Overview of Hepatitis B Virus, Clinical Features, and Host Immune Response

Abstract

Hepatitis B virus is a DNA virus that causes infection, often through exposure to infected blood, during sexual intercourse, and by vertical transmission of the virus from mother to child. After the incubation period of the virus, which lasts from 1 to 6 months, the prodrome stage appears in 10% - 20% of patients, which is characterized by fever, joint pain and the appearance of a rash. Then, at a later time, characteristic clinical and laboratory signs of acute hepatitis appear, which usually last from 1 month to 3 months. However, most of those infected are asymptomatically in the acute stage of disease, and the fact that they are carriers of the virus is discovered later, by chance. People with HBV infection may make a full recovery and their infection may be chronic, whether as carriers or as those with chronic hepatitis. Chronic infection appears in only 1% - 5% of adults who are exposed to HBV infection, while 95% of newborns develop chronic infection. About a third of people who suffer from chronic infection develop cirrhosis liver or liver cancer at a later time. And acute liver failure appears in less than 1% of patients. Infection with the HBV virus can manifest itself by the appearance of non-hepatic symptoms, such as arthritis, infection of the kidneys and vasculitis.

The aim of this reviewis to know the immune response against HBV and the ability of the virus to cause the damage in chronic cases.