Domestic measles, mumps, and rubella (MMR) vaccinations were withdrawn from the market in Japan in 1993 due to an unexpectedly high incidence of aseptic meningitis. It was thought that an efficient MMR vaccination with decreased reactogenicity would be introduced. A novel MMR vaccination (JVC-001) was created by combining the mumps RIT4385 strain with the Japanese measles AIK-C strain and the rubella Takahashi strain (MR) vaccine. In an open-label, randomized, phase I/II clinical research, 100 healthy Japanese children were randomly assigned to one of two groups: JVC-001 or MR with monovalent mumps vaccination. On Day 0 and Day 42–56, immunogenicity was evaluated using a neutralization test (NT) for measles, a hemagglutination inhibition (HI) test for rubella, and an NT and enzyme-linked immunosorbent assay (ELISA) for mumps strains with various genotypes. Adverse experiences (AEs) were documented, both solicited and uninvited. Measles and rubella seroconversion rates were both 100%. JVC-001 produced greater immunogenicity against mumps virus genotype G, with a 77.1 percent seroconversion rate compared to 65.3 percent in the control group. The geometric mean titer (GMT) in the JVC-001 group was 12.5 and 7.1 in the control group. JVC-001 was also immunogenic against additional genotypes.

There was no discernible difference in the occurrence of AEs between the JVC-001 and control groups. When compared to the presently marketed vaccinations in Japan, JVC-001 is safe and generates effective immunogenicity against measles, mumps, and rubella.