History and Objectives: Due to hepatitis B prevalence and complications resulting from the infection and the fact that prevention of the disease through vaccination has prime importance and because of reported discrepancy concerning the effectiveness of intradermal vaccination of hepatitis B, this study was conduced to compare the effectiveness of intradermal and intermuscular injection of the hepatitis B vaccine among female high school students of Kashan in 1996-1997.

Materials and Methods: In a clinical double-blind randomized trial on 200 students, HBsAg and HBSAb were measured by ELISA method before vaccination and positive cases were eliminated. Hundred and ninety students were randomly divided into two groups based on age and high school grade. In the experimental group, 0.1 ml of recombinant hepatitis B vaccine (Herber Biotech S.A Cuba) was injected by health center technicians intradermally at the three intervals of 0, 1 and 6 months in the flexor surface of forearm intradermally. In the control group, 1ml of the same vaccine with the same time intervals was injected intermuscularly by the same health technicians at the same deltoid region. Three weeks after the last injection, the effect of the vaccination was assessed by ELISA method by laboratory technicians who were unaware of the student group designations. Statistical Fischer test was conducted.

Results: The prevalence of HBsAg and HBSAb in population was 4.5 and 0.5% respectively. Experimental and control groups were matched on the basis of age and high school grade. The control group displayed 97.6% positive response, 1.2% weak positive response and 1.2% negative response, whereas the experimental group displayed 93.7%, 2.1% and 4.2% respectively. The differences were statistically significant.

Conclusion: It seems that due to a very small difference in the effectiveness of 2 methods and low cost of vaccination of intradermal injection, a larger size clinical trial is recommended. A study on the effectiveness of the time intervals for vaccination is also recommended.