Rubella vaccination of unknowingly pregnant women: the São Paulo experience, 2001.

BACKGROUND: Rubella vaccination is contraindicated during pregnancy. During mass immunization of women of childbearing age against rubella, women unknowingly pregnant may be vaccinated. To evaluate the effects of rubella vaccination during pregnancy, the Brazilian state of São Paulo conducted a follow-up study of pregnant women vaccinated during a rubella campaign in 2001. METHODS: Women vaccinated during pregnancy were reported to a national surveillance system. In the state of São Paulo, follow-up of vaccinated women included household interviews. Serum samples from vaccinated women were tested for antirubella antibodies to classify susceptibility to rubella infection. Children born to susceptible mothers were tested for evidence of congenital rubella infection and evaluated for signs of congenital rubella syndrome. RESULTS: The São Paulo State Health Department received 6473 notifications of women vaccinated during pregnancy. Serology performed for 5580 women identified 811 (15%) that were previously susceptible. Incidence of spontaneous abortion or stillbirth among previously susceptible vaccinated women was similar to women with prior immunity. Twenty-seven (4.7%) of 580 newborns tested had evidence of congenital rubella infection; none had congenital rubella syndrome. CONCLUSIONS: Mass rubella vaccination of women of childbearing age was not associated with adverse birth outcomes or congenital rubella syndrome among children born to women vaccinated during pregnancy.

Follow-up study of unknowingly pregnant women vaccinated against rubella in Brazil, 2001-2002.

BACKGROUND: Brazil conducted mass immunization of women of childbearing age in 2001 and 2002. Surveillance was initiated for vaccination of women during pregnancy to monitor the effects of rubella vaccination on fetal outcomes. METHODS: Women vaccinated while pregnant or prior to conception were reported to the surveillance system. Susceptibility to rubella infection was determined by anti-rubella immunoglobulin (Ig) M and IgG immunoassays. Susceptible women were observed through delivery. Live-born infants were tested for anti-rubella IgM antibody; IgM-seropositive newborns were tested for viral shedding and observed for 12 months for signs of congenital rubella syndrome. Incidence of congenital rubella infection was calculated using data from 7 states. RESULTS: A total of 22 708 cases of rubella vaccination during pregnancy or prior to conception were reported nationwide, 20,536 (90%) of which were from 7 of 27 states in Brazil. Of these, 2332 women were susceptible to rubella infection at vaccination. Sixty-seven (4.1%) of 1647 newborns had rubella IgM antibody (incidence rate, 4.1 congenital infections per 100 susceptible women vaccinated during pregnancy [95% confidence interval, 3.2-5.1]). None of the infants infected with rubella vaccine virus was born with congenital rubella syndrome. CONCLUSIONS: As rubella elimination goals are adopted worldwide, evidence of rubella vaccine safety aids in planning and implementation of mass adult immunization.