Objectives: The 'EVoLVE' study set out to investigate the population prevalence of HBV infection, immunity and treatment eligibility in a rural South African setting.

Methods: We tested plasma samples from 2200 participants in a population-based study in KwaZulu-Natal, of whom 50% were living with HIV, for HBV surface antigen (HBsAg), HBV core antibody (anti-HBc), and HBV surface antibody (anti-HBs). For samples testing HBsAg-positive, we quantified alanine transferase (ALT) and HBV DNA viral load. We evaluated demographic and clinical correlates of HBV biomarkers, explored the geographical distribution of HBsAg, and assessed HBV treatment eligibility.

Results: Weighted HBV infection prevalence was 10.4% (95% CI: 9.0%-12.1%). Evidence of HBV exposure and clearance was found in 34.9% (95% CI: 32.4 - 37.5). Overall prevalence of vaccine-mediated HBV immunity was 8.9% (95% CI: 7.5%-10.4%) but for the sub-group born between 2000-2005 (after the HBV vaccine was implemented) this increased to 20.2% (95% CI 15.8-25.4). Infection prevalence was highest in the South of the region. Over 60% of individuals testing HBsAg-positive met treatment eligibility criteria.

Conclusion: Prevalence of HBV in this setting is high, while vaccine-mediated immunity is low. These data highlight a pressing need for scale-up of interventions to support progress towards elimination targets.

Keywords: HBV; South Africa; diagnosis; epidemiology; exposure; hepatitis B; immunity; infection; prevalence; screening; treatment; vaccine.