Immunogenicity of oral poliovirus vaccine administered in mass campaigns versus routine immunization programmes.

Reported are the results of a study to investigate the immunogenicity of oral poliovirus vaccine (OPV) when administered in mass campaigns compared with that following routine immunization programmes. For this purpose, paired sera were collected from a cohort of children before and after a mass vaccination with OPV in Morocco in 1987. Serum samples and information on vaccination status and other confounding factors that could influence antibody responses to OPV were collected.

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.