Epidemiology of hepatitis B virus (HBV) infections with particular regard to current routes of transmission and development of cirrhosis and malignancy.

The majority of hepatitis B virus (HBV) carriers world-wide becomes infected by transmission from asymptomatic carrier mother to infant, so-called "vertical" transmission, or early person to person so-called "horizontal" transmission, but sexual transmission is also important, especially in low endemicity areas. The histopathological findings at liver biopsies of these HBV-carriers vary from almost normal to severe chronic active hepatitis (CAH) with cirrhosis, and especially cirrhosis is associated with the development of HBV-related liver cancer. The reported annual incidence/100,000 of HBV-induced CAH in north-western Europe is 0.1-0.6 while the burden of the important chronic stages of hepatitis B is manyfold this in most developing countries.