Molecular Characterisation of Hepatitis B Virus Genotypes and Drug Resistance Mutations in Treatment-Naive Patients in North West Nigeria

Hepatitis B virus (HBV) genotype diversity influences disease progression rates, treatment response to nucleos(t)ide analogues, and vaccine protection profiles. North West Nigeria has among the highest HBV surface antigen prevalence nationally, yet comprehensive HBV genotype and resistance data from this region remain absent from recent literature. This study molecularly characterises HBV genotypes and profiles pre-existing antiviral resistance mutations among treatment-naive HBsAg-positive patients in Kano, Sokoto, and Zamfara states. A cross-sectional molecular epidemiological design will recruit 300 HBsAg-positive, treatment-naive adults from hepatology clinics across the three states. HBV DNA will be extracted from serum and the full-length S gene and polymerase gene amplified by nested PCR and subjected to Sanger sequencing. Phylogenetic analysis will assign genotypes, and resistance-associated mutations in the reverse transcriptase domain (rtM204I/V, rtL180M, rtA181T) will be screened. Clinical data including HBV DNA levels, HBeAg status, and liver function tests will be correlated with genotype. Genotype E predominates in Nigerian HBV studies, but genotype A and mixed genotypes have been increasingly reported in northern populations, with implications for vaccine escape. Findings will characterise the HBV genetic landscape in North West Nigeria, informing treatment selection guidelines and contributing viral sequence data to the global HBV molecular epidemiology database. Keywords: Hepatitis B virus, genotyping, drug resistance mutations, North West Nigeria, molecular epidemiology