Seroprevalence of neutralizing antibodies to measles virus in a vaccinated population in Iran, 1998.

Measles is an acute highly infectious viral disease. Although live attenuated vaccine is used throughout the world, outbreaks of disease still occur in many countries including Iran. In this cross-sectional study, by implementing a viral neutralization test and cell culture techniques, the seroprevalence of neutralizing anti-measles antibodies was assessed. Three hundred and fifty-four blood samples were collected and random-cluster classified from healthy subjects 6 months to 16 years old, residing in the town of Khodabandeh and its rural areas. Of the total subjects, 174 (49.2%) were girls and 180 (50.8%) were boys. From 354 subjects studied, 310 (87.6%) had neutralizing anti-measles antibody titer of 1:8 or higher and were considered to be immune and 44 (12.4%) had lower antibody titers. At the time of specimen collection, information with regards to age, sex, history of vaccination and place of residence were collected. Chi2 statistical test demonstrated a significant association between immune status and grouped age at the time of first vaccination (p < 0.009). The proportion test indicated significant differences in rate of seropositivity in paired age groups (3-8 vs. 9-11 and 9-11 vs. 12-64 months) (p < 0.02). The use of reliable techniques for assessing success of vaccination programs and performing seroepidemiological studies in order to organize national programs of control and eradication of measles are necessary.