Rubella-vaccinated students. Follow-up in a public school system.

In a 7 1/2-year follow-up evaluation of the duration of rubella-vaccine-induced immunity of students who received either HPV-77 DK-12 or Cendehill vaccine, both groups showed a continous decline in hemagglutination-inhibition antibody from seven weeks after vaccination but a lower decline between 4 1/2 and 7 1/2 years after vaccination. However, at 7 1/2 years only 16 students (8%) receiving the Cendehill vaccine and one student (0.5%) receiving the HPV-77 DK-12 vaccine lacked detectable antibody. Despite the persistence of antibody titers, there was evidence of subclinical rubella among both groups of vaccinated students. These results emphasize the importance of continued evaluation of the conditions of persons receiving rubella vaccine.