Prevalence of occult hepatitis B infection and hepatitis B genotype characterization among blood donors in Jember Regency, East Java, Indonesia.

BACKGROUND: Despite extensive HBV vaccination efforts in Indonesia, the prevalence of occult hepatitis B virus infection (OBI) remains a concern, particularly among blood donors. This study investigated the prevalence of OBI, the distribution of circulating HBV genotypes, seropositivity for HBV-specific antibodies, and the potential influence of mutational characteristics on HBsAg secretion among blood donors in Jember, Indonesia. METHODS: A total of 330 HBsAg-negative blood donor samples from the Indonesian Red Cross in Jember were analyzed for HBV serological markers. Qualitative nested PCR and quantitative real-time PCR were used to detect HBV viral DNA and to measure viral load, respectively. HBV genotyping in positive samples was performed using Sanger sequencing of the S gene fragment. RESULTS: The analysis revealed an OBI prevalence of 3%. Serological testing indicated that 27% of participants were positive for anti-HBs antibodies, 18% for anti-HBc, and 6% for anti-HBc alone. All HBV DNA-positive cases belonged to genotype B, primarily sub genotypes B3 and B4. Phylogenetic analysis revealed multiple mutations in the HBV surface (S) gene and the reverse transcriptase (RT) domain of the polymerase (Pol) protein, including immune escape mutations, suggesting potential risks for HBV transmission and reactivation. CONCLUSIONS: These findings emphasize the need for enhanced screening, including NAT alongside serological testing, to mitigate OBI risks in blood donors and improve transfusion safety and public health policies in HBV-endemic regions of Indonesia.