tuberculin sensitivity in an urban population in iran

mantoux test using 2 iu of tuberculin prepared in iran was performed on 6675 healthy persons randomly selected from an urban population (shiraz) of iran. in 3776 persons with no evidence of previous bcg vaccination the rate of positive reaction was less than 2% up to the age of 14, slightly more than 2% among those 15-19 years of age, but strikingly higher (45.5%) in older age groups (p<0.001). the rate of positive reaction was higher among females (p<0.025). at the time of the study 2899 persons (43.3%) had received bcg. in this group the rate of positive reaction, being highest in the below 4 years old age group, dropped suddenly in the 5-10 year old age group and gradually increased thereafter to reach a high level (>90%) again. the differences between different age groups as well as the two sexes were statistically significant (p<0.005), though the sex difference was reversed in this group.