Evaluation of Rubella Immunization Program in Taiwan through Seroepidemiological Survey

• Main Authors: I-Jen Wang, 王怡人
• Other Authors: Chien-Jen Chen
• Format: Others
• Language: en_US
• Published: 2005
• Online Access: http://ndltd.ncl.edu.tw/handle/24372103916209577210

碩士 === 國立臺灣大學 === 預防醫學研究所 === 93 === Background: Rubella vaccination has been started since 1986 in Taiwan, the vaccination policy have changed many times. At present, children in Taiwan receive routine MMR vaccine at 15 months old and then receive a booster dose at primary school entry. Susceptible women of child-bearing age also receive MMR vaccine. Objectives: This study is carried out to examine age-specific seroprevalence of antibodies against rubella and to elucidate associated factors for seropositivity in northern Taiwan. Study design: A cross-sectional study was conducted to survey school girls aged 7∼9 years (1995∼1997 cohorts), 11∼13 years (1991∼1993 cohorts), 15∼17 years (1987∼1989 cohorts), and 19∼22 years (1982∼1985 cohorts) in Taipei County. Child bearing women aged 25∼33 years (1971∼1979 cohorts) and women older than 34 years old who came to Taipei Hospital for pre-marital, pre-labor examination, and other health examinations were also included. Rubella seropositivity was defined as serum rubella IgG antibody level ≧ 10 IU/ml by enzyme immunoassay. Participants are given an informed consent and a questionnaire detailing socioeconomic status, education level, race of mother, number of siblings, and history of rubella infection and rubella vaccination. For women older than 25 years old, ethnicity, marital status, and parity were also asked. Possible predictors of rubella seropositivity and differences in seroprevalence for each age group were calculated by multiple logistic regression. Vaccination coverage rate was also investigated. Results: Total 1144 cases were recruited. The geometric mean rubella specific IgG antibody value was found be 76.1± 61.7 IU/ml. Rubella seropositivity rates were 282/287 (98.3 %) positive in persons aged 7∼9 years, 234/235 (99.6%) in aged 11∼13 years, 179/185 (96.8%) in aged 15∼17 years, 110/119 (92.4%) in aged 19∼22 years, and 197/242 (81.4%) in aged 25∼33 years, in aged 34∼44 years 68/76 (89.5%). Seropositivity decreased with age and was the lowest in the 25∼33-year-old age group. For child bearing age women (25∼44 years old), 51 out of 53 (96.2%) seronegative women were foreigners. Age, maternal low education level, foreign mother, and no vaccination at 15 months old were correlated with seronegativity in students (p < 0.05). In addition to previous predictors, foreigners, not married, low parity, and low family income were associated with seronegativity in women. Vaccine coverage rate in students was 99.6%. Comparing with United States and Italy, rubella seropositivity rates and vaccine coverage rate are higher in Taiwan. Conclusion: The vaccine program has promoted effectively immunity. However, to eliminate rubella and chronic rubella syndrome, more effort should be made to vaccinate susceptible foreign brides and old age reproductive Taiwanese women.