Hepatitis B Virus

Chronic hepatitis B virus (HBV) infection is a major health burden worldwide, with approximately 257 million people with chronic infection. HBV is a small partially double-stranded DNA virus that replicates within the nucleus of the hepatocyte and commonly leads to chronic infection. Chronic HBV infection can cause cirrhosis, hepatocellular carcinoma, and extrahepatic manifestations such as glomerulonephritis or vasculitis. The latter is due to deposition of circulating immune complex in the different tissues. The natural history of HBV infection can be conceptualized as a spectrum encompassing different phases, including immune tolerance, immune clearance, inactive carrier, and reactivation and resolution. The diagnosis of the different phases of chronic HBV infection relies on various HBV serologies, liver enzyme levels, and histology findings. There are currently eight therapies approved for the treatment of HBV. Tenofovir alafenamide was the most recently approved therapy with a better side effect profile compared with tenofovir disoproxil fumarate. With the recent advances in the basic research in hepatitis B, new treatment options may become available in the near-future. This review contains 9 figures, 11 tables and 80 references Key words: cirrhosis, entecavir, Hepadnaviridae, hepatitis B virus, hepatocellular carcinoma, precore mutation, tenofovir