Association of Routine Hepatitis B Vaccination and Other Effective Factors with Hepatitis B Virus Infection: 25 Years Since the Introduction of National Hepatitis B Vaccination in Iran

Background: One of the main health problems in the world is hepatitis B virus (HBV) infection. Vaccination and other factors can affect HBV infection. As various effective factors have been reported in different regions and studies, this study aimed to investigate the association between HBV infection and routine vaccination and other effective factors 25 years since the launch of the national vaccination program in Iran. Methods: This cross-sectional study, conducted in 2017 in Shiraz (Iran), investigated factors such as demographic variables such as gender, education, and occupation, vaccination status, and the potential risk factors for HBV infection. Hepatitis B surface antigen (HBsAg) and anti-hepatitis B core antibody (HBc Ab) tests were performed to determine HBV infection status. The data were analyzed using R software (version 3.5.2), using multivariate logistic regressions and machine learning methods. The level of significance was considered below 0.05. Results: A total of 2720 individuals were enrolled in the study (194 cases with HBV infection). Based on the logistic regression analyses, factors such as a family history of the disease (OR=2.53, P<0.001), vaccination (OR=0.57, P=0.004), a history of high-risk behaviors (OR=1.48, P=0.022), and occupation (OR=1.80, P=0.035) were significantly associated with HBV infection. Based on the conditional tree method, a family history of infection (P<0.001) and vaccination (P=0.023) were two important factors in classifying individuals for HBV infection. Conclusion: Based on the different methods applied in this study, HBV infection was affected by factors such as a family history of the disease, national HBV vaccination, and occupation. It appears that HBV vaccination, launched by the Iranian Ministry of Health and Medical Education in 1993, has reduced HBV infection.