The aim of this project is to set up a cross-sectional cohort study (France, Germany, The Netherlands, Poland, Spain, Switzerland, Italy, United Kingdom and Portugal) to assess the implementation of EACS guidelines for HDV-testing among PLWH with positive HbsAg and thereby evaluate the prevalence of HDV infection among HIV/HBV-coinfected in 2023, as well as corresponding risk factors. In addition to the testing itself, this study will also set up a cohort and databasee for future HDV studies among PLWH, including clinical, virological und laboratory parameters. 1. Analyze the rate of HDV-testing and evaluate the prevalence of HDV-infection by testing. 1. Evaluation of former screening of HDV by assessing existing data at study sites. 2. Determination of the HDV prevalence in European PLWH and HBV coinfection. 2. Setting up a database of all PLWH with HBV/HDV coinfection 1. Analysis of transmission risk factors for HDV coinfection 2. Asses the rate of HDV positive patients with ongoing HDV replication. 3. Define the liver disease state by APRI score, fibroscan, ultrasound and routine laboratory test results.