Outbreak of rubella after mass vaccination of children and adult women: challenges for rubella elimination strategies.

Objective: To describe rubella outbreaks and control strategies in the Brazilian state of Rio Grande do Sul before rubella elimination.

Methods: We analyzed rubella and congenital rubella syndrome surveillance data for the state of Rio Grande do Sul and calculated age- and gender-specific incidence of confirmed rubella cases in 2007. We obtained data on measles-rubella doses administered during the outbreak from the state immunization program and reviewed the timing of suspect case notification and implementation of control measures.

Results: Of 2,842 confirmed rubella cases reported to the state health department in 2007, 2,145 (75.5%) were in males (39.5 cases per 100,000 population) and 697 (24.5%) were in females (12.3 per 100,000 population). Incidence among 15- to 39-year-olds was 1.8 to 5.5 times higher in males than in females. Rubella genotype 2B was detected in nasopharyngeal specimens from 13 patients from multiple chains of transmission. Eight children were born with congenital rubella syndrome (5.9 cases per 100 000 births in 2008). Delayed notification of initial cases hampered early control efforts, resulting in outbreak spread throughout the state. Rubella transmission was interrupted after mass vaccination of adult men and women as part of a national vaccination campaign.

Conclusions: Routine vaccination strategies and mass vaccination of adolescents and adults for accelerated rubella control and elimination should target men and women.