immunity against measles among vaccinated school-aged children in zahedan, southeast of iran

background: in iran, despite the use of vaccine since 1976, we are still having local epidemics especially in the children aged 15-20 years old. since 1996, the yearly epidemics of measles have been reported in these groups in sistan- baluchestan province, south east of iran. the present study was conducted to determinate the level of immunity in this target population in zahedan. methods: a total of 375 school-aged children were selected randomly from 8 schools in four areas of zahedan city, sistan-baluchestan province, iran, in 2000-1. sera were separated in laboratory and examined for measles antibody. the titers of antibody against measles were measured using hemaglutination inhibition method. a titer of 1:4 or more was considered as positive and protective to measles. results: a total of 298 samples (76.8%) were positive at the titer 1:4 or more. among 375 of total cases, 349 students (93%) were vaccinated twice and 26 cases (7%) were vaccinated once. only 78.6% of the former group was immune against measles and in the letter group, the titer of antibody was under the protective level. no significant correlation was found between seropositivity and sex ( p >0.05). conclusion: it is concluded that the present vaccination program (at 9 and 15 months of age) for production of immunity against measles in this area is insufficient. a new vaccination program (at the age of 12 months and 4-6 years of age) can bring under control the measles by increasing level immunity.