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.