The immunity to rubella of 115 girls aged 10 to 14 years was tested in 1978. The proportion of girls found to be immune was 80%, similar to rates in the prevaccination era. Nearly half of the immunity was from documented vaccination, and the other half was presumably from infection with wild rubella virus. The vaccination failure rate was 12%. Because of declining immunity to rubella of women of child-bearing age, detecting low levels of immunity in these women is becoming increasingly important. Immunization of 12- to 15-month-old children has not been effective. Vaccinating all girls 10 to 12 years old would likely be the most effective method of preventing an increase in the incidence of congenital rubella syndrome in the next decade.
Cites: N Engl J Med. 1976 Feb 5;294(6):306-10813141
Cites: Ann Intern Med. 1975 Sep;83(3):412-71180441
Rubella vaccination status and immunity to rubella were studied in 230 "active patients" aged 8 to 22 years in a teaching family practice by means of a chart review and measurement of the rubella antibody titre in a blood sample. Of the 200 patients who submitted a blood sample 161 (80%) were found to be immune, having a rubella hemagglutination-inhibiting antibody titre of 1:16 or greater. Log linear analysis showed that immunity to rubella was independent of a history of rubella, and that 94% of the vaccinated patients versus 74% of the unvaccinated patients (a significant difference; P = 0.007) were immune. In retrospect we estimated that 80% of the study group were protected at the start of the study. After surveillance and follow-up, with vaccination of 27 of the 39 patients identified as susceptible to rubella, this estimated proportion increased to 90%. The study showed that there is nothing to be gained by asking about a history of rubella but that vaccination against this disease is increasing among children aged 5 to 9 years.