Rubella seroepidemiology and catch-up immunization among pregnant women in Taiwan: comparison between women born in Taiwan and immigrants from six countries in Asia.

Rubella vaccination in Taiwan started in 1986; mass vaccination was introduced into the national immunization program in 1992. In recent years, 17-31% of all marriages in Taiwan have been between Taiwanese men and foreign women. The aim of this study was to analyze rubella seroepidemiology and the rate of catch-up immunization in women. We recruited 10,089 pregnant women, including 1,920 immigrants, who had received prenatal examinations during 1999-2006. The rates of seronegativity among global, Taiwan-born, and non-Taiwan-born pregnant women were 14.0%, 11.9%, and 23.1%, respectively. The seronegativity of rubella antibodies decreased from 28.2% for Taiwan-born women born before September 1971 to 8.0% for those born thereafter. The rates of rubella catch-up immunization among global, Taiwan-born, and non-Taiwan-born pregnant women were 28.6%, 20.5%, and 42.2%, respectively. Our results suggest that substantial numbers of older Taiwan-born women and immigrant women remain susceptible to rubella infection.