Hepatitis B Research Network Adult Cohort Study

Aims * Primary Aim: o To describe participants with hepatitis B virus (HBV) infection in a prospective cohort in the United States (US) and Canada and identify predictors of disease activation and progression * Secondary Aims: * To describe clinical, virological, and immunological characteristics of participants with HBV in the US and Canada * To evaluate changes in HBV infection status and quantitative hepatitis B surface antigen (HBsAg) levels and factors associated with those changes * To verify whether a baseline HBsAg below 1,000 IU/mL and HBV DNA below 1,000 IU/mL is an accurate predictor of people who are, or who will become, inactive carriers, defined as people who are HBsAg positive, hepatitis B "e" antigen (HBeAg) negative, have normal Alanine transaminase (ALT) and HBV DNA under 1,000 IU/mL on at least two occasions over a period of at least 6 months * To develop a bank of biospecimens (e.g., serum, plasma, DNA, lymphocytes, liver tissue) obtained from participants with HBV infection * To identify participants with HBV infection who are potential candidates in one of the treatment studies to be conducted by the Hepatitis B Research Network (HBRN) * To describe the natural history of hepatitis B infection in pregnancy including the frequency of, and clinical and virological characteristics associated with, hepatic flares during pregnancy and post-partum.