Molecular Variants for HBsAg: Surface and Subtype

Hepatitis B is a worldwide healthcare problem, especially in developing areas. An estimated one-third of the global population has been infected with this virus; approximately 350 million people are lifelong carriers, and only 2% spontaneously seroconvert annually. Hepatitis B virus (HBV) belongs to the hepadnavirus family of enveloped DNA viruses containing a partially double-stranded genome of 3182 ± 3221 bp depending on the genotype that encodes four overlapping open reading frames. HBV is classified into eight genotypes (A–H) that are geographically dispersed. Genotype A is predominant in North America, Western Europe, and Africa; genotypes B and C in Asia; genotype D in Southern Europe, Africa, and India; genotype E in West Africa; genotype F in Central and South America and Alaska; genotype G has been found in the United States, France, and Germany; and genotype H in Central America. Genotypes A, B, C, and D predominate in the United States, while the other genotypes are less common. Further detailed analysis of these HBsAg variants would provide further understanding of the antigenic structure of HBV