RecruitingNon-interventional Study to Assess the Number of People With Untreated/Unknown HBV + HDV and HCV in South-East AustriaThe HEAL-S study is a non-interventional study with retrospective data analysis. It consists of two parts. First a retrospective analysis based on nucleic acid testing (NAT) results will be performed. Two cohorts (HCV) and (HBV) will be established. Patients falling into one (or both) of the two cohorts will be invited to a prospective linkage-to-care study. In this part, patients are invited to the clinic, where the possibility of hepatitis treatment will be discussed.