Response to third rubella vaccine dose

ABSTRACTLimited data exist on the immunogenicity of a third dose of the measles, mumps, and rubella vaccine (MMR). In this study, our aim was to evaluate the long-term rubella immunogenicity afforded by two childhood MMR doses of the Norwegian vaccination program in a cohort of conscripts and to determine the effect of an additional dose of MMR vaccine, in order to inform vaccination policy. Blood samples from Norwegian conscripts (n = 495) taken both before and eight months after administration of a dose of MMR vaccine were tested using an enzyme immunoassay to measure anti-rubella IgG. Concentrations <5 IU/mL were regarded as negative, 5.0-9.9 IU/mL as equivocal, and ≥10 IU/mL as positive. Overall, the seropositivity before vaccination was 84.6%, and 99.0% of the conscripts had anti-rubella IgG concentrations ≥5 IU/mL. The seropositivity after vaccination was 94.5%, and 99.8% of the conscripts had antibody concentrations ≥5 IU/mL. The geometrical mean IgG concentrations increased from 21.4 IU/mL before ...