Safety and Immunogenicity of M-M-RII (Combination Measles–Mumps–Rubella Vaccine) in Clinical Trials of Healthy Children Conducted Between 1988 and 2009

BACKGROUND: M-M-RII, a combination measles, mumps and rubella vaccine, was licensed in the United States in 1978 based on data from several clinical trials that demonstrated that the safety and immunogenicity of the vaccine were comparable to the component monovalent vaccines and to the previous trivalent combination vaccine. METHODS: Safety and immunogenicity data from 23 postlicensure clinical trials conducted with M-M-RII between 1988 and 2009 were summarized. A total of 12,901 children who received only a first dose, 920 children who received a first and second dose and 400 children who received only a second dose were evaluated. RESULTS: The vaccine was generally well tolerated among children who received a first and/or second dose of M-M-RII. During the 28-42-day follow-up after dose 1 and dose 2, the median rate of temperatures ≥102°F (oral equivalent) was 24.8% and 13.0% and the median rate of measles/rubella-like rash was 3.2% and 0.5%, respectively. The median rate of injection-site reactions during the first 5 days postdose 1 and postdose 2 was 17.3% and 42.7%, respectively. The seroconversion rates (enzyme-linked immunosorbent assay) after dose 1 were remarkably consistent from study to study between 1988 and 2009 (92.8%-100% for measles, 97.7%-100% for mumps and 92.8%-100% for rubella). A trend test showed that there was no change in the immunogenicity of the vaccine over the 21-year period. CONCLUSIONS: The results of this analysis demonstrate that M-M-RII is well tolerated and immunogenic. The vaccine performed consistently over 21 years of evaluation in clinical trials.