Seroprevalence of rubella infection after national immunization program in Taiwan: Vaccination status and immigration impact

Abstract

Rubella vaccination was implemented nationwide in 1992 in Taiwan. A cross-sectional survey was conducted to determine the age-specific seroprevalence of anti-rubella in female students aged 7-22 years old and women of reproductive age in Taipei County. Seropositivity of anti-rubella antibodies was defined as a serum IgG level > or =10 IU/ml tested by enzyme immunoassay. Information on possible predictors of anti-rubella seronegativity was obtained from structured questionnaire interview. Multivariate-adjusted odds ratios (ORm) with their 95% confidence interval (CI) were derived for each predictor using multiple logistic regression analysis. A total of 826 female students and 318 women were recruited. Anti-rubella seropositive rates were 98.3% (282/287), 99.6% (234/235), 96.8% (179/185), 92.4% (110/119), 81.4% (197/242), and 89.5% (68/76) for the age groups of 7-9, 11-13, 15-17, 19-22, 25-33, and 34-44 years old, respectively. Among female students, negative serology for rubella antibodies was associated significantly with the age group and foreign nationality of mother, showing ORm (95% CI) of 1.2 (1.06-1.27) for each year increase in age, and 20.9 (6.31-68.97), respectively. Among women at the reproductive age, low maternal education level 91.6 (9.12-920.74), unmarried status 21.2 (6.16-72.89), and no rubella vaccination 98.9 (11.64-840.25) were associated significantly with an increased evidence of seronegativity to rubella. The National Rubella Vaccination Program has led to herd immunity of school girls. However, in order to eradicate the Rubella syndrome, greater effort is required to vaccinate foreign brides in Taiwan.