Booster effect of Rubella vaccication in college students with pre-existing low antibody titers in Japan
The object of this study was to clarify which titers are suitable for boosting immunity by rubella vaccination with the Matsuura strain. From among 435 college students, 76 students (mean age, 18.3 years old; range, 18 to 20 years old) who had rubella HI antibody titers of ≦－1:32 were enrolled in this study. After vaccination, we measured HI, ELISA-IgG and IgM titers and avidity. Among these students, who had pre-existing low antibody titers of 1:8, 1:16 and 1:32, 83%, 39% and 10% with the HI assay, and 83%, 50% and 33% with ELISA respectively, there was a significant increase in the titers. Immunity by vaccination could be boosted effectively in students with a pre-existing titer of 1:8. However, for women and high-risk people such as medical or educational workers or students, HI antibody titers ≦－ 1:16 would seem to be appropriate in Japan.