Serologic status of women in an urban population in Brazil before and after rubella immunization campaign using routine screening data.

Background: Serologic immunity studies are necessary to evaluate immunization policies for rubella control and prevention of congenital rubella syndrome (CRS), and serologic data from regular testing for clinical follow-up can be used to complement surveillance information.
Methods: To assess immunity to rubella after an immunization campaign in 12-29-year-old girls and women, we retrospectively reviewed immunoglobulin (Ig) G tests performed from 2000 to 2003 in 9610 serum samples from pregnant subjects in Niterói, Rio de Janeiro, Brazil. Serologic tests for rubella were performed using commercial enzyme immunoassays.
Results: Rubella IgG were positive in 83.9% of serum samples collected before the campaign and in 92.5% after the campaign. The proportion of seropositive subjects was inversely related to age (P < .001). The proportion of immune girls or women aged 12-29 years, targeted by the campaign, was significantly increased after the campaign, whereas women aged ≥ 30 years, not targeted by the campaign, had no change in serologic immunity. Geometric mean titers for rubella IgG were significantly higher among pregnant girls and women after the vaccination campaign.
Conclusions: The convenience sample provided evidence of increased population immunity among the girls and women targeted by the campaign, but with a coverage of only 83% there remains a significant population at risk for rubella and thus congenital rubella syndrome.