Rubella Immunity in Pregnant Native Taiwanese and Immigrants from Asian Countries

Vaccination is considered the most effective method to prevent rubella spread and congenital rubella syndrome (CRS). The aim of the present study was to investigate the rubella immunity among native and immigrant pregnant women in Taiwan. From 2000 to 2014, a total of 16,879 pregnant women who received routine prenatal examinations were recruited in this study. The rubella IgG antibodies were assayed using a microparticle enzyme immunoassay or chemiluminescent microparticle immunoassay. Subjects were categorized by nationality and subcategorized by specific periods of time for comparison. The rubella susceptibility was 12.7% in total, 11.1% in Taiwanese and 20.3% in immigrant population from 2000 to 2014. Among the immigrant women, those from Vietnam had the highest susceptibility (22.3%) and those from Thailand had the lowest susceptibility (3.8%). The immigrant women from Vietnam and China showed a significantly higher susceptibility compared with the native Taiwanese women in which the odds ratio was 2.30 (95% confidence interval [CI]: 2.04-2.60), 1.96 (95% CI: 1.59-2.41), respectively (P < 0.001). It meant that immigrants from Vietnam and China had a higher likelihood of rubella susceptibility and related CRS sequela than native women. From 2000-2004 to 2010-2014 cohort, there was no obvious change in rubella susceptibility in native women, which varied between 10.0% and 11.9%. However, there was a decreasing trend of rubella susceptibility in the immigrant women overall, from 24.5% to 11.5% (P < 0.001). To eliminate congenital rubella in Taiwan, additional catch-up immunization strategies are needed.