Protection Provided by Hepatitis B Vaccine in Adult Population of Chaharmahal and Bakhtiari Province, Iran in 2013.

Introduction: Hepatitis B vaccination has been integrated into National Expanded Program on Immunization in Iran since the year 1993 and young adult national vaccination project was done in 2008. So we have three subpopulations with vaccination coverage for hepatitis B and different antibody levels. Consisting of Subpopulation 1 born after 1993, subpopulation 2 born between 1989 and 1993 and receiving vaccination under adult national project, and subpopulation 3 born prior to the year 1989.

Aim: The present study was conducted to investigate community protection by hepatitis B vaccine in adult population in an accessible population in Iran and compare vaccination coverage, HBs Ab level, and its effective titration among the three above-mentioned subpopulations.

Materials And Methods: This cross-sectional study was done on a 3000-individual adult population from all seven counties of Chaharmahal and Bakhtiari province enrolled by clustering. After obtaining written consent and filling out a questionnaire of demographic data and history of hepatitis B vaccination by trained interviewers, necessary blood sample was taken and HBs Ab titration was checked. The data were analysed by chi-square in SPSS 19. The level of significance was considered as 0.05 and effective Ab titration as ≥ 10.

Results: The mean age of the participants was 38.4±16.3 years. Of the participants 48.2% had effective titration. For vaccination coverage, 77.4% were unvaccinated, 20% completely vaccinated, and 2.6% incompletely vaccinated with a significant association with effective titration (p<0.001). Eighty six percent of the subpopulation 1 and 79% of the subpopulation 2 were completely vaccinated, with a significant difference in effective titration between them (p<0.001). Vaccination coverage was higher in men and the single but equal in cities and villages. The effective titration was significantly associated with being married and residence place (p=0.003). There was a significant association between effective titration and the time at vaccination (p<0.001).

Conclusion: Protection provided by hepatitis B vaccine in adult population is relatively suitable especially in the youth population; however, catch-up programs of the groups exposed to risk are recommended.