Given the above and considering: (1) future clinical study with the MMR vaccine produced entirely in Bio-Manguinhos/Fiocruz from technology transfer from GlaxoSmithKline (GSK), (2) the importance to the National Immunization Program (NIP) to provide the population a MMR vaccine to ensure high protection against mumps, similar to what occurs with measles and rubella components, it was considered essential to conduct a preliminary immunogenicity assessment of the MMR vaccine produced by BioManguinhos.