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

Inclusion Criteria: * Age \> 18 years, * Presenting a chronic HDV infection (positive serology), * Who gave his written informed consent 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). Exclusion Criteria: * 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.