Genomic characterization of hepatitis B virus from a vaccinated child in Nigeria suggests delayed neonatal immunoprophylaxis rather than vaccine escape: a case report

Background

Breakthrough hepatitis B virus (HBV) infections continue to be reported among vaccinated children in endemic settings. Although viral escape mutations are often suspected, delayed neonatal immunoprophylaxis and vertical transmission remain important but under-investigated mechanisms. Whole-genome sequencing provides an opportunity to distinguish between these competing explanations and strengthen molecular surveillance.