Comparative Review of Hepatitis B Virus Genotypes, Epidemiological Distribution, and Oncogenic Risks in India and Nigeria

Abstract

Hepatitis B virus (HBV) is the leading cause of chronic liver diseases, including hepatocellular carcinoma and cirrhosis, and it remains a serious global health threat. The virus exhibits a wide range of genetic diversity, with ten genotypes (A-J) and many subgenotypes showing distinct geographical distribution patterns and clinical implications. This comparative review highlights HBV genotypic variability and distribution in India and Nigeria, two highly endemic countries with different epidemiological molecular profiles. Recent and relevant literature from reputable scientific databases such as Scopus, Web of Science, PubMed, Google Scholar, and DOAJ was carefully and critically reviewed to explore genotype prevalence, routes of transmission, and clinical outcomes. Globally, genotypes A, B, C, D, and E contribute to nearly 96% of chronic HBV infections.

In India, D genotype predominates in most areas within the country, followed by the A genotype as a secondary type. Genotypes B and C are also found in some areas, showing a lot of regional variation. Nigeria, on the other hand, indicates a very similar dominance of the E genotype with low evidence of the A genotype, supporting phylogenetic evidence that the E genotype evolved in West Africa. These mutations have an impact on treatment response, disease progression, viral replication, and the risk of hepatocarcinogenesis. The review also highlights the significance of genotype-specific management plans by emphasizing the effect of genotype on antiviral resistance and immune response. Understanding these epidemiological molecular patterns is essential to developing successful immunization, surveillance, and treatment programs. Future research should focus on studies of antiviral resistance mechanisms and molecular profiling by using next-generation sequencing techniques to achieve HBV elimination goals by 2030 in Asia and Africa.