Prevalence of Hepatitis B Core Antibody and Occult Hepatitis B Infection among Drug Users in Fars Province, Southwestern Iran, 2024.

Occult hepatitis B infection (OBI) is a significant issue in high-risk groups, including drug users. Therefore, the present study was conducted to assess the prevalence of OBI among drug users in Fars Province in 2024. In this cross-sectional study, 460 hepatitis B surface antigen (HBsAg)-negative individuals with a history of drug addiction were included. A questionnaire was completed for each participant to collect demographic, social, and behavioral information. Hepatitis B core antibody (anti-HBc) was assessed using an ELISA. Total DNA from serum samples that tested positive for anti-HBc was extracted and tested for hepatitis B virus DNA (HBV-DNA) using quantitative polymerase chain reaction (qPCR) testing. Moreover, peripheral blood mononuclear cells (PBMCs) were separated using the Ficoll gradient method, and their DNA was extracted, followed by qPCR testing. The mean age of the participants was 44.1 years (SD = 11.2; range: 13-85 years), whereas the mean age of anti-HBc-positive individuals was 51.2 years (SD = 9.2; range: 24-72 years). Among the participants, 82.6% were male. The frequency of anti-HBc was 15%, and it was significantly associated with age, history of injection drug use, medical service utilization, anti-hepatitis C virus positivity, HIV status, national hepatitis B vaccination time, and city of residence. No significant association was observed among sex, marital status, tattooing, or unsafe sexual practices. A qPCR analysis revealed undetectable HBV-DNA in all 64 serum samples of anti-HBc-positive subjects, whereas 1 out of 14 PBMC samples (7.1%) was positive for HBV-DNA. A 15% prevalence rate for resolved HBV infection was indicated in the present study, with no evidence of OBI in serum samples and a very low frequency of OBI in PBMCs.