ABSTRACT
The aim of this study was to determine measles antibody titer in children who received two doses of vaccine and were reimmunized at 7 years of age. The school children were randomly choosen from various areas of Tehran who had received two doses of measles vaccine at 9 and 15 months of age and reimmunized at 7 years of age. Measles antibody was measured in children aged 7 years and 4-6 weeks after reimmunization by Enzyme-linked immunosorbent assay [ELISA]. A total of 339 children were evaluated. Antibody titers in 132 [38.9%] children were more than 10 IU/ml [mean 68.3 IU/ml] and 207 [61.1%] less than 10 IU/ml. Antibody titers in 32 of 42 children who had been reimmunized were less than 10 IU/ml. In two [6.3%] of 32 children antibody titers did not rise after reimmunization and the mean antibody titer in remainder [30] of the children was 71.3 IU/ml. Antibody titers in 10 [23.8%] of 42 children before and after reimmunization were 58 and 168.5 IU/ml respectively. After reimmunization, the mean antibody titer in children with high titer before reimmunization was higher than those with low antibody titer. This study indicates that children with two dose measles immunization before and after the first year of age are still immunologically resistant against measles at 7 years of age. Immunization is the most efficacious and cost effective intervention available to improve the health and wellbeing of children and prevention of the infectious disease