vaccination campaigns include advanced preparations, better local level planning, extensive supervision, house-to-house vaccination, community mobilization, and heightened political commitment. Additional NIDs, SNIDs, or "mopping-up" will be conducted during the next 18-24 months in these countries. AFP surveillance is being strengthened through regular active surveillance in major health facilities, designation and training of responsible staff, and strong central coordination, supervision, monitoring, and evaluation.
Rapid reduction in virus transmission during summer 1999 in Egypt and parts of Pakistan where additional intensified campaigns were conducted in spring 1999 has provided strong preliminary evidence of the impact of these accelerated vaccination activities. During 1999, training of designated staff followed by implementation of regular active surveillance at lower administrative levels in selected districts and governorates of Pakistan and Yemen, have led to rapid improvements in surveillance performance in these countries. Undetected circulation of wild poliovirus type 3 in Egypt for greater than 2 years highlight the importance of high quality surveillance at subnational levels. Undetected circulation of wild poliovirus type 1 in Iraq indicates the need for ensuring that all components of an AFP surveillance system, particularly stool specimen collection, storage, transport, and testing in a WHO-accredited laboratory, are functioning adequately. A greater emphasis has been placed on improving surveillance performance at subnational levels in these two countries.
Successfully implementing accelerated activities will require strong and more effective political commitment from the highest level within the countries******. Further consolidation is needed among WHO, United Nations Children's Fund, other United Nations agencies, and nongovernmental organizations (NGOs), particularly in areas of the region without any recognized governments. The intensified campaigns, additional NIDs, and rapid development of surveillance require substantial additional human and financial resources that must be provided jointly by the concerned governments and partner agencies and by the global coalition of partners and local NGOs in areas without a government.
* Member countries are Djibouti, Egypt, Libya, Morocco, Somalia, Sudan, and Tunisia in northern and eastern Africa; Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, United Arab Emirates, and Yemen in the Arab Gulf states; Iraq, Jordan, Lebanon, Syria, and the Palestinian National Authority in the Middle East; Afghanistan, Iran, and Pakistan in Asia; and Cyprus.
** Mass campaigns over a short period (days to weeks) in which two doses of OPV are administered to all children in the target age group (usually aged less than 5 years) regardless of previous vaccination history, with an interval of 4-6 weeks between doses.
*** Focal mass campaigns in high-risk areas over a short period (days to weeks) in which two doses of OPV are administered to all children in the target age group, regardless of previous vaccination history, with an interval of 4-6 weeks between doses.
**** Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, and United Arab Emirates.
***** Two stool specimens collected at least 24 hours apart within 14 days of onset of paralysis.
****** EMR polio eradication efforts are supported by its member countries, WHO, United Nations Children's Fund (UNICEF), Rotary International, CDC, the United Kingdom, Japan, Canada, Denmark, Norway, and Italy.
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TABLE 1. Number of reported cases of acute flaccid paralysis (AFP) and confirmed poliomyelitis* and key surveillance indicators, by country -- Eastern Mediterranean Region, 1998-October 1999
* A confirmed case of polio is defined as AFP and at least one of the following: 1) laboratory-confirmed wild poliovirus infection, 2) inadequate stool specimens and residual paralysis at 60 days, 3) death, or 4) no follow-up investigation at 60 days.
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