key: cord-0856904-0jib6v93 authors: Lv, Xiu‐He; Yang, Jin‐Lin; Deng, Kai title: Letter to the Editor: unanswered questions about hepatitis B virus infection in patients with COVID‐19 date: 2021-08-13 journal: Hepatology DOI: 10.1002/hep.32098 sha: f3be21a91f7ec6ec013c272fdec2a709111c5c59 doc_id: 856904 cord_uid: 0jib6v93 We read with great interest of the study written by Yip et al (1). The authors answered some previously unanswered questions about COVID‐19 patients with hepatitis B virus (HBV) infection and thus had clear clinical implications. We think some questions still need to be answered further on this topic. The primary endpoint of this study was all‐cause mortality. Notably, the severity of disease in COVID‐19 patients was not discussed. The results of current studies on whether HBV infection increases disease severity in patients with COVID‐19 have been inconsistent, even in some studies with large samples from China (2,3). This article is protected by copyright. All rights reserved Another question is whether the presence of HBV-associated cirrhosis may associate with poor outcomes in COVID-19. Although liver cirrhosis was found to be associated with higher risk of mortality in the current study, the cause of cirrhosis was not distinguished. It also did not distinguish the clinical stages of current HBV infection. Recent study proved that the stage of liver disease is strongly associated with COVID-19 mortality (5) . For patients with advanced liver disease caused by HBV infection, whether the disease severity and mortality of COVID-19 are different from those of chronic hepatitis (or other etiologies) is still unknown. However, this would have significant clinical value in the monitoring and treatment of patients. In conclusion, we believe that the answers to the above questions can provide a more comprehensive understanding of the relationship between HBV infection and COVID-19. Current and past infections of hepatitis B virus do not increase mortality in patients with COVID-19 Epidemiological and clinical characteristics of 70 cases of coronavirus disease and concomitant hepatitis B virus infection: A multicentre descriptive study Association of liver abnormalities with in-hospital mortality in patients with COVID-19 Interaction between hepatitis B virus and SARS-CoV-2 infections Outcomes following SARS-CoV-2 infection in patients with chronic liver disease: An international registry study