National Cohort of Patients Co-infected With Hepatitis B and Delta Viruses

Who May Qualify: - Age \> 18 years, - Presenting a chronic HDV infection (positive serology), - Who gave his written willing to sign a consent form before any intervention and the day of inclusion at the latest, - Affiliated to Health Insurance or to the "Aide Médicale d'Etat" (request for exemption pending). Who Should NOT Join This Trial: - Patient participating in another biomedical research with an exclusion period ongoing at inclusion, - Vulnerable patient (minor, adults legally protected: under judicial protection, guardianship, or supervision, persons deprived of their liberty). - Patients with predictable difficulties of follow-up according to the investigator. Always talk to your doctor about whether this trial is right for you.