Comparison of immunogenicity of simultaneous and nonsimultaneous vaccination with MMR and JE vaccine among 15-month-old children.

To evaluate the immunogenicity of measles- mumps- rubella (MMR) vaccination with Japanese encephalitis (JE) vaccine nonsimultaneously and simultaneously, 145 babies, aged 15 months were enrolled into two groups. Group A received MMR and JE vaccines nonsimultaneously at an interval of 6 weeks; group B received the vaccinations simultaneously. Antibody titers of MMR and JE were detected before and 8 weeks after vaccination. A total of 118 babies (61 in group A; 57 in group B) completed the study. In group A, mean increments of logarithmic geometric mean titers (GMTs) of MMR and JE were 4.51, 5.93, 4.07 and 1.99; seroresponse rates were 100% (61/61), 77.05% (47/61), 96.72% (59/61) and 59.02% (36/61) respectively. In group B, mean increments of logarithmic GMTs of MMR and JE were 4.35, 5.37, 4.44 and 1.93; seroresponse rates were 98.25% (56/57), 77.19% (44/57), 98.25% (56/57) and 57.89% (33/57) respectively. There were no significant differences between these two groups. These results suggest that simultaneous and nonsimultaneous vaccination with MMR and JE vaccines were similar in immunogenicity.