1 table, 1 figure omitted
IN 1988, the World Health Assembly resolved to eradicate poliomyelitis by 2000; this goal was reaffirmed in 1989 by the World Health Organization (WHO) Regional Committee for Europe. Although most of the 51 member states of the European Region of WHO (EUR) (including Israel and the Central Asian Republics) have reported zero polio cases since at least the early 1980s, endemic transmission or outbreaks of polio continued to be reported through 1996 in some countries. This report updates progress of the EUR polio eradication initiative through September 1997,1,2 including progress in polio vaccination activities, interruption of wild poliovirus transmission, and the establishment of sensitive surveillance systems in the region.
In 1995 and 1996, a total of 41 EUR countries routinely used oral poliovirus vaccine (OPV) for infant vaccination, six used inactivated poliovirus vaccine (IPV), and four used sequential IPV-OPV schedules. In 1996, the provisional regional average for coverage with a primary series of polio vaccination by age 1 year was 92% (range: 77%-100%, with 26 countries reporting), compared with 83% in 1993 (range: 45%-100%, with 46 countries reporting); coverage levels in many of the Newly Independent States of the Former Soviet Union reached their lowest points during the economic transitions of the early 1990s.
The third year of an international mass vaccination activity—Operation MECACAR (Eastern Mediterranean, Caucasus, Central Asian Republics)—was completed in May 1997. Operation MECACAR consisted of coordinated National Immunization Days (NIDs)* in the bordering countries of the WHO Eastern Mediterranean and European regions with continuing endemic polio.1 During each of these NIDs, 58-60 million children (95% of targeted children) received two supplementary doses of OPV. Nine countries of EUR (Armenia, Azerbaijan, Georgia, Kazakhstan, Kyrgyzstan, Tajikistan, Turkey, Turkmenistan, and Uzbekistan) participated in all 3 years of Operation MECACAR. The Russian Federation joined MECACAR in 1996 and 1997. Bulgaria also conducted NIDs in synchrony with Operation MECACAR in 1995. In addition to Operation MECACAR, five other EUR countries at high risk for polio conducted NIDs or sub-NIDs in 1996 (Albania, Republic of Moldova, Romania, Ukraine, and the Federal Republic of Yugoslavia).
Because of a polio outbreak following a wild poliovirus importation into the Balkan peninsula during 1996, extra emergency mass vaccination rounds were conducted during 1996 and/or 1997 in Albania, Bosnia, Croatia (Eastern Slavonia section), the Federal Republic of Yugoslavia, Herzegovina, and The Former Yugoslav Republic of Macedonia. Two rounds of targeted "catch-up" vaccination also were conducted in Greece in 1996 as a result of the epidemic.
By 1996, all 16 EUR member states that had reported epidemic or endemic polio since 1991 had established surveillance for acute flaccid paralysis (AFP), the surveillance strategy recommended by WHO for polio eradication. Fifteen EUR member states without endemic disease also had instituted such systems. A total of 33 member states will be conducting AFP surveillance by the end of 1997. During January 1996-September 30, 1997, six countries (Belarus, Israel, Kazakhstan, Romania, the Russian Federation, and Ukraine) achieved the minimum AFP reporting rate indicative of a sensitive surveillance system (at least one nonpolio AFP case per 100,000 children aged <15 years annually). The regional nonpolio AFP rate increased from 0.3 in 1995 to 0.7 (range: 0-2.2) in 1996; based on cases reported through September 1997, the annualized rate for 1997 was 1.1. The rate of collection of two adequate stool samples† from persons with reported AFP cases increased from 47% in 1995 to 68% in 1996; through September 1997, 78% of reported AFP cases had two adequate specimens. During 1996 and 1997, Armenia, Belarus, Kazakhstan, Kyrgyzstan, Romania, and Turkmenistan consistently achieved the WHO-recommended target of two adequate stool specimens collected from at least 80% of AFP cases.
The EUR polio laboratory network consists of 41 laboratories (34 national laboratories; two subregional reference laboratories; and five regional reference laboratories).3 Of the 33 EUR network laboratories that underwent proficiency testing during 1996, a total of 25 rated a passing score (at least 80%) compared with five of the 15 laboratories tested in 1995.
From 1991 through 1995, the number of confirmed cases of polio reported in EUR ranged from 177 to 221; 193 cases were reported in 1996. Of the 50 EUR member states that reported 1996 data to WHO, 42 reported zero cases, compared with 38 countries in 1994 before Operation MECACAR. Of the nine countries with endemic or recently endemic disease that participated in Operation MECACAR during 1995-1997, two (Turkey and Turkmenistan) reported 21 cases in 1996. During 1991-1994, these nine countries had reported 78-221 polio cases each year. Of the 50 EUR member states that have reported 1997 data to WHO, only Tajikistan has reported one confirmed polio case. In 1996, most reported polio cases in EUR occurred during an outbreak that followed an importation of wild poliovirus type 1 into the Balkan peninsula. As part of that outbreak, 138 cases were reported from Albania4; additional cases occurred in young, undervaccinated population subgroups: among Roma (gypsies) in Greece (five cases) and among ethnic Albanians in the Kosova and Metohija district of the Federal Republic of Yugoslavia (24 cases). The outbreak in Albania primarily affected persons aged 10-34 years because of historical problems with the transport, storage, and administration of vaccines. The outbreak ended following mass vaccination of the entire population through age 50 years with two doses of OPV, reaching >85% of the target group. Similarly, in the Federal Republic of Yugoslavia the outbreak was terminated by previously planned sub-NIDs. Wild poliovirus type 1 also was isolated in Turkmenistan in July 1996. The remaining cases reported in 1996 (in the Republic of Moldova, Russian Federation, Turkey, and Ukraine) and 1997 (in Tajikistan) were clinically confirmed. Wild poliovirus types 1 and 3 were last isolated in Turkey in 1994 and 1995, respectively.
Based on epidemiologic investigations and the genomic characterization of wild poliovirus isolates, approximately 52% of the 1335 polio cases reported in EUR member states during January 1991-September 1997 were associated with indigenous transmission of wild poliovirus of origin from outside the involved country, and sometimes apparently from outside the EUR, primarily affecting susceptible populations or subgroups. During 1991-1995, most outbreaks were associated with wild poliovirus originating from the Indian subcontinent.5,6
Communicable Disease and Immunization Unit, European Regional Office, Copenhagen, Denmark. Global Program for Vaccines and Immunization, World Health Organization, Geneva, Switzerland. Respiratory and Enteric Viruses Br, Div of Viral and Rickettsial Diseases, National Center for Infectious Diseases; Polio Eradication Activity, National Immunization Program, CDC
Improvements in routine vaccination coverage and in surveillance in the EUR member states and the successes of Operation MECACAR have resulted in substantial progress toward regional elimination of wild poliovirus transmission. In addition to most of western and central Europe, which have not reported polio in the 1990s, polio transmission has been interrupted in virtually all of those countries in which polio was endemic. However, the quality of surveillance in many areas of the region must continue to improve to ensure that endemic transmission has been interrupted and that any transmission secondary to imported poliovirus is promptly detected.
Tajikistan, Turkmenistan, and Uzbekistan remain at risk for polio because of recent cases and suspected ongoing poliovirus transmission in Afghanistan; however, transmission might not be detected because of weak surveillance and/or laboratory deficiencies. In addition, some areas of Turkey—particularly those adjacent to Iran and Iraq—remain at high risk for wild poliovirus transmission.7
Supplemental vaccination activities (i.e., NIDs, sub-NIDs, and "mopping-up" [intensive house-to-house supplemental vaccination in high-risk areas]) will continue to be organized through 2000 under Operation MECACAR Plus to interrupt any remaining chains of poliovirus transmission. Mopping-up activities will be conducted in nearly all MECACAR countries during October-November 1997, with particular emphasis on the high-risk areas that border countries of the Eastern Mediterranean Region with endemic disease.
Since the late 1980s, large polio outbreaks have occurred nearly every year in EUR among undervaccinated religious or ethnic population subgroups or in countries where vaccination coverage decreased for economic reasons.4-5,8 As progress has been made in the interruption of endemic transmission, the relative importance of indigenous transmission of virus introduced from outside the region has increased. Therefore, specific efforts are needed to identify and improve the vaccination status of hard-to-reach population subgroups in member states (e.g., ethnic minorities, migrants, and displaced persons).
EUR priorities for the eradication of polio by 2000 include (1) further strengthening AFP surveillance systems throughout the region (including accreditation of polio network laboratories by mid-1998); (2) ensuring that high-quality NIDs or sub-NIDs are conducted through Operation MECACAR Plus in selected countries with persistent high risk for wild poliovirus circulation resulting from low vaccination coverage, weak surveillance, and/or administrative problems; (3) implementing coordinated intensive supplemental vaccination activities among key border area populations; (4) maintaining and strengthening the political commitment of governments for polio eradication and certification; (5) consolidating the support of donor governments and partner agencies to ensure sufficient financial and human resources are available; and (6) progressing in the formal process of certification. External technical and financial support provided to achieve progress in the polio eradication initiative in EUR has been provided by an international coalition consisting of WHO; United Nations Children's Fund (UNICEF); and other partner agencies including Rotary International, US Agency for International Development, CDC, and the governments of Canada, Denmark, France, Germany, Italy, Japan, Luxembourg, the Netherlands, Norway, Switzerland, and the United Kingdom and the European Commission Humanitarian Office.
Progress Toward Poliomyelitis Eradication—Europe and Central Asian Republics, 1991-September 1997. JAMA. 1998;279(2):103-104. doi:10.1001/jama.279.2.103-JWR0114-2-1