 Design, Setting Subjects: A cross-sectional study and biomathematical modelling will be carried out. In the cross-sectional study, patients known to CHB carriers will be identified from the registries of the Ap Lei Chau, Aberdeen and Sai Yung Pun General Outpatient Clinics and Queen Mary Hospital. The biomathematical modelling will use a simulated cohort of patients aged 18 or above with CHB infections who may receive treatment in Hong Kong. Published data on the benefit of anti-viral treatments and the cross-sectional study data on preference-based health utility values of different stages of CHB infections will be used to estimate the cost-effectiveness of different treatment strategies using Markov modelling. 