History and Objectives: In light of effect of congenital rubella, various reports on the prevalence and augmented sensitivity to the disease and in order to determine the sensitivity to rubella among third and fourth year high school female students this study was carried out in Kashan in 1993.

Materials and Methods: A descriptive study by random sampling on 466 individuals was conducted. Individual profile including personal data, previous vaccination and rubella infection was recorded. Latex agglutination test (Rubellax, Oreon Diagnostics) was performed on blood samples taken from the individuals in order to measure the degree of sensitivity. Statistical analysis on the basis of 95% confidence interval was carried out.

Results: Of 466 individuals under the present study, 399 (85.6%) had immunity to rubella and 67 individuals (14.4%) were sensitive. Minimum and maximum confidence interval in the population was 11.2 and 17.6 percent respectively.

Conclusion: Due to prevalence of rubella sensitivity in the population and the fact that encounter with wild type virus will lead to permanent immunity and with time, reduced immunity will occur among immunized individuals, our data point out that immunized students displayed higher rate of sensitivity compared to non-immunized students. The importance of rubella immunization may be taken into question.