Rubella susceptibility in sixth graders: effectiveness of current immunization practice.

Rubella hemagglutination inhibition antibody titer was determined for 702 sixth grade students from nine randomly chosen schools in a community served well medically. Rubella immunization had been given by private physicians, the health department, hospital clinics, and through a mass immunization effort in 1970. The overall susceptibility rate, as defined by a rubella hemagglutination inhibition titer of less than 1:8, was 15%. Susceptibility did not differ significantly in regard to sex, race, or source of vaccine. Of 469 children with a documented rubella immunization, 13.2% were susceptible or vaccine failures. Menarche was reported by 30% of the girls. To increase the level of protection against rubella during the childbearing years, continued emphasis on early childhood immunization combined with consideration of a booster rubella immunization for preadolescents is recommended.