On the role of the World Health Organization in the development of Sabin vaccines.

The World Health Organization has played a major part in the development, surveillance and distribution of attenuated poliovirus vaccines. At a time when most of the United States' efforts concerned the introduction of Salk-type vaccines, WHO initiated studies that set standards and permitted the large scale trials of Sabin and other attenuated vaccines. Independent expert review validated studies in countries such as the U.S.S.R. which helped lead to the adoption of Sabin vaccines for worldwide usage. Surveillance by WHO Collaborative Centres established the safety of Sabin vaccines and identified issues of reversion primarily concerning type 3 viruses, initiating studies which have elucidated the molecular mechanism of reversion. Efforts by the Biological Unit of the World Health Organization have ensured worldwide acceptable standards to control the safety and manufacture of vaccines. Revision of neurovirulence test methods has ensured adequate safety testing of vaccine lots, reduced the costs of such studies and the numbers of primates needed, important ethical and conservation issues. Finally, the World Health Organization has played a major part in the worldwide supply of vaccines at affordable prices and has been the repository of, and had the exclusive license, to Sabin vaccines since 1972.