Further evidence of hepatitis D occurring in the absence of hepatitis B.

The transmission of hepatitis D virus (HDV) requires a helper virus, hepatitis B virus (HBV) being the established companion. However, recent evidence suggests that HDV and other kolmioviruses might utilize a broader range of helper viruses, raising the possibility of unidentified disease associations. We screened anti-HDV antibodies (anti-HDV) from 2121 serum/plasma specimens, representing 1996 patients, selected from samples sent for routine diagnostic testing of various infectious and autoimmune diseases to the Virology and Immunology laboratory at HUS Diagnostic Center, Helsinki, Finland in 2021 -2022. This led to detection of anti-HDV in 20/1996 (1.0%) of patients, of which 17 were negative for both HBV surface antigen (HBsAg) and HBV DNA. Of these 17 patients, 16 were negative in HDV RNA detection, and 1 patient was HDV RNA positive. The HDV RNA positive patient was confirmed to be negative for HBV core total antibody, but positive for anti-HCV antibodies and HCV RNA. This serosurvey suggests HDV infections may occur outside HBV carriers.