Prevalence of hepatitis B virus infection and treatment eligibility in Lesotho, Southern Africa: a population-based cross-sectional study with case-based follow-up

Background and aims: There is no data on hepatitis B virus (HBV) prevalence and treatment eligibility among the general population in Lesotho. We aimed to determine the prevalence of HBV infection in a large-scale cross-sectional survey among the general population in Lesotho, assess determinants of seropositivity, and evaluate treatment eligibility according to the 2024 WHO guidelines. Approach and results: We conducted a household-based, cross-sectional survey among participants≥10 years old in 120 randomly sampled village clusters in two districts. From participants screened positive for HBV surface antigen (HBsAg), we collected dried blood spots for HBV DNA measurement and referred the participants to health facilities for clinical assessment and treatment eligibility evaluation. Out of 6709 participants screened, 6705 had a valid HBsAg test result (3509 (52.3%) female, median age 33 years (IQR: 20–53)), which was positive in 78 participants, yielding a prevalence of 1.2% (95% CI: 0.9 to 1.4). Being≥18 years old, male, living in urban areas, living with HIV, consuming tobacco and belonging to higher wealth index quintiles, were associated with increasing odds of HBV infection. Of the 78 participants with HBV infection, 62 (79.5%) linked to care. Among these, 25/62 (40.3%) were also living with HIV and 23/25 (92%) already taking antiretroviral treatment active against HBV. Among the remaining, 10/37 (27.0%) were eligible for antiviral treatment based on HBV DNA, Aspartate aminotransferase to Platelet Ratio Index or alanine aminotransferase levels. Conclusions: We observed a low prevalence of HBV infection among Basotho. Treatment eligibility was high mostly due to the presence of HIV co-infection. However, nearly one-third of HBV mono-infected participants were eligible for treatment, suggesting a testing and treatment gap in this population.