Immunogenicity and safety of measles-mumps-rubella vaccine at two different potency levels administered to healthy children aged 12-15 months: A phase III, randomized, non-inferiority trial

One dose of MMR-RIT formulation with lower potency (MMR-RIT-Med) induced a non-inferior immune response compared to commercial MMR II vaccine, measured by ELISA in one-year-old children. Non-inferiority was not demonstrated in terms of immune response against mumps virus measured by unenhanced PRNT, although the difference was of uncertain clinical relevance. After the second dose, immune responses were comparable among the MMR-RIT and MMR II groups.