HIV AND HEPATITIS B CURE: Edited by Sharon R. Lewin and Peter A. RevillChallenges and opportunities for hepatitis B cure in the setting of HIV--hepatitis B virus co-infectionAudsley, Jennifera; Sasadeusz, Joeb,cAuthor Information aThe Peter Doherty Institute for Infection and Immunity, University of Melbourne and Royal Melbourne Hospital bDepartment of Infectious Diseases, The Alfred Hospital and Monash University cVictorian Infectious Disease Service, Royal Melbourne Hospital, at the Doherty Institute, Melbourne, Australia Correspondence to Jennifer Audsley, The Peter Doherty Institute for Infection and Immunity, University of Melbourne, 792 Elizabeth Street, Melbourne, VIC 3010, Australia. Tel: +61 3 83443266; fax: +61 3 93472952; e-mail: firstname.lastname@example.org Current Opinion in HIV and AIDS: May 2020 - Volume 15 - Issue 3 - p 193-199 doi: 10.1097/COH.0000000000000624 Buy Metrics Abstract Purpose of review To examine issues specific to HIV--HBV co-infection that are relevant to the search for and achieving hepatitis B cure in this the setting Recent findings In HIV--HBV co-infection, high rates of hepatitis B surface antigen (HBsAg) loss early after initiation of HBV-active antiretroviral therapy (ART) have previously been reported. Between 2012 and 2016, HBsAg loss from 2.8 to 23% was reported in numerous studies, including those already on suppressive HBV-active ART. Data published in 2018–2019 show that these rates have remained fairly stable (3.0–13.9%). However, it appears that higher HBsAg loss on starting HBV-active ART in co-infection falls within a few years to levels similar to that observed in long-term treated HBV mono-infection. Immune reconstitution and CD4+ T-cell recovery are likely to play a role in high HBsAg loss rates seen in early treated co-infection, although the mechanisms driving this are yet to be fully elucidated. Summary High rates of HBsAg loss early after HBV-active ART initiation is unique to HIV--HBV co-infection, making it the ideal setting to investigate underlying mechanisms of HBV loss and develop new HBV cure strategies. This phenomenon could be used to enhance HBsAg loss with new therapeutic approaches currently being investigated; however, this is obstructed by excluding co-infection from such studies. Copyright © 2020 Wolters Kluwer Health, Inc. All rights reserved.