Safety and Immunogenicity of Hepatitis B Vaccine: a Study on Iranian Navy Personnel

Objective: Preventing communicable diseases in the armed forces (AF) of a country is considered as a national interest and has a great importance. There are limited data on the efficacy of vaccination of the navy personnel. This study was designed to evaluate both the safety and the immunogenicity of a recombinant hepatitis B (HB) vaccine made by Pasteur Institute of Iran (IPI-rHB), in this target group. Methods: In this study, all members of two navy units were enrolled. After measuring their amount of primary antibody, the subjects were selected for vaccination. Finally, 108 male volunteers were surveyed who were all between 25 to 45 years of age. Three doses of IPI-rHB vaccine (1 ml containing 20µg of the recombinant antigen) were administered to the subjects who were serologically negative for HB markers. The vaccination was given intramuscularlyvia the deltoid muscle according to the 0, 1 and 6 months schedule. The subjects were carefully monitored to record any adverse reaction of the vaccine. Blood specimens were collected from each subject, 1 month after the second and third vaccinations, in order to determine the anti-HBs antibody response to the vaccine. The obtained serum was tested by ELISA to quantify anti-HBs antibodies raised in each subject. Results: The results showed that local pain, fever, erythema, induration, nausea, vomiting and headache were the significant side effects noted. Protective antibodies (anti-HBs) were detected with seroconversion and seroprotection rates of 52.9% and 47.1%, respectively after the second dose and seroconversion and seroprotection rates of 100% and 93.51% after the third dose of the vaccine. After completing the vaccination in 101 (93.51%) of the participants, antibody level was greater than 10 mIU/ml and in 7 (6.48%) subjects, the antibody level was between 1 and 10 mIU/ml. After the vaccination, the geometric mean titer of anti-HB antibody was 132.85. The seroprotection rate was 93.51% among the vaccinated population and 6.48% of the participants showed seroconversion. In this study, 22 (20.37%) subjects had anti-HBs titer of 10-100 mIU/ml and 79%(73.15%) subjects had anti-HBs titer of greater than100 mIU/ml. Although immunity to HB was achieved to a protective level among all the participants, the assessment of the long term immunity in AF members after complete vaccination is recommended. Conclusion: the results emphasized the importance of HB vaccination in adults, especially the AF members. Moreover, it reinforced the fact that three doses of HB vaccine is necessary to increase the seropositivity rate of anti-HBsAg in this group.