Twenty-Year Trends in HBsAg Seroprevalence and Associated Risk Factors Among Blood Donors in Sistan and Baluchestan, Iran (2005 - 2024)

Abstract

Background: Long-term surveillance of transfusion-transmitted infections is essential, particularly in border regions. Objectives: This study analyzed 20-year trends in hepatitis B virus (HBV) seroprevalence and associated risk factors among blood donors in Sistan and Baluchestan Province, Iran, from 2005 to 2024. Methods: This retrospective analysis included 935,864 blood donors. Screening methods evolved from manual enzyme-linked immunosorbent assay (ELISA; 2005 - 2009) to automated ELISA beginning in 2009, chemiluminescence immunoassay (CLIA) beginning in 2019, and nucleic acid testing (NAT) beginning in 2024. A nested case-control study of 300 HBsAg-positive and 300 HBsAg-negative donors was analyzed using multivariable logistic regression. Results: The overall HBsAg seroprevalence was 0.634% (5,930/935,864). Annual prevalence declined from 2.039% in 2005 to 0.189% in 2024 (relative reduction > 90%; P < 0.001), reaching a minimum of 0.019% in 2019. First-time donors had a higher prevalence than repeat donors (1.861% vs 0.021%; P < 0.001). Independent risk factors included household contact with an HBV-infected person (adjusted odds ratio [aOR] = 54.5), drug abuse (aOR = 19.4), a history of jaundice (aOR = 8.1), and knife wounds (aOR = 7.3). Higher education was a protective factor. Conclusions: HBsAg seroprevalence decreased by more than 90% over two decades, reflecting the success of national vaccination and donor-selection strategies. Expanding the repeat-donor pool and maintaining NAT are essential for further improving blood safety.