Comparing the rubella seronegativity in pregnant women who received one dose of rubella vaccine at different ages in Taiwan.

INTRODUCTION

Vaccination is the best strategy to prevent rubella and congenital rubella. The aim of our study was to assess the immunity to rubella and determine rubella virus antibody titers in pregnant women who were offered a single dose of rubella vaccine at different ages of their lives.

METHODS

A total 15,067 rubella IgG antibody test results for Taiwanese pregnant women who received routine prenatal checkup at Fooyin University Hospital from 1999 to 2014 were analyzed in this study. The women were divided into five birth cohorts in order to compare their rubella seronegativities and antibody titers according to the different period of rubella vaccination policy in Taiwan.

RESULTS

The total rubella seronegativity rate was 11.2% (95% CI: 10.7-11.7%) and the mean rubella antibody titers was 51.0IU/mL (SD=54.7IU/mL). The junior school cohort has the lowest rubella seronegativity of 7.6% (95% CI: 6.9-8.2%). The seronegativities were significantly high in the preschool cohort and in the 15-month-old cohort, 14.9% (95% CI: 13.2-16.6%) and 14.8% (95% CI: 11.5-18.1%), respectively. The OR values were 2.1 (95% CI: 1.8-2.5, p<0.001) in the preschool cohort and 2.2 (95% CI: 1.6-2.8, p<0.001) in the 15-month-old cohort, respectively, against the junior school cohort. Women in the 15-month-old cohort have lowest average rubella IgG titer, 25.4IU/mL.

CONCLUSION

The total rubella seronegativity rate was 11.2% in all native pregnant women. Women who received one dose rubella vaccine at preschool and 15-month-old have highest seronegativities. The 15-month-old cohort has the lowest average rubella IgG titer. We recommend a revised catch-up immunization policy to women who received one dose rubella vaccine at a younger age.