Rates of rubella immunity among immigrant and non-immigrant pregnant women

Abstract

Objective: Elimination of congenital rubella syndrome depends not only on effective childhood immunization but also on the identification and immunization of susceptible women of childbearing age. Since many countries do not immunize against rubella, it is possible that some immigrant women may not be immune. Moreover, contemporary estimates of rubella immunity among Canadian-born mothers are lacking. Accordingly, we sought to compare the immunity status in pregnancy of a large number of immigrant and Canadian-born women in Toronto.

Methods: We examined data among 5783 consecutive pregnant women who gave birth at an inner city hospital in downtown Toronto between 2002 and 2007. Antenatal maternal rubella immunity status was recorded at the time of delivery, and assessed according to the mother's birthplace. Odds ratios (OR) for rubella immunity were adjusted for maternal age, gravidity and duration of residency in Canada.

Results: Relative to a rate of 93.2% among Canadian-born mothers, the adjusted risk of being rubella immune was lowest among women from Northern Africa and the Middle East (OR 0.54, 95% CI 0.31-0.94) and China and the South Pacific (OR 0.78, 95% CI 0.59-1.03).

Conclusion: Rates of rubella immunity are lower than desired among Canadian-born and, especially, new immigrant pregnant women. Under-immunized populations might be identified at the time of the immigration medical examination, while consideration should be given to screening for rubella immunity among all young Canadian women before puberty.