Serum levels of rubella-specific antibodies in Swedish women following three decades of vaccination programmes.

In Sweden, more than 30 years after the introduction of vaccination for 12-year-old girls and post-partum mothers against rubella and 22 years after the introduction of routine MMR vaccination for all children at the ages of 18 months and 12 years, we have evaluated the rubella IgG activity in antenatal sera. 95.8% (39,890/41,637) of all women had anti-rubella IgG levels ≥10IU/mL. Levels <10IU/mL were more frequent in certain subcohorts: 8.2% (153/1870) of the Swedish women born after the introduction of the programme of childhood vaccination, 7.7% (616/8025) of women born outside the Nordic countries and 10.2% (118/1155) of recent immigrants and refugees to Sweden. In order to attain the goal of protecting the unborn, we propose alternative strategies to be evaluated: routine screening for rubella immunity prior to the first pregnancy, offering individuals with uncertain immunity a booster dose, and/or routine administration of an additional dose of MMR vaccine to all young adults before they leave the educational system.