Immunological response of Moroccan children and newborns to oral poliovirus vaccine prepared on Vero cells.

Immunogenicity of the oral poliovirus vaccine prepared on Vero cells (Vero OPV) has been assessed in a two-stage study conducted in Rabat, Morocco. During the first stage, the vaccine produced seroconversion in most of the 200 children vaccinated in a three dose primary immunization, and in most of the 56 children boostered. During the second stage, four doses were given at 0, 6, 10 and 14 weeks of age to 55 newborns. At the same time, 50 control newborns were given reference OPV prepared on primary monkey kidney cells (PMK OPV). No difference could be shown between the two vaccines in terms of immunogenicity. Therefore, permitting a more standardized production, continuous cell lines should be used for the production of OPV.