Exploring the role of the ABO blood group types in hepatitis B virus infection: a systematic review

Introduction ABO blood groups have been associated with several disorders, including cancer, peptic ulcers, coagulopathy and infections. However, the mechanism of this association is unclear. This review examines the role ABO blood groups play in HBV infection. Methods A systematic search of seven electronic databases was conducted using the Population, Intervention/Exposure, Comparator, Outcome framework, including all studies published between 1974 and 2024. The review is registered in PROSPERO (ID: CRD420251243615). Results Thirty-five articles from seventeen countries across four continents were selected for review. Twelve of these demonstrated significant associations between ABO blood groups and HBV infection, with the majority investigating healthy blood donors. Disease progression to hepatic fibrosis and cirrhosis in individuals with chronic hepatitis B infection was associated with blood groups O and A. Conclusions Variable evidence linking ABO blood groups to HBV highlights the role of other factors. Links between ABO blood groups and HBV genotypes remain unclear.