Evidence for a change in the epidemiology of hepatitis B virus infection after nearly two decades of universal hepatitis B vaccination in South Africa

The hepatitis B vaccine has been part of the South African Expanded Program on Immunization since April 1995 but its long‐term impact remains unknown. This study tested 1,206 sera collected from patients aged 1–25 years from various health facilities across the country for HBV serological markers and HBV DNA. Based on the year the vaccine was introduced, samples were stratified by age into pre‐ and post‐vaccine introduction populations, which were then compared for evidence of immunity and chronic carriage using the Chi‐square test. Where HIV status was known, subset analyses were performed. Immunity to HBV infection increased from 13.0% in the pre‐ to 57.0% in the post‐vaccine introduction population (P