Molecular Characteristics of Hepatitis B Virus among Children Vaccinated with HBsAg Positive in Huzhou, China

To the editor. Chronic liver diseases such as chronic hepatitis B, cirrhosis, and liver cancer caused by hepatitis B virus (HBV) infection pose a serious threat to public health. Mother-to-child transmission is one of the main routes of HBV dissemination. So far, immunoprophylaxis is an important strategy for preventing and controlling HBV infection. In China, the chronic HBV infection rate in children gradually decreased due to the universal implementation of the hepatitis B vaccine strategy since 1992. However, some studies have reported that mutations within the major hydrophilic region (MHR) region within the surface gene of HBV result in immune escape and contribute to immunoprophylaxis failure. Moreover, the genotype distribution is unequal in different areas in China. The HBV genotypes and surface gene mutation among children born after the universal HBV vaccination program have not been investigated in Huzhou, China. Thus, the present study was made up to delineate the molecular characteristics in vaccinated children with HBsAg positive in this area.