The purpose of this study was to see how maternally generated antibodies affected the immunogenicity of Sabin IPV. At 2, 3, and 4 months of age, 600 babies were randomly assigned to one of five different vaccines: the high-dose (group A), medium-dose (group B), or low-dose (group C) of experimental Sabin IPV, the control Salk IPV (group D), or the control Sabin IPV (group E). For varying maternal antibody levels, the GMTs, GMIs, and seroconversion rates of poliovirus type-specific neutralizing antibodies were examined. Linear regressions were also used to model the associations between maternal antibody levels and post-vaccination antibody responses. Post-vaccination GMTs were considerably lower in babies with strong maternal antibody titers for poliovirus type 1 or 2, primarily in groups B, C, D, and E. In all five groups, GMIs and seroconversion rates fell considerably as maternal antibody levels increased. Maternal antibody levels were shown to be inversely related to post-vaccination antibody titers and fold increases in groups A, B, and C. As the potency of the experimental Sabin IPVs decreased, the linear regression coefficients rose in groups A, B, and C.

Finally, large levels of maternal poliovirus antibodies may dampen immunological responses to Sabin IPVs. Changing the potency of the experimental Sabin IPVs might change the relationships between maternal antibody levels and baby serologic responses.