Abstract

PIP: Through a review of the work on the control of poliomyelitis carried out under the auspices of the World Health Organization (WHO) during the past 20 years, the importance of international collaboration is shown. Because of efforts in planning and coordinating, the production and control of the Sabin strains of the live oral vaccine provide safe, reliable, and potent vaccines. The cooperative efforts have included working not only with national control laboratories but with poliomyelitis vaccine producers in many countries. In the early 1970s, a Consultative Group of WHO became active. Their initial efforts included an extensive epidemiological study in 13 interested countries. Later, the group saw to studying the reliability of the marker tests used in the intratypic differentiation of poliovirus stains of different origins. Additionally, they saw to standardizing tests for the neurovirulence of vaccine lots, including analyzing and recording results, and to ensuring that adequate supplies of vaccine will be available for the next 200 years. After 15 years of continual surveillance of vaccine-associated cases by WHO epidemiologists and clinicians, the findings show the following: Type 1 live poliovirus vaccine is almost never implicated in postvaccination paralysis; type 2 strain occasionally causes of paralysis in contacts of the vaccine, and type 3 strain causes most of the few cases of postvaccine paralysis. The occurrences of the cases from type 2 and 3 strains remains an enigma. Current research of the group suggests an even more effective vaccine may become available in the future.