Infected Individuals - Individuals above 18 years and less than 65 years with chronic hepatitis B infection - Included according to undermentioned three arms: - Infected, On-treatment arm: subjects being treated with TAF/TDF for a minimum of 2 years with sustained viral suppression indicating adherence to therapy - Infected, Untreated control arm: Immune tolerant subjects; 15 with high viral load (>10^6) and 5 with low viral load (<10^6) - Uninfected Assay Validation controls: 10 subjects with history of prior infection who have convalesced i.e., have lost surface antigen, and developed surface antibody with viral eradication - Able and willing to provide informed consent Healthy Controls - Individuals above 18 years and less than 65 years who have never been infected and have been vaccinated - Able and willing to provide informed consent

• Individuals less than 18 years or greater than 65 years of age - Prior surgery to genitourinary tract, including prior vasectomy - Prior interferon therapy - HIV co-infection - Hepatitis C virus co-infection - Hepatitis delta virus co-infection