It has given researchers a better understanding of viral life cycle and has led to the development of improved therapy. Hepatitis B is the 9 th leading cause of death worldwide and there are more than 300 million chronic HBV carriers worldwide. This is due to the difference in the age of transmission. In Asia, HBV is vertically transmitted from mother to the infant.
Placenta is a potent barrier and transmission occurs at the time of childbirth.
In the United State, transmission occurs later in life with experimentation with sex and drug. The difference in the carrier states may be due to immature immune systems. As a result there are more incidence of hepatocellular carcinoma and cirrhosis in the Asian population. Hepatitis B can present as an acute, fulminant disease or in an asymptomatic chronic carrier. There is no recommended therapy for acute hepatitis but Lamivudine has been used in some cases.