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Evaluation of the Safety and Immunogenicity of M-M-RII (Combination Measles-mumps-rubella Vaccine)

Background: The safety and immunogenicity of M-M-RII (measles, mumps and rubella virus vaccine live, Merck & Co., Inc., West Point, PA)—the only combined measles, mumps and rubella vaccine licensed for use in the United States—were previously reported in pre- and postlicensure clinical trials conducted from 1988 to 2009. M-M-RII continues to be evaluated as a comparator in clinical trials of other vaccines. Here, we review safety and efficacy data from more recent clinical trials of M-M-RII. Methods: We performed a systematic literature review of trials using M-M-RII published from 2010 to 2019. Results: In the 15 studies that met the inclusion criteria, a total of 12,032 subjects were vaccinated: 7667 persons received a first dose only, 2137 participated in 2-dose studies (128 received 1 dose and 2009 received both) and 2063 received a single dose of M-M-RII as their second dose. Dose number was not specified for 165 participants, ≥6 years old, in 2 studies in which a single dose of M-M-RII was administered. Similar to previous reports, M-M-RII was well tolerated and immunogenic when administered alone or concomitantly with other routinely recommended vaccinations. The most common adverse events included transient injection site pain and fever. Serious adverse events were extremely rare, with only 4 probable or potential vaccine-related events reported among the 12,032 participating subjects. Conclusions: In trials published from 2010 to 2019, M-M-RII continued to be safe and immunogenic in all age groups studied. These data, along with the results of earlier trials, indicate that the performance of the vaccine has been consistent across more than 30 years of postlicensure studies.