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We studied whether 48 weeks of PEG-IFN alfa-2a add-on increases HBsAg-decline and clearance in HBeAg-negative patients on long-term nucleo(s)tide analogue (NA) therapy. In this investigator-initiated, randomized, controlled trial conducted in Europe and Canada, HBeAg-negative patients treated with NA > 12 months, with HBVDNA < 200 IU/mL, were enrolled. Patients were randomized 2:1 to 48 weeks of PEG-IFN alfa-2a add-on (180 μg per week) or continued NA-monotherapy with subsequent follow-up to Week 72. Endpoints were HBsAg decline (≥1 log 10 IU/mL) and HBsAg clearance at Week 48. Of the 86 patients in the modified-intention-to-treat analysis, 58 patients received PEG-IFN add-on, and 28 continued NA monotherapy. At Week 48, 16(28%) patients achieved HBsAg decline ≥1 log 10 in the add-on arm versus none on NA-monotherapy (p < .001), and HBsAg clearance was observed in 6 (10%) PEG-IFN add-on patients versus 0% NA-monotherapy (p = .01). HBVRNA was only detected in 2% after PEG-IFN treatment versus 19% in NA-monotherapy (p = .002) at Week 48. PEG-IFN add-on therapy was well tolerated in majority of patients. Low baseline HBsAg levels (<10 IU/mL) identified patients most likely to achieve HBsAg loss with PEG-IFN add-on, whereas an HBsAg level > 200 IU/mL at on-treatment Week 12 was highly predictive of non-response (NPV = 100%). Addition of PEG-IFN to long-term NA enhanced HBsAg decline and increased the chance of HBsAg clearance in HBeAg-negative patients on long-term NA. On-treatment HBsAg levels >200 IU/mL identify patients unlikely to benefit from PEG-IFN add-on and could be used as a potential stopping-rule for PEG-IFN therapy. Our findings support further exploration of immune modulation add-on to antiviral therapy, preferably using response-guided strategies, to increase functional cure rates in patients with CHB., (© 2024 The Authors. Journal of Viral Hepatitis published by John Wiley & Sons Ltd.)

Immune-mediated liver damage is the driver of disease progression in patients with chronic hepatitis B virus (HBV) infection. Liver damage is an Ag-independent process caused by bystander activation of CD8 T cells and NK cells. How bystander lymphocyte activation is initiated in chronic hepatitis B patients remains unclear. Periods of liver damage, called hepatic flares, occur unpredictably, making early events difficult to capture. To address this obstacle, we longitudinally sampled the liver of chronic hepatitis B patients stopping antiviral therapy and analyzed immune composition and activation using flow cytometry and single-cell RNA sequencing. At 4 wk after stopping therapy, HBV replication rebounded but no liver damage was detectable. There were no changes in cell frequencies at viral rebound. Single-cell RNA sequencing revealed upregulation of IFN-stimulated genes (ISGs) and proinflammatory cytokine migration inhibitory factor (MIF) at viral rebound in patients that go on to develop hepatic flares 6-18 wk after stopping therapy. The type I IFN signature was only detectable within the liver, and neither IFN-α/β or ISG induction could be detected in the peripheral blood. In vitro experiments confirmed the type I IFN-dependent ISG profile whereas MIF was induced primarily by IL-12. MIF exposure further amplified inflammatory cytokine production by myeloid cells. Our data show that innate immune activation is detectable in the liver before clinically significant liver damage is evident. The combination of type I IFN and enhanced cytokine production upon MIF exposure represent the earliest immunological triggers of lymphocyte bystander activation observed in hepatic flares associated with chronic HBV infection., (Copyright © 2024 by The American Association of Immunologists, Inc.)

Introduction: Progress toward hepatitis C virus (HCV) elimination is impeded by low testing and treatment due to the current diagnostic pathway requiring multiple visits leading to loss to follow-up. Point-of-care testing technologies capable of detecting current HCV infection in one hour are a 'game-changer.' These tests enable diagnosis and treatment in a single visit, overcoming the barrier of multiple visits that frequently leads to loss to follow-up. Combining point-of-care HCV antibody and RNA tests should improve cost-effectiveness, patient/provider acceptability, and testing efficiency. However, implementing HCV point-of-care testing programs at scale requires multiple considerations., Areas Covered: This commentary explores the need for point-of-care HCV tests, diagnostic strategies to improve HCV testing, key considerations for implementing point-of-care HCV testing programs, and remaining challenges for point-of-care testing (including operator training, quality management, connectivity and reporting systems, regulatory approval processes, and the need for more efficient tests)., Expert Opinion: It is exciting that single-visit testing, diagnosis, and treatment for HCV infection have been achieved. Innovations afforded through COVID-19 should facilitate the accelerated development of low-cost, rapid, and accurate tests to improve HCV testing. The next challenge will be to address barriers and facilitators for implementing point-of-care testing to deliver them at scale.

Curative hepatitis C virus (HCV) therapy has increased transplantation from HCV-infected nucleic acid test-positive donors to HCV-uninfected recipients (D+/R-). We evaluated outcomes of early and late HCV treatment among D+/R- nonliver organ transplants. Patients received HCV regimens per local standard (n = 10 sites). Outcomes were compared between early and late treatments. Early treatment regimens (ETR) (n = 56) were initiated pretransplantation to day 7 posttransplant. Late treatment regimens (LTRs) (n = 102) began median 31 (range, 8-114) days posttransplant. There were 79 kidney, 50 lung, 23 heart, and 6 mixed transplants, similar between groups. HCV RNA was quantifiable in 98% of LTR versus 44.6% of ETR recipients (P < .001). Mean (range) days on treatment were 28 (7-93) ETR and 81 (51-111) LTR (P < .0001). There were no virological failures with ETR, but relapse (n = 3) and nonresponse (n = 2) in LTR (P = .16), including fibrosing cholestatic hepatitis postrelapse (n = 1). Sustained virological response was 100% (95% confidence interval, 93.4-100.0) in ETR (n = 54) and 94.9% (95% confidence interval, 88.5-98.3) in LTR (n = 98). Acute rejection occurred in 11 (19.6%) ETR and 25 (24.5%) LTR. In total, 11 HCV-unrelated deaths occurred: 8 ETR and 3 LTR. Organ transplantation from HCV-infected nucleic acid test-positive donors to HCV-uninfected recipients was safe. ETR led to fewer virological failures with shorter treatment duration, supporting recommendations to initiate treatment promptly posttransplant., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Background: Migrants from hepatitis B virus (HBV) endemic regions are at high risk of having chronic infection. Despite this, HBV knowledge and awareness programming, and low-barrier screening methods such as point of care (POC) testing, among this group have yet to become routine., Methods: We conducted a mass HBV POC screening and knowledge and awareness campaign for individuals of Chinese descent in Toronto, Canada. POC screening was administered, then participants completed a knowledge questionnaire. Logistic regression identified associations between demographic factors and participants' level of HBV knowledge., Results: From 2015 to 2018, 33 outreach events resulted in 891 individuals completing testing and the knowledge questionnaire. Individuals averaged 64.4 years old. Most, 62% ( N = 552), were female, and 73.6% ( N = 656) have been in Canada for <30 years. The average questionnaire score was 70.7% correct, with 65.2% ( N = 581) demonstrating a high level of HBV knowledge. Post-secondary education (OR: 2.19, 95% CI: 1.41, 3.39), income of $50,000 to <$75,000 (OR: 2.74, 95% CI: 1.39, 5.43), and having familial history of HBV (OR: 1.72, 95% CI: 1.06, 2.78) were associated with high knowledge. The observed prevalence of HBV was 1.5%, with 13 individuals testing positive on the POC test and confirmatory laboratory testing., Conclusions: Improving knowledge and awareness of HBV is critical to empowering people, especially migrants who experience barriers to care, to pursue vaccination, testing, and treatment. Combining knowledge outreach and POC test campaigns, enabled discussion and screening for HBV with large numbers of people, and can be tailored for optimal effectiveness for specific groups., Competing Interests: JJF has received consulting support from AbbVie, Enanta, Gilead, Janssen, and Roche, and research funding from AbbVie, Abbott, Gilead, and Enanta. BEH has received consulting support from Intercept, Cymabay, Mirum, Albireo, Chemomab, and Caliditas, and research support from Intercept, Cymabay, Mirum, and Albireo. HLAJ has received research support from AbbVie, Arbutus, Bristol Myers, Squibb, Gilead Sciences, Janssen, Merck, and Roche, and consulting support from Aligos, Arbutus, Arena, Eiger, Enyo, Gilead Sciences, GlaxoSmithKline, Janssen, Merck, Regulus, Roche, VBI Vaccines (Variation Biotechnologies), Vir Biotechnology, Inc, and Viroclinics. DW reports research support from Gilead, BMS, Vertex, and Boehringer. MJB has received research support from AbbVie, Gilead Sciences and Cepheid. CY has received consulting fees from Abbvie, and patient education grant from Gilead., (© Canadian Association for the Study of the Liver, 2024.)

Competing Interests: MJ Biondi reports receiving research support and consulting fees from AbbVie, Gilead, Abbott, Specialty Rx Solutions, and McKesson Canada. JJ Feld reports receiving research support and consulting fees from AbbVie and Gilead. No other competing interests were declared.

Background: Current guidelines recommend HCV screening by 18 months of age for those exposed to HCV in utero; yet, screening occurs in the minority of children., Objectives: To evaluate the association between maternal neighbourhood-level social determinants of health (SDOH) and paediatric HCV screening in the general population in a publicly funded healthcare system in Canada., Methods: Retrospective cohort study using administrative healthcare data held at ICES. Children born to individuals positive for HCV RNA in pregnancy from 2000 to 2016 were identified and followed for 2 years. Major SDOH were identified, and the primary outcome was HCV screening in exposed children (HCV antibody and/or RNA). Associations between SDOH and HCV screening were determined using multivariate Poisson regression models adjusting for confounding., Results: A total of 1780 children born to persons with +HCV RNA were identified, and 29% (n = 516) were screened for HCV by age two. Most mothers resided in the lowest income quintile (42%), and most vulnerable quintiles for material deprivation (41%), housing instability (38%) and ethnic diversity (26%) with 11% living in rural locations. After adjustment for confounding, maternal rural residence (risk ratio [RR] 0.82, 95% confidence interval [CI] 0.62, 1.07) and living in the highest dependency quintile (RR 0.83, 95% CI 0.65, 1.07) were the SDOH most associated with paediatric HCV screening. Younger maternal age (RR 0.98 per 1-year increase, 95% CI 0.97, 0.99), HIV co-infection (RR 1.69, 95% CI 1.16, 2.48) and GI specialist involvement (RR 1.18, 95% CI 1.00, 1.39) were associated with higher probabilities of screening., Conclusions: Among children exposed to HCV during pregnancy, rural residences and living in highly dependent neighbourhoods showed a potential association with a lower probability of HCV screening by the age of 2. Future work evaluating barriers to paediatric HCV screening among rural residing and dependent residents is needed to enhance the screening., (© 2024 The Authors. Paediatric and Perinatal Epidemiology published by John Wiley & Sons Ltd.)

Background and Aims: Historical paired liver biopsy studies are likely to underestimate current progression of disease in patients with chronic hepatitis C virus (HCV) infection. We aimed to assess liver disease progression according to the non-invasive Fibrosis-4 (FIB-4) index in patients with chronic HCV and early disease., Methods and Results: Patients diagnosed with chronic HCV and FIB-4 <3.25 from four international liver clinics were included in a retrospective cohort study. Follow-up ended at start of antiviral therapy resulting in sustained virological response, at time of liver transplantation or death. Primary outcome of advanced liver disease was defined as FIB-4 >3.25 during follow-up. Survival analyses were used to assess time to FIB-4 >3.25.In total, 4286 patients were followed for a median of 5.0 (IQR 1.7-9.4) years, during which 41 071 FIB-4 measurements were collected. At baseline, median age was 47 (IQR 39-55) years, 2529 (59.0%) were male, and 2787 (65.0%) patients had a FIB-4 <1.45. Advanced liver disease developed in 821 patients. Overall, 10-year cumulative incidence of advanced disease was 32.1% (95% CI 29.9% to 34.3%). Patients who developed advanced disease showed an exponential FIB-4 increase. Among patients with a presumed date of HCV infection, cumulative incidence of advanced disease increased 7.7-fold from 20 to 40 years as opposed to the first 20 years after HCV infection., Conclusions: The rate of advanced liver disease is high among chronic HCV-infected patients with early disease at time of diagnosis, among whom liver disease progression accelerated over time. These results emphasise the need to overcome any limitations with respect to diagnosing and treating all patients with chronic HCV across the globe., Competing Interests: Competing interests: LK, NSE, CW, SvH, OC, JV and RAdM report no conflict of interest. RM received financial compensation for consultancy from AbbVie. AP is an employee of Merck & Co. RJdK declares that the Erasmus University Medical Center, on behalf of RJdK, received honoraria for consulting/speaking from Gilead, Janssen-Cilag, Bristol-Myers Squibb (BMS), AbbVie, MSD, Roche and Norgine, and received research grants from Gilead, Janssen-Cilag, BMS and Roche. BEH has consulted for and received grant/research support from Intercept Pharmaceuticals. SZ reports consultancies for AbbVie, BMS, Gilead, Janssen and Merck. TV has received grants from Gilead Sciences and BMS; is a consultant for Janssen Pharmaceuticals, Gilead Sciences, AbbVie and BMS; and a sponsored lecturer for W L Gore, Gilead Sciences, BMS and AbbVie. HLAJ has served as consultant for and has received grants from AbbVie, Arbutus, BMS, Enyo, Gilead Sciences, Janssen, Medimmune, Merck, Roche, Vir Biotechnology and Viroclinics. JJF has consulted for Abbott, AbbVie, Gilead, Enanta and Roche; and has received grant/research support from AbbVie, Eiger, Gilead, Janssen and Wako/Fujifilm. AJvdM received financial compensation for lecture activities for Zambon and research funding from Gilead, MSD, AbbVie and Zambon., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: There are no immunological biomarkers that predict control of chronic hepatitis B (CHB). The lack of immune biomarkers raises concerns for therapies targeting PD-1/PD-L1 because they have the potential for immune-related adverse events. Defining specific immune functions associated with control of HBV replication could identify patients likely to respond to anti-PD-1/PD-L1 therapies and achieve a durable functional cure., Methods: We enrolled immunotolerant, HBeAg+ immune-active (IA+), HBeAg- immune-active (IA-), inactive carriers, and functionally cured patients to test ex vivo PD-1 blockade on HBV-specific T cell functionality. Peripheral blood mononuclear cells were stimulated with overlapping peptides covering HBV proteins +/-α-PD-1 blockade. Functional T cells were measured using a 2-color FluoroSpot assay for interferon-γ and IL-2. Ex vivo functional restoration was compared to the interferon response capacity assay, which predicts overall survival in cancer patients receiving checkpoint inhibitors., Results: Ex vivo interferon-γ+ responses did not differ across clinical phases. IL-2+ responses were significantly higher in patients with better viral control and preferentially restored with PD-1 blockade. Inactive carrier patients displayed the greatest increase in IL-2 production, which was dominated by CD4 T cell and response to the HBcAg. The interferon response capacity assay significantly correlated with the degree of HBV-specific T cell restoration., Conclusions: IL-2 production was associated with better HBV control and superior to interferon-γ as a marker of T cell restoration following ex vivo PD-1 blockade. Our study suggests that responsiveness to ex vivo PD-1 blockade, or the interferon response capacity assay, may support stratification for α-PD-1 therapies., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

Background & Aims: Patients with chronic hepatitis B (CHB) are at increased risk of hepatocellular carcinoma and (liver-related) mortality. In addition to hepatitis B-related factors, metabolic comorbidities may contribute to the progression of fibrosis. Therefore, we studied the association between metabolic comorbidities and adverse clinical outcomes in patients with CHB., Methods: We conducted a retrospective cohort study of CHB patients attending the Erasmus MC University Medical Center (Rotterdam, The Netherlands) and CHB patients who underwent liver biopsy at the Toronto General Hospital (Toronto, Canada). The presence of metabolic comorbidities (ie, overweight, diabetes mellitus, hypertension, and dyslipidemia) was assessed based on chart review. The primary end point was liver-related events, defined as the first composite of hepatocellular carcinoma, liver transplantation, or liver-related mortality., Results: We analyzed 1850 patients, of whom 926 (50.1%) were overweight, 161 (8.7%) had hypertension, 116 (6.3%) had dyslipidemia, and 82 (4.4%) had diabetes. During a median follow-up period of 7.3 years (interquartile range, 2.9-11.5 y), a total of 111 first events were recorded. Hypertension (hazard ratio [HR], 8.3; 95% CI, 5.5-12.7), diabetes (HR, 5.4; 95% CI, 3.2-9.1), dyslipidemia (HR, 2.8; 95% CI, 1.6-4.8), and overweight (HR, 1.7; 95% CI, 1.1-2.5) were associated with an increased risk for liver-related events. The presence of multiple comorbidities further increased the risk. Findings were consistent for patients with and without cirrhosis, among noncirrhotic hepatitis B e antigen-negative patients with hepatitis B virus DNA less than 2000 IU/mL and in multivariable analysis adjusting for age, sex, ethnicity, hepatitis B e antigen status, hepatitis B virus DNA, use of antiviral therapy, and the presence of cirrhosis., Conclusions: Metabolic comorbidities in CHB patients are associated with an increased risk for liver-related events, with the highest risk observed in patients with multiple comorbidities. Findings were consistent in various clinically relevant subgroups, underscoring the need for thorough metabolic assessment in patients with CHB., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objective: Reinfection poses a challenge to hepatitis C virus (HCV) elimination. This analysis assessed incidence of, and factors associated with reinfection among people treated for recent HCV (duration of infection <12 months)., Methods: Participants treated for recent HCV (primary infection or reinfection) in an international randomized trial were followed at 3-monthly intervals for up to 2 years to assess for reinfection. Reinfection incidence was calculated using person-time of observation. Factors associated with HCV reinfection were assessed using Cox proportional hazards regression analysis., Results: Of 222 participants treated for recent HCV, 196 (62% primary infection, 38% reinfection) were included in the cohort at risk for reinfection, of whom 87% identified as gay or bisexual men, 71% had HIV and 20% injected drugs in the month prior to enrolment. During 198 person-years of follow-up, 28 cases of HCV reinfection were identified among 27 participants, for an incidence of 14.2 per 100 person-years [95% confidence interval (CI) 9.8-20.5]. Reinfection was associated with prior HCV reinfection [adjusted hazards ratio (aHR) 2.42; 95% CI 1.08-5.38], injection drug use posttreatment (aHR 2.53; 95% CI 1.14-5.59), condomless anal intercourse with casual male partners (aHR 3.32; 95% CI 1.14-9.65) and geographic region (United Kingdom, aHR 0.21; 95% CI 0.06-0.75). Among gay and bisexual men (GBM), reinfection was also associated with sexualized drug use involving injecting posttreatment (aHR 2.97; 95% CI 1.10-8.02)., Conclusion: High reinfection incidence following treatment for recent HCV among people with ongoing sexual and drug use risk behaviour highlights the need for posttreatment surveillance, rapid retreatment of reinfection and targeted harm reduction strategies., (Copyright © 2023 Wolters Kluwer Health, Inc. All rights reserved.)

Background: We evaluated the proportion, clinical features, and outcomes of previously healthy children presenting to a large Canadian quaternary pediatric center with severe acute hepatitis of unknown etiology., Methods: All patients with serum alanine aminotransferase (ALT) > 500 U/L or aspartate aminotransferase (AST) > 500 U/L between June 1, 2018, and May 31, 2022, at The Hospital for Sick Children, were identified. Subjects with only AST > 500 U/L were excluded. Clinical characteristics, investigations, and outcomes for patients without clear etiology for ALT > 500 U/L (severe acute hepatitis of unknown etiology) for our study period and from October 1 to May 31 of each year 2018-2021 were reviewed., Results: Of 977 patients with ALT/AST> 500 U/L, 720 had only ALT > 500 U/L. We excluded age below 6 months (n = 99) or above 16 years (n = 66), known pre-existing liver conditions (n = 66), and ALT > 500 U/L in already admitted patients (n = 151). Among the remaining 338 children with ALT > 500 U/L at presentation, an etiology was identified in 303 subjects. 33 (9.8%) children [median age 6.1 y (range 0.5-15.5); 61% male] were confirmed as severe acute hepatitis of unknown etiology. Twenty patients (60.6%) were tested for blood adenovirus by PCR, and 1 (5%) was positive (serotype B7). Liver tissue specimens from 18 patients revealed no evidence of viral inclusions or adenovirus. Twelve (36.3%) presented with pediatric acute liver failure, with 8 (24.2%) requiring liver transplantation. There were no deaths. Hepatitis-associated aplastic anemia occurred in 5 (15%) patients., Conclusions: Of children presenting with severe acute hepatitis to a quaternary children's hospital over a 48-month period, 9.8% had unknown etiology with no change over time. Liver transplantation remains an important treatment strategy for those presenting with pediatric acute liver failure phenotype. The frequency of cases associated with human adenovirus infection was noncontributory., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of the American Association for the Study of Liver Diseases.)

Introduction: Exploration of sexual and drug use behaviours following treatment for recent hepatitis C virus (HCV) is limited. This analysis modelled behavioural trajectories following treatment for recent HCV and assessed reinfection., Methods: Participants treated for recent HCV in an international trial (enrolled 2017-2019) were followed at 3-monthly intervals for up to 2 years to assess longitudinal behaviours. Population-averaged changes were assessed using generalized estimating equations. Distinct behavioural trajectories were identified using group-based trajectory modelling. HCV reinfection incidence was calculated using person-years (PY) of observation., Results: During the follow-up of 212 participants (84% gay and bisexual men [GBM]; 69% HIV; 26% current injecting drug use [IDU]), behavioural trajectories for IDU and stimulant use (past month) did not change. However, population-averaged decreases in the likelihood of daily IDU (adjusted odds ratio [AOR] 0.83; 95% CI 0.72, 0.95) and opioid use (AOR 0.84; 95% CI 0.75, 0.93) were observed. Among GBM, behavioural trajectories for chemsex did not change. Population-averaged decreases in condomless anal intercourse with casual male partners (CAI-CMP) (AOR 0.95; 95% CI 0.90, 0.99) and group-sex (AOR 0.86; 95% CI 0.80, 0.93) were observed, but masked distinct trajectories. While a proportion had a decreased probability of CAI-CMP (23%) and group-sex (59%) post-treatment, a substantial proportion retained a high probability of these behaviours. High HCV reinfection incidence was observed for the sustained high probability IDU (33.0/100 PY; 95% CI 17.7, 61.3) and chemsex (23.3/100 PY; 95% CI 14.5, 37.5) trajectories., Conclusions: Limited sexual and drug use behavioural change was observed following treatment for recent HCV, supporting access to surveillance and (re)treatment., (© 2023 The Authors. Journal of the International AIDS Society published by John Wiley & Sons Ltd on behalf of the International AIDS Society.)

Introduction: Despite improvements in the management of chronic hepatitis B (CHB), risk of cirrhosis and hepatocellular carcinoma remains. While hepatitis B surface antigen loss is the optimal end point, safe discontinuation of nucleos(t)ide analog (NA) therapy is controversial because of the possibility of severe or fatal reactivation flares., Methods: This is a multicenter cohort study of virally suppressed, end-of-therapy (EOT) hepatitis B e antigen (HBeAg)-negative CHB patients who stopped NA therapy (n = 1,557). Survival analysis techniques were used to analyze off-therapy rates of hepatic decompensation and differences by patient characteristics. We also examined a subgroup of noncirrhotic patients with consolidation therapy of ≥12 months before cessation (n = 1,289). Hepatic decompensation was considered related to therapy cessation if diagnosed off therapy or within 6 months of starting retreatment., Results: Among the total cohort (11.8% diagnosed with cirrhosis, 84.2% start-of-therapy HBeAg-negative), 20 developed hepatic decompensation after NA cessation; 10 events were among the subgroup. The cumulative incidence of hepatic decompensation at 60 months off therapy among the total cohort and subgroup was 1.8% and 1.1%, respectively. The hepatic decompensation rate was higher among patients with cirrhosis (hazard ratio [HR] 5.08, P < 0.001) and start-of-therapy HBeAg-positive patients (HR 5.23, P < 0.001). This association between start-of-therapy HBeAg status and hepatic decompensation remained significant even among the subgroup (HR 10.5, P < 0.001)., Discussion: Patients with cirrhosis and start-of-therapy HBeAg-positive patients should be carefully assessed before stopping NAs to prevent hepatic decompensation. Frequent monitoring of viral and host kinetics after cessation is crucial to determine patient outcome., (Copyright © 2023 by The American College of Gastroenterology.)

Hepatitis B (HBV) is a major cause of global morbidity and mortality, and the leading cause of liver cancer worldwide. Significant advances have recently been made toward the development of a finite HBV treatment that achieves permanent loss of HBsAg and HBV DNA (so-called "HBV cure"), which could provide the means to eliminate HBV as a public health threat. However, the HBV cure is just one step toward achieving WHO HBV elimination targets by 2030, and much work must be done now to prepare for the successful implementation of the HBV cure. In this review, we describe the required steps to rapidly scale-up future HBV cure equitably. We present key actions required for successful HBV cure implementation, integrated within the World Health Organization (WHO) Global Health Sector Strategy (GHSS) 2022-2030 framework. Finally, we highlight what can be done now to progress toward the 2030 HBV elimination targets using available tools to ensure that we are preparing, but not waiting, for the cure., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Global elimination of hepatitis C virus (HCV) will be difficult to attain without an effective HCV vaccine. Controlled human infection (CHI) studies with HCV were not considered until recently, when highly effective treatment became available. However, now that successful treatment of a deliberate HCV infection is feasible, it is imperative to evaluate the ethics of establishing a program of HCV CHI research. Here, we evaluate the ethics of studies to develop an HCV CHI model in light of 10 ethical considerations: sufficient social value, reasonable risk-benefit profile, suitable site selection, fair participant selection, robust informed consent, proportionate compensation or payment, context-specific stakeholder engagement, fair and open collaboration, independent review and oversight, and integrated ethics research. We conclude that it can be ethically acceptable to develop an HCV CHI model. Indeed, when done appropriately, developing a model should be a priority on the path toward global elimination of HCV., Competing Interests: Potential conflicts of interest. C. W. reports consulting income from Cardialen, Eli Lilly & Company, and the Research Triangle Institute International. J. F. reports research funding from AbbVie, Gilead, and the Canadian Institutes for Health Research Planning and Dissemination Grant and holding an unpaid position as the president of the Canadian Association for the Study of the Liver. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2023.)

Competing Interests: Potential conflicts of interest. D. L. T. reports funding support from the National Institutes of Health (NIH) and National Institute on Drug Abuse; royalties or licenses from UpToDate; consulting fees from Merck and Co, Excision Bio, and Evrys; payments from the Masur et al Infectious Diseases Board Review; payments for testimony from various entities; participation in a Merck and Co Data and Safety Monitoring Board; and holding a leadership role with the Conference on Retroviruses and Opportunistic Infections (CROI) Program Committee and African Mission Healthcare. N. H. S. reports grant support from the Canadian Institutes of Health Research (CIHR) (PJT-173467) and the NIH (U01AI131313, R01AI136533, and U19AI159819). J. J. F. reports funding support from CIHR Planning and Dissemination grant 183426, grants or contracts from AbbVie and Gilead, and consulting fees from AbbVie and Gilead, and is the president of the Canadian Association for the Study of the Liver. T. J. L. reports no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed.

Background: In 2019, about 58 million individuals were chronically infected with hepatitis C virus. Some experts have proposed challenge trials for hepatitis C virus vaccine development., Methods: We modeled incremental infections averted through a challenge approach, under varying assumptions regarding trial duration, number of candidates, and vaccine uptake. We computed the benefit-risk ratio of incremental benefits to risks for challenge versus traditional approaches. We also benchmarked against monetary costs of achieving incremental benefits through treatment., Results: Our base case assumes 3 vaccine candidates, each with an 11% chance of success, corresponding to a 30% probability of successfully developing a vaccine. Given this probability, and assuming a 5-year difference in duration between challenge and traditional trials, a challenge approach would avert an expected 185 000 incremental infections with 20% steady-state uptake compared to a traditional approach and 832 000 with 90% uptake (quality-adjusted life-year benefit-risk ratio, 72 000 & 323 000). It would cost at least $92 million and $416 million, respectively, to obtain equivalent benefits through treatment. BRRs vary considerably across scenarios, depending on input assumptions., Conclusions: Benefits of a challenge approach increase with more vaccine candidates, faster challenge trials, and greater uptake., Competing Interests: Potential conflicts of interest. A. B. reports grants to Brown University From One Day Sooner and from the Centers for Disease Control and Prevention/Council of State and Territorial Epidemiologists (grant NU38OT000297-02). R. S. reports a grant to Brown University from One Day Sooner. A. M. reports participating in a postdoctoral fellowship with the Canadian Network on Hepatitis C (CanHepC) and the Canadian Institutes of Health Research (CIHR); CanHepC is funded by a joint initiative of the CIHR (NPC-178912) and the Public Health Agency of Canada. J. F. reports research funding from AbbVie, Gilead, and CIHR (planning and dissemination grant 18342683426) and also reports holding an unpaid position as president of the Canadian Association for the Study of the Liver. J. A. S. reports receiving a grant for their institution from the National Institute on Drug Abuse, National Institutes of Health. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

In a hepatitis C virus (HCV)-controlled human infection model (CHIM), healthy volunteers are inoculated with HCV and then treated. Residual hepatocellular carcinoma (HCC) risk after viral clearance is an important consideration when evaluating the CHIM. We estimate HCC risk in spontaneously cleared HCV and in noncirrhosis after sustained virological response (SVR) to HCV treatment in a systematic review and using data from 3 cohorts: German anti-D, Taiwan, and US Veterans Affairs (VA). For noncirrhosis SVR, the overall HCC rate is 0.33 per 100 patient-years in meta-analysis. HCC rates for the German, Taiwan, and US Veterans Affairs cohorts are 0, 0.14, and 0.02 per 100 patient-years, respectively. Past hepatitis B virus exposure was not accounted for in the Taiwan cohort, while VA patients were likely tested based on liver disease/risk factors, which may confound HCC outcomes. The German cohort with no HCC after 44 years is most comparable to the CHIM participants. Although it is difficult to precisely estimate HCC risk from an HCV CHIM, the data suggest the risk to be very low or negligible., Competing Interests: Potential conflicts of interest. M. W. received study materials with no payment for research. J. F. reports research funding from AbbVie, Gilead, and the Canadian Institutes for Health Research Planning and Dissemination Grant and holding an unpaid position as the president of the Canadian Association for the Study of the Liver. D. E. K. reports grants or contracts from Gilead Sciences, Inc, AstraZeneca, Glycotest, Inc, Genentech, and Exact Sciences. All other authors report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (Published by Oxford University Press on behalf of Infectious Diseases Society of America 2023.)

The design of a clinical trial for a controlled human infection model (CHIM) to accelerate hepatitis C virus (HCV) vaccine development requires careful consideration. The design of a potential approach to HCV CHIM is outlined, involving initial sentinel cohorts to establish the safety and curability of the viral inoculum followed by larger cohorts to establish the spontaneous clearance rate for each inoculum. The primary endpoint would be HCV clearance by 24 weeks post-inoculation, recognizing that the prevention of chronic infection would be the primary goal of HCV vaccine candidates. Additional considerations are discussed, including the populations to be enrolled, the required monitoring approach, indications for antiviral therapy, and the required sample size for different CHIM approaches. Finally, safety considerations for CHIM participants are discussed., Competing Interests: Potential conflicts of interest . J. B. reports funding through the Canadian Institutes of Health Research and Gilead Sciences. They also report honoraria payment for giving a presentation from Gilead Sciences. They report participation in a Data and Safety Monitoring Board (DSMB) with AbbVie, Gilead Sciences, and Cepheid Sciences and a board role with the International Network on Hepatitis and Health for Substance Abusers. D. L. T. reports research funding support from the National Institutes of Health (NIH) and National Institute on Drug Abuse (NIDA); royalties or licenses with UpToDate; consulting fees from Merck and Co, Excision Bio, and Evrys; honoraria payments from Masur et al Infectious Diseases Board Review; and participation on a DSMB with Merck and Co; and holds a leadership role with the Conference on Retroviruses and Opportunistic Infections (CROI) Program Committee and the African Mission Healthcare. G. J. D. reports clinical trial grants from Gilead Sciences, AbbVie, and Merck. They also report being an associate editor with the Journal of Hepatology. J. J. F. reports receiving a Canadian Institutes of Health Research Planning and Dissemination Grant (1183426). They report receiving grants and consulting fees from AbbVie and Gilead and is the past president of the Canadian Association for the Study of the Liver. M. S. reports receiving the NIH midcareer mentoring award, K24DA034621. They report receiving research grants to Johns Hopkins University from Janssen, Vir, Assembly Bio, and AbbVie, and also received consulting fee payments from AbbVie, Assembly Bio, Aligos Antios, Arbutus, Gilead, Precision Bio, and GSK for participation in a Scientific Advisory Board related to hepatitis V virus (HBV) and HCV. They also participated in a DSMB related to HIV and HBV with Gilead and Immunocore and is the American editor for the Journal of Viral Hepatitis. B. H. and M. G. G. report no potential conflicts. All authors have submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest. Conflicts that the editors consider relevant to the content of the manuscript have been disclosed., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.)

Objective: To evaluate uptake of hepatitis C virus (HCV) testing and treatment among psychiatry inpatients at Canada's largest mental health institution, the Centre for Addiction and Mental Health (CAMH)., Methods: We reviewed medical records for all forensic and long-stay mental health patients from January 2017 to May 2021 to examine rates of HCV testing (antibody and RNA), treatment, and follow-up and completed a logistical regression to identify predictors associated with HCV antibody (Ab) screening among inpatients., Results: Of 1,031 patients, 73% (n = 753) were male, mean age was 44 years (range: 20-92), and mean length of stay was 7.1 months (range: 0 days-24 years). Most, 83% (n = 856), were diagnosed with schizophrenia spectrum disorders. In total, 652/1,031 (63%) of individuals in this cohort received HCV Ab screening. When broken down by admission rather than individual, 570/1,303 (44%) forensic admissions had an associated HCV Ab screening, and 318/1,450 (22%) non-forensic admissions had an associated HCV Ab screening. Individuals admitted to a forensic unit and those diagnosed with schizophrenia or substance use disorders were more likely to undergo HCV Ab screening, while individuals of Asian ethnicity were less likely (all P  < .05). HCV Ab positivity was 4.9%, and most (84%, n = 27) HCV Ab-positive individuals had subsequent RNA testing, of whom 56% (n = 15) tested HCV RNA positive. Of 15 RNA-positive individuals, 10 initiated treatments, 7 on-site at CAMH and 3 at a local hepatology center. A total of 7 individuals (1 treated by specialists and 6 on-site) achieved sustained virological response or cure. The remaining 3 were lost to follow-up, 2 of whom were treated at the hepatology clinic., Conclusions: Based on the high prevalence of HCV, mental health inpatients should be included in groups for whom universal screening is recommended. Since on-site treatment was more successful than referral to external hepatology specialists, utilizing inpatient admission as an opportunity for HCV screening and treatment should receive more consideration., (© Copyright 2023 Physicians Postgraduate Press, Inc.)

Background: Few countries have implemented the necessary policy changes to reduce the number of steps in the cascade of care to achieve hepatitis C virus (HCV) elimination, including Canada. The aim of this study was to describe and compare legislation, scope of practice, and policy as it relates to the provision of HCV care in each province., Methods: We reviewed grey literature and regulatory and legislative documents which affect various aspects of the HCV cascade of care. Findings were verified by content experts., Results: HCV RNA reflex testing ensures those that are antibody positive get an HCV RNA test; however only 80% of provinces have reflex test. Point-of-care antibody testing can be offered in most community non-health care settings, yet many types of health care providers are unable to do this independently. Following a positive test, it may not be feasible to complete venipuncture; however only a single province processes HCV RNA dried blood spot cards. In many provinces, training and verification are required for novice prescribers, and in some provinces prescribing continues to be restricted to specialists. Only a single province has task-shifted treatment to a non-physician non-nurse practitioner model, where pharmacists can prescribe treatment. Finally, 80% of provinces require authorization forms, and 30% require proof of investigations for treatment., Conclusions: No single province is optimizing the use of diagnostic tools and task shifting and decreasing paperwork to expedite treatment initiation. Collaboration between provinces is needed to streamline practice, update policy, and promote equity in HCV diagnosis, care, and treatment., Competing Interests: MJ Biondi reports receiving research support and consulting fees from AbbVie, Gilead, and Specialty Rx Solutions. CH Dale is a paid employee of McKesson Canada, and receives consulting fees from AbbVie and Gilead. H Shah reports receiving consulting fees and research support from AbbVie and Gilead. JJ Feld reports receiving research support and consulting fees from AbbVie and Gilead. HLA Janssen reports receiving research support from AbbVie and Gilead. The other authors have nothing to disclose., (© Canadian Association for the Study of the Liver, 2023.)

Background: Direct-acting antiviral (DAA) therapies have simplified HCV treatment, and publicly funded Canadian drug plans have eliminated disease-stage restrictions for reimbursement of DAA therapies. However other policies which complicate, delay, or prevent treatment initiation still persist. We aim to describe these plans' existing reimbursement criteria and appraise whether they hinder treatment access., Methods: We reviewed DAA reimbursement policies of 16 publicly funded drug plans published online and provided by contacts with in-depth knowledge of prescribing criteria. Data were collected from May to July 2022. Primary outcomes were: (1) if plans have arranged to accept point-of-care HCV RNA testing for diagnosis; testing requirements for (2) HCV genotype, (3) fibrosis stage, and (4) chronic infection; (5) time taken and method used to approve reimbursement requests; (6) providers eligible to prescribe DAAs; and (7) restrictions on re-treatment., Results: Fifteen (94%) plans have at least one policy in place which limits simplified HCV treatment. Many plans continue to require results of genotype or fibrosis staging, limit eligible prescribers, and take longer than 1 day to approve coverage requests. One plan discourages treatment for re-infection., Conclusion: Reimbursement criteria set by publicly funded Canadian drug plans continue to limit timely, equitable access to HCV treatment. Eliminating clinically irrelevant pre-authorization testing, expanding eligible prescribers, expediting claims processing, and broadening coverage of treatment for reinfection will improve access to DAAs. The federal government could further enhance efforts by introducing a federal HCV elimination strategy or federal high-cost drug PharmaCare program., Competing Interests: SR Bartlett has advised and spoken for Gilead Sciences and AbbVie (all personal payments given as unrestricted donations to BC Centre for Disease Control Foundation for Public Health) and has received investigator-initiated research funding from Gilead Sciences and AbbVie via her institution. CL Cooper has advised, spoken for, and received unrestricted clinical and research funding from Gilead Sciences and AbbVie. N Kronfli receives research funding from Gilead Sciences, advisory fees from Gilead Sciences, ViiV Healthcare, Merck, and AbbVie, and speaker fees from Gilead Sciences, AbbVie, and Merck, all outside of the submitted work. J Butler-McPhee has advised Gilead Sciences and Abbvie, and has received unrestricted research funding from Gilead Sciences, all outside of the submitted work. J Grebely is a consultant/advisor and has received research grants from AbbVie, Biolytical, Camurus, Cepheid, Gilead Sciences, Hologic, Indivior, and Merck, all outside the submitted work. All other authors have no other relevant interests to disclose. J Feld is a consultant/advisor and has received research grants from Gilead and AbbVie., (© Canadian Association for the Study of the Liver, 2023.)

Background and Aims: Hepatitis B virus (HBV) reactivation has been reported in patients co-infected with hepatitis C virus (HCV) during direct acting antiviral (DAA) therapy, leading the United States Food and Drug Administration (U.S. FDA) to issue a black box warning on all DAA drug labels recommending monitoring for HBV reactivation. We conducted a comprehensive evaluation to assess the rate of HBV reactivation among patients with chronic hepatitis C (CHC) during DAA therapy., Methods: Patients with CHC and recovered HBV infection (hepatitis B surface antigen negative (HBsAg)/anti-hepatitis B core positive), treated with DAAs were included if stored sera were available. Samples were tested for HBV DNA, HBsAg, and ALT. HBV reactivation was considered if (1) HBV DNA was undetectable pre-DAA therapy and became detectable post-therapy, or (2) HBV DNA was detectable pre-treatment, but not quantifiable (< 20 IU/mL) and became quantifiable post-treatment., Result: 79 patients with median age of 62 years were included. 68% were male and Caucasian. Various DAA regimens were administered for 12-24 weeks. Reactivation occurred in 8/79 (10%) of patients and occurred more frequently in men compared to women: 6 during treatment and 2 after treatment. Neither an ALT flare nor HBsAg seroreversion were observed. Detectable HBV DNA was transient in 5/8 and could not be determined in 3/8 but ALT flares were not observed in follow-up of these patients., Conclusion: The risk of HBV reactivation was low in CHC patients with resolved HBV during DAA therapy. Our data support testing for HBV DNA only in selected patients with ALT flares or failure of ALT normalization during DAA treatment., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

A functional cure of chronic hepatitis B defined as sustained hepatitis B surface antigen loss after finite course of therapy is rarely achieved with current therapy but is the goal of novel treatments. Understanding the virological and immunological mechanisms of hepatitis B virus persistence has enabled the identification of novel treatment targets, drug discovery, and the evaluation of novel agents in clinical trials. Lessons were learned from early phase 1 and phase 2 trials regarding the antiviral activity and safety profile of these agents. There is a strong rationale to combine agents to reduce viral replication, reduce viral antigen load, invigorate immune responses, and induce specific adaptive immune responses. Nucleos(t)ide analogs will likely remain an essential backbone of future combinations to control viral replication and prevent resistance to antiviral drugs. In this review, we discuss perspectives on approaches to achieving functional cure, with a review of virological and immunological strategies, highlighting challenges and unresolved questions with the various attempts to achieve cure, as well as exploring alternative endpoints such as partial cure and new noninvasive viral and immunological biomarkers to stratify patients and predict/monitor antiviral response., (Copyright © 2023 AGA Institute. Published by Elsevier Inc. All rights reserved.)

Introduction: Withdrawal of nucleos(t)ide analog therapy is increasingly being evaluated in chronic hepatitis B infection as a strategy to induce hepatitis B surface antigen (HBsAg) loss. The Hepatitis B Research Network Immune-Active Trial evaluated treatment with tenofovir (TDF) for 4 years ± an initial 6 months of peginterferon-α (PegIFN) (NCT01369212) after which treatment was withdrawn., Methods: Eligible participants (hepatitis B e antigen [HBeAg]-/anti-HBe+, hepatitis B virus [HBV] DNA <10 3 IU/mL, no cirrhosis) who discontinued TDF were followed for at least 1 year with optional follow-up thereafter. Retreatment was based on predefined criteria., Results: Among 201 participants who received 4 years of treatment, 97 participants (45 TDF and 52 TDF + PegIFN arm, 79 Asian) discontinued TDF. HBsAg loss occurred in 5 participants, 2 within 25 weeks and 3 within 89-119 weeks postwithdrawal (cumulative rate 4.3% by 2 years). Alanine aminotransferase (ALT) flares (>5× upper limit of normal) after TDF withdrawal occurred in 36 (37.1%) participants and occurred more frequently and earlier in those HBeAg- compared with HBeAg+ at treatment initiation. ALT flares were associated with older age and higher HBV DNA pretreatment and at the visit before the flare. ALT flares were not significantly associated with HBsAg decline or loss but were associated with immune active disease at 1 year (70.6% vs 11.9%, P < 0.0001) and 2 years (66.7% vs 25.9%, P = 0.03) postwithdrawal. Treatment reinitiation was required in 13 (13.4%) participants, and 13 others remained in a sustained inactive carrier state by the end of the study follow-up. No criteria reliably predicted safe treatment withdrawal., Discussion: Results from this trial do not support TDF withdrawal as a therapeutic strategy. HBsAg loss was infrequent within 2 years of stopping long-term TDF. If withdrawal is considered, HBV DNA should be carefully monitored with reinitiation of therapy if levels rise above 4 log 10 IU/mL to reduce the risk of ALT flares, as they were not associated with subsequent HBsAg decline or loss., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc. on behalf of The American College of Gastroenterology.)

Background & Aims: Novel therapies for chronic hepatitis B (CHB), such as RNA interference, target all viral RNAs for degradation, whereas nucleoside analogues are thought to block reverse transcription with minimal impact on viral transcripts. However, limitations in technology and sampling frequency have been obstacles to measuring actual changes in HBV transcription in the liver of patients starting therapy., Methods: We used elective liver sampling with fine-needle aspirates (FNAs) to investigate the impact of treatment on viral replication in patients with CHB. Liver FNAs were collected from patients with CHB at baseline and 12 and 24 weeks after starting tenofovir alafenamide treatment. Liver FNAs were subjected to single-cell RNA sequencing and analysed using the Viral-Track method., Results: HBV was the only viral genome detected and was enriched within hepatocytes. The 5' sequencing technology identified protein-specific HBV transcripts and showed that tenofovir alafenamide therapy specifically reduced pre-genomic RNA transcripts with little impact on HBsAg or HBx transcripts. Infected hepatocytes displayed unique gene signatures associated with an immunological response to viral infection., Conclusions: Longitudinal liver sampling, combined with single-cell RNA sequencing, captured the dynamic impact of antiviral therapy on the replication status of HBV and revealed host-pathogen interactions at the transcriptional level in infected hepatocytes. This sequencing-based approach is applicable to early-stage clinical studies, enabling mechanistic studies of immunopathology and the effect of novel therapeutic interventions., Impact and Implications: Infection-dependent transcriptional changes and the impact of antiviral therapy on viral replication can be measured in longitudinal human liver biopsies using single-cell RNA sequencing data., Competing Interests: SK, JJW, and PM are employees of Gilead Sciences. AJG has received research funding from Gilead Sciences, Janssen Pharmaceuticals, and GSK, and performs consulting/scientific advisory services for Janssen Pharmaceuticals, Roche, GSK, Vir Biotech, Virion Therapeutics, and Bluejay Therapeutics. HLAJ received research funding from AbbVie, Gilead Sciences, GlaxoSmithKline, Janssen, Roche, and Vir Biotechnology Inc., and performs consulting/scientific advisory services for Aligos, Antios, Arbutus, Eiger, Gilead Sciences, GlaxoSmithKline, Janssen, Merck, Roche, VBI Vaccines, Vir Biotechnology Inc., and Viroclinics. JJF received research funding from Abbvie, Gilead, GlaxoSmithKline, Janssen, Roche, Eiger, and Enanta, and performs consulting/scientific advisory services for Abbvie, Antios, Arbutus, Eiger, Enanta, Bluejay, GSK, Janssen, and Roche. SF receives speaking/teaching fees from Gilead Sciences and research funding from Gilead Sciences, and performs consulting/scientific advisory services for Gilead Sciences, Abbvie, Janssen, Spring Bank, Pfizer, and Novo-Nordisk. Please refer to the accompanying ICMJE disclosure forms for further details., (© 2023 The Author(s).)

A hepatitis C virus (HCV) vaccine is urgently needed. Vaccine development has been hindered by HCV's genetic diversity, particularly within the immunodominant hypervariable region 1 (HVR1). Here, we developed a strategy to elicit broadly neutralizing antibodies to HVR1, which had previously been considered infeasible. We first applied a unique information theory-based measure of genetic distance to evaluate phenotypic relatedness between HVR1 variants. These distances were used to model the structure of HVR1's sequence space, which was found to have five major clusters. Variants from each cluster were used to immunize mice individually, and as a pentavalent mixture. Sera obtained following immunization neutralized every variant in a diverse HCVpp panel (n = 10), including those resistant to monovalent immunization, and at higher mean titers (1/ID 50 = 435) than a glycoprotein E2 (1/ID 50 = 205) vaccine. This synergistic immune response offers a unique approach to overcoming antigenic variability and may be applicable to other highly mutable viruses.

Background and Aims: Whether entecavir (ETV) and tenofovir disoproxil fumarate (TDF) differentially affect relapse and outcomes following treatment discontinuation across different patient subpopulations remains unclear. We aimed to compare rates of off-therapy hepatitis B surface antigen (HBsAg) loss, virological and clinical relapse, and retreatment between chronic hepatitis B (CHB) patients who discontinued TDF or ETV therapy., Methods: This study included 1402 virally suppressed CHB patients who stopped either ETV (n = 981) or TDF (n = 421) therapy between 2001 and 2020 from 13 participating centers across North America, Europe, and Asia. All patients were hepatitis B e antigen-negative at treatment discontinuation. Inverse probability of treatment weighting was used to balance the treatment groups. Outcomes were analyzed using survival methods., Results: During a median off-treatment follow-up of 18 months, HBsAg loss occurred in 96 (6.8%) patients overall. Compared with ETV, TDF was associated with a higher rate of HBsAg loss (P = .03); however, the association was no longer significant after statistical adjustment (P = .61). Virological relapse occurred earlier among TDF-treated patients (P < .01); nonetheless, rates became comparable after the first year off therapy (P = .49). TDF was significantly associated with a higher clinical relapse rate than ETV throughout follow-up (P < .01). The development of a virological or clinical relapse did not affect the rate of HBsAg loss. Retreatment rates were not significantly different between the treatment groups., Conclusions: TDF and ETV have differential relapse patterns but are associated with similar rates of HBsAg loss and retreatment following discontinuation. Finite therapy can be considered for CHB patients on either TDF or ETV therapy., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)

Objectives: People who inject drugs (PWID) are at a high risk of hepatitis C virus (HCV) infection. HCV cure is associated with improved patient-reported outcomes (PROs), but there are little data among PWID. This study aimed to assess the change in PROs during and after HCV direct-acting antiviral (DAA) treatment., Methods: This analysis used data from 2 clinical trials of DAA treatment in PWID. PROs assessed included health-related quality of life, social functioning, psychological distress, housing, and employment. Generalized estimating equations and group-based trajectory modeling were used to assess changes in PROs over time., Results: No significant changes in the 3-level version of EQ-5D scores, EQ visual analogue scale scores, social functioning, psychological distress, and housing were observed over the 108-week study period. There was a significant increase in the proportion of participants employed (18% [95% confidence interval (CI) 12%-23%] at baseline to 28% [95% CI 19%-36%] at the end of the study). Participants were more likely to be employed at 24 weeks and 108 weeks after commencing treatment. Having stable housing increased the odds of being employed (odds ratio 1.70; 95% CI 1.00-2.90). The group-based trajectory modeling demonstrated that most outcomes remained stable during and after DAA treatment., Conclusions: Although no significant improvement was identified in health-related quality of life after HCV DAA treatment, there was a modest but significant increase in employment during study follow-up. The study findings support the need for multifaceted models of HCV care for PWID addressing a range of issues beyond HCV treatment to improve quality of life., (Copyright © 2023. Published by Elsevier Inc.)

Background & Aims: Most patients in the immunotolerant (IT) phase of chronic hepatitis B (CHB) transition to the immune active (IA-hepatitis B surface antigen [HBeAg]+) phase by early adulthood. We examined characteristics of adults in the IT vs IA-HBeAg+ phase and rate of transition from IT to other phases of CHB, with a focus on those ≥40 years., Methods: Demographic, clinical, and virologic characteristics of participants in the Hepatitis B Research Network adult cohort study with IT CHB (alanine aminotransferase ≤1.5 × upper limit of normal, hepatitis B virus DNA >10 7 IU/mL) were compared by age category, and to those with IA-HBeAg+ CHB in cross-sectional analysis. This study received institutional review board approval at all participating centers., Results: Of 107 adult IT participants, 52 (48%) were <30, 33 (31%) were 30 to 39, and 22 (21%) were ≥40 years old (maximum, 71 years). Among IT groups, the proportion born in Asia and duration of CHB were greater in older IT groups, but virologic and liver disease characteristics were similar. Compared with IA-HBeAg+ participants (n = 192), IT participants were younger, fewer were men, more were Asian, and platelets, qHBsAg, and qHBeAg levels were higher. Similar differences were observed when comparisons were made with the ≥40 years IT group. Among IT participants, 60 (56%) transitioned during 206 person-years of follow-up. The phase transition rate per 100 person-years was highest in the <30 years group (33.0 [95% confidence interval [CI], 23.4-46.7]) vs the 30 to 39 years group (24.8 [95% CI, 15.6-39.4]) and ≥40 group (27.4 [95% CI, 14.8-50.9]), but 95% CIs overlapped., Conclusions: In a large North American population, over 50% of adults in the IT phase of CHB were ≥30 years and 20% were ≥40 years old, but older IT patients had similar characteristics and rates of transition as younger IT patients., (Copyright © 2023. Published by Elsevier Inc.)

Background: Despite high burden of Hepatitis C (HCV) among people who inject drugs, significant barriers to care persist. The aim of this study was to evaluate the provision of rapid, low-barrier point-of-care (POC) HCV RNA testing and linkage to care among clients of a supervised consumption service (SCS) located within a community health centre in Toronto, Canada. Secondary aims included measuring HCV RNA prevalence at baseline, HCV incidence during follow-up and exploring factors associated with HCV RNA positivity and treatment uptake., Methods: Participants were enrolled in a prospective, observational cohort from August 13, 2018 to September 30, 2021. Those with positive HCV RNA tests were offered immediate referral to onsite treatment. Those with negative results were offered repeat testing every three months for up to four visits. HCV incidence was estimated as the number of incident HCV infections per 100 person-years at risk, among those HCV RNA negative at baseline who returned for ≥1 follow-up visit. Missing data were reported when present., Findings: 128 participants were enrolled with four later removed due to ineligibility. At baseline, 54 of 124 eligible participants (43.5%) tested HCV RNA positive. HCV incidence was 35.1 cases per 100 person-years (95% CI: 18.9-65.3) with a cumulative incidence of 38.3% at 15 months of follow-up. Among participants HCV RNA positive at baseline or follow-up (n = 64), 67.2% (n = 43) were linked to HCV care and treatment was initiated among 67.4% (n = 29/43)., Interpretation: High HCV RNA prevalence and incidence demonstrate that the SCS serves a high-risk population for HCV. Testing acceptance was high, as was treatment engagement. POC HCV RNA testing positions SCSs as an important point of HCV care access., Funding: HCV Micro-Elimination Grant, Gilead Sciences Canada; in-kind support from Cepheid., Competing Interests: JJF reports research support and honoraria for consulting from Abbvie and Gilead. JP received the grant from Gilead Sciences Canada and the in-kind donation of the testing platform from Cepheid to conduct the study., (© 2023 The Author(s).)

Background: COVID-19 has hindered hepatitis C virus (HCV) and HIV screening, particularly in marginalised groups, who have some of the highest rates of these conditions and lowest rates of COVID-19 vaccination. We assessed the acceptability of combining HCV testing with COVID-19 vaccination in a centre for addiction services (CAS) in Barcelona and a mobile testing unit (MTU) in Madrid, Spain., Methods: From 28/09/2021 to 30/06/2022, 187 adults from marginalised populations were offered HCV antibody (Ab) testing along with COVID-19 vaccination. If HCV Ab+, they were tested for HCV-RNA. MTU participants were also screened for HIV. HCV-RNA+ and HIV+ participants were offered treatment. Data were analysed descriptively., Results: Findings show how of the 86 CAS participants: 80 (93%) had been previously vaccinated for COVID-19, of whom 72 (90%) had the full first round schedule; none had a COVID-19 vaccine booster and all received a COVID-19 vaccine; 54 (62.8%) were tested for HCV Ab, of whom 17 (31.5%) were positive, of whom all were tested for HCV-RNA and none were positive. Of the 101 MTU participants: none had been vaccinated for COVID-19 and all received a COVID-19 vaccine; all were tested for HCV Ab and HIV and 15 (14.9%) and 9 (8.9%) were positive, respectively; of those HCV Ab+, 9 (60%) were HCV-RNA+, of whom 8 (88.9%) have started treatment; 5 (55.6%) of those HIV+ had abandoned antiretroviral therapy, of whom 3 (60%) have re-started it., Conclusions: The intervention was accepted by 54 (62.8%) CAS participants and all MTU participants and can be used in marginalised communities., (© 2023. The Author(s).)

Background: The role of viral hepatitis status in post-hepatectomy outcomes has yet to be delineated. This large, multicentred contemporary study aimed to evaluate the effect of viral hepatitis status on 30-day post-hepatectomy complications in patients treated for hepatocellular carcinoma (HCC)., Methods: Patients from the National Surgical Quality Improvement Program (NSQIP) database with known viral hepatitis status, who underwent hepatectomy for HCC between 2014 and 2018, were included. Patients were classified as HBV-only, HCV-only, HBV and HCV co-infection (HBV/HCV), or no viral hepatitis (NV). Multivariable models were used to assess outcomes of interest. The primary outcome was any 30-day post-hepatectomy complication. The secondary outcomes were major complications and post-hepatectomy liver failure (PHLF). Subgroup analyses were performed for cirrhotic and noncirrhotic patients., Results: A total of 3234 patients were included. The 30-day complication rate was 207/663 (31.2%) HBV, 356/1077 (33.1%) HCV, 29/81 (35.8%) HBV/HCV, and 534/1413 (37.8%) NV (p = 0.01). On adjusted analysis, viral hepatitis status was not associated with occurrence of any 30-day post-hepatectomy complications (ref: NV, HBV odds ratio (OR) 0.89 [95% confidence interval (CI): 0.71-1.12]; HCV OR 0.91 [95% CI: 0.75-1.10]; HBV/HCV OR 1.17 [95% CI: 0.71-1.93]). Similar results were found in cirrhotic and noncirrhotic subgroups, and for secondary outcomes: occurrence of any major complications and PHLF., Conclusions: In patients with HCC managed with resection, viral hepatitis status is not associated with 30-day post-hepatectomy complications, major complications, or PHLF compared with NV. This suggests that clinical decisions and prognostication of 30-day outcomes in this population likely should not be made based on viral hepatitis status., (© 2022. Society of Surgical Oncology.)

Background: COVID-19 presents with a breadth of symptomatology including a spectrum of clinical severity requiring intensive care unit (ICU) admission. We investigated the mucosal host gene response at the time of gold standard COVID-19 diagnosis using clinical surplus RNA from upper respiratory tract swabs., Methods: Host response was evaluated by RNA-sequencing, and transcriptomic profiles of 44 unvaccinated patients including outpatients and in-patients with varying levels of oxygen supplementation were included. Additionally, chest X-rays were reviewed and scored for patients in each group., Results: Host transcriptomics revealed significant changes in the immune and inflammatory response. Patients destined for the ICU were distinguished by the significant upregulation of immune response pathways and inflammatory chemokines, including cxcl2 which has been linked to monocyte subsets associated with COVID-19 related lung damage. In order to temporally associate gene expression profiles in the upper respiratory tract at diagnosis of COVID-19 with lower respiratory tract sequalae, we correlated our findings with chest radiography scoring, showing nasopharygeal or mid-turbinate sampling can be a relevant surrogate for downstream COVID-19 pneumonia/ICU severity., Conclusions: This study demonstrates the potential and relevance for ongoing study of the mucosal site of infection of SARS-CoV-2 using a single sampling that remains standard of care in hospital settings. We highlight also the archival value of high quality clinical surplus specimens, especially with rapidly evolving COVID-19 variants and changing public health/vaccination measures., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts., (© The Author(s) 2023. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: As First Nations Peoples are a priority focus of Canada's commitment to eliminating hepatitis C virus (HCV) as a public health threat, understanding individuals' progression from diagnosis to cure can guide prioritization of elimination efforts. We sought to characterize and identify gaps in the HCV care cascade for Status First Nations peoples in Ontario., Methods: In this retrospective cohort study, a partnership between the Ontario First Nations HIV/AIDS Education Circle and academic researchers, HCV testing records (1999-2018) for Status First Nations peoples in Ontario were linked to health administrative data. We defined the cascade of care as 6 stages, as follows: tested positive for HCV antibody, tested for HCV RNA, tested positive for HCV RNA, HCV genotyped, initiated treatment and achieved sustained viral response (SVR). We mapped the care cascade from 1999 to 2018, and estimated the number and proportion of people at each stage. We stratified analyses by sex, diagnosis date and location of residence. We used Cox regression to analyze the secondary outcomes, namely the associations between undergoing HCV RNA testing and initiating treatment, and demographic and clinical predictors., Results: By Dec. 31, 2018, 4962 people tested positive for HCV antibody. Of those testing positive, 4118 (83.0%) were tested for HCV RNA, with 2480 (60.2%) testing positive. Genotyping was completed in 2374 (95.7%) of those who tested positive for HCV RNA, with 1002 (42.2%) initiating treatment. Nearly 80% ( n = 801, 79.9%) of treated people achieved SVR, with 34 (4.2%) experiencing reinfection or relapse. Undergoing testing for HCV RNA was more likely among people in older age categories (within 1 yr of antibody test; adjusted hazard ratio [HR] 1.30, 95% confidence interval [CI] 1.19-1.41, among people aged 41-60 yr; adjusted HR 1.47, 95% CI 1.18-1.81, among people aged > 60 yr), those living in rural areas (adjusted HR 1.20, 95% CI 1.10-1.30), those with an index date after Dec. 31, 2013 (era of treatment with direct-acting antiviral regimens) (adjusted HR 1.99, 95% CI 1.85-2.15) and those with a record of substance use or addictive disorders (> 1 yr after antibody test; adjusted HR 1.38, 95% CI 1.18-1.60). Treatment initiation was more likely among people in older age categories at index date (adjusted HR 1.32, 95% CI 1.15-1.50, among people aged 41-60 yr; adjusted HR 2.62, 95% CI 1.80-3.82, among people aged > 60 yr) and those with a later diagnosis year (adjusted HR 2.71, 95% CI 2.29-3.22)., Interpretation: In comparison with HCV testing and diagnosis, a substantial gap in treatment initiation remains among Status First Nations populations in Ontario. Elimination efforts that prioritize linkage to care and integration with harm reduction and substance use services are needed to close gaps in HCV care among First Nations populations in Ontario., Competing Interests: Competing interests: William Wong and Murray Krahn have received research support from the Canadian Liver Foundation. Beate Sander reports travel support from the Canadian Network on Hepatitis C. Jordan Feld has received research support or consulting fees from Abbvie, Enanta and Gilead, and is past president of the Canadian Association for the Study of the Liver., (© 2023 CMA Impact Inc. or its licensors.)

Background: Direct-acting antiviral agents (DAAs) have transformed chronic hepatitis C (CHC) treatment. Continued affordable access to DAAs requires updated cost-effectiveness analyses (CEA). Utility is a preference-based measure of health-related quality of life (HRQoL) used in CEA. This study evaluated the impact of DAAs on utilities for patients with CHC in two clinical settings., Methods: This prospective longitudinal study included patients aged ≥18 years, diagnosed with CHC and scheduled to begin DAA treatment, from two tertiary care hospital clinics and four community clinics in Toronto, Calgary, and Montreal. Patients completed two utility instruments (EQ-5D-5L and Health Utilities Index 2/3 (HUI2/3)) before treatment, 6 weeks after treatment initiation, and 12 weeks and 1 year after treatment completion. We measured utilities for all patients, and for hospital-based and community-based groups., Results: Between 2017 and 2020, 209 patients (126 hospital-based, 83 community-based; average age 53 years; 65% male) were recruited, and 143 completed the 1-year post-treatment assessment. Pre-treatment, utilities were (mean ± standard deviation) 0.77 ± 0.21 (EQ-5D-5L), 0.69 ± 0.24 (HUI2) and 0.58 ± 0.34 (HUI3). The mean changes at 1-year post-treatment were 0.035, 0.038 and 0.071, respectively. While utilities for hospital-based patients steadily improved, utilities for the community-based cohort improved between baseline and 12-weeks post-treatment, but decreased thereafter., Discussion: This study suggests that utilities improve after DAA treatment in patients with CHC in a variety of settings. However, community-based patients may face challenges related to comorbid health and social conditions that are not meaningfully addressed by treatment. Our study is essential for valuing health outcomes in CHC-related CEA., (© 2023 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.)

BACKGROUND: Although chronic hepatitis C (CHC) disproportionately affects marginalized individuals, most health utility studies are conducted in hospital settings which are difficult for marginalized patients to access. We compared health utilities in CHC patients receiving care at hospital-based clinics and socio-economically marginalized CHC patients receiving care through a community-based program. METHODS: We recruited CHC patients from hospital-based clinics at the University Health Network and community-based sites of the Toronto Community Hep C Program, which provides treatment, support, and education to patients who have difficulty accessing mainstream health care. We elicited utilities using six standardized instruments (EuroQol-5D-3L [EQ-5D], Health Utilities Index Mark 2/Mark 3 [HUI2/HUI3], Short Form-6D [SF-6D], time trade-off [TTO], and Visual Analogue Scale [VAS]). Multivariable regression analysis was performed to examine factors associated with differences in health utility. RESULTS: Compared with patients recruited from the hospital setting ( n = 190), patients recruited from the community setting ( n = 101) had higher unemployment (87% versus 67%), history of injection drug use (88% versus 42%), and history of mental health issue(s) (79% versus 46%). Unadjusted health utilities were lower in community than hospital patients (e.g., EQ-5D: 0.722 [SD 0.209] versus 0.806 [SD 0.195]). Unemployment and a history of mental health issue(s) were significant predictors of low health utility. CONCLUSIONS: Socio-economically marginalized CHC patients have lower health utilities than patients typically represented in the CHC utility literature. Their utilities should be incorporated into future cost-utility analyses to better represent the population living with CHC in health policy decisions., (© Canadian Association for the Study of the Liver, 2023.)

BACKGROUND: Administrative health data provide a rich and powerful tool for health services research. Partnership between researchers and the Ontario First Nations HIV/AIDS Education Circle (OFNHAEC) allowed for comprehensive analyses of the health and economic impacts of hepatitis C virus (HCV) infection in First Nations populations across Ontario, using administrative data. Examples of meaningful involvement of First Nations partners in research using secondary data sources demonstrate how community-based participatory research principles can be adapted to empower First Nations stakeholders and decision-makers. The aim of this review is to summarize and reflect on lessons learned in producing meaningful and actionable First Nations HCV research using health administrative data, from the perspective of health services researchers who collaborated for the first time with First Nations partners. METHODS: We discuss how our relationship with OFNHAEC formed and how engagement contextualized findings and provided opportunities for fostering trust and mutual capacity building. Methods included adherence to data governance principles, agreements outlining ethical conduct, and establishing commitment between partners. RESULTS: Engagement with OFNHAEC enhanced cultural understandings in study conception, design, and analysis, and enabled meaningful lessons for both parties through contextualizing findings together. Partnership ensured attention to factors, such as strength-based approaches and limitations of administrative data in their representation of First Nations peoples, that are not considered in standard HCV health services research using administrative health data. CONCLUSIONS: Collaboration throughout the HCV research provided first-hand experience of the relevance, representation, and importance of incorporating First Nations perspectives in health services research using administrative data., (© Canadian Association for the Study of the Liver, 2023.)

Background: The efficacy of a single dose of pegylated interferon lambda in preventing clinical events among outpatients with acute symptomatic coronavirus disease 2019 (Covid-19) is unclear., Methods: We conducted a randomized, controlled, adaptive platform trial involving predominantly vaccinated adults with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection in Brazil and Canada. Outpatients who presented with an acute clinical condition consistent with Covid-19 within 7 days after the onset of symptoms received either pegylated interferon lambda (single subcutaneous injection, 180 μg) or placebo (single injection or oral). The primary composite outcome was hospitalization (or transfer to a tertiary hospital) or an emergency department visit (observation for >6 hours) due to Covid-19 within 28 days after randomization., Results: A total of 933 patients were assigned to receive pegylated interferon lambda (2 were subsequently excluded owing to protocol deviations) and 1018 were assigned to receive placebo. Overall, 83% of the patients had been vaccinated, and during the trial, multiple SARS-CoV-2 variants had emerged. A total of 25 of 931 patients (2.7%) in the interferon group had a primary-outcome event, as compared with 57 of 1018 (5.6%) in the placebo group, a difference of 51% (relative risk, 0.49; 95% Bayesian credible interval, 0.30 to 0.76; posterior probability of superiority to placebo, >99.9%). Results were generally consistent in analyses of secondary outcomes, including time to hospitalization for Covid-19 (hazard ratio, 0.57; 95% Bayesian credible interval, 0.33 to 0.95) and Covid-19-related hospitalization or death (hazard ratio, 0.59; 95% Bayesian credible interval, 0.35 to 0.97). The effects were consistent across dominant variants and independent of vaccination status. Among patients with a high viral load at baseline, those who received pegylated interferon lambda had lower viral loads by day 7 than those who received placebo. The incidence of adverse events was similar in the two groups., Conclusions: Among predominantly vaccinated outpatients with Covid-19, the incidence of hospitalization or an emergency department visit (observation for >6 hours) was significantly lower among those who received a single dose of pegylated interferon lambda than among those who received placebo. (Funded by FastGrants and others; TOGETHER ClinicalTrials.gov number, NCT04727424.)., (Copyright © 2023 Massachusetts Medical Society.)

Background: The World Health Organization recommends universal birth dose vaccination for hepatitis B virus (HBV), yet only 3 provinces and territories in Canada provide birth dose vaccination, and Canadian-born children in Ontario are acquiring HBV before adolescent vaccination. We sought to determine whether birth and/or infant HBV vaccination is cost-effective., Methods: We used a dynamic HBV model that incorporates population by year, disease stage, sex and the influence of immigration to quantify the disease and economic burden of chronic HBV infection in Ontario from 2020 to 2050. We compared 4 vaccination scenarios, which included a birth dose vaccine and variations of the 2 subsequent doses (either alone or as a part of the hexavalent vaccine) and a hexavalent-only strategy in infancy with the current adolescent vaccination strategy. Our costing estimates were based on values from 2020., Results: All 4 infant vaccination approaches prevented an additional 550-560 acute and 160 chronic pediatric HBV infections from 2020 to 2050 compared with adolescent vaccination. Whereas birth dose could be cost-effective, incorporating vaccination into a hexavalent vaccine was cost saving. By 2050, the hexavalent approach led to $428 000 in cost savings per disability-adjusted life years averted., Interpretation: At the current prevalence in Ontario, a switch to birth dose or infant dose will be cost-effective or even cost saving. Introducing any form of infant HBV immunization in Ontario will prevent acute and chronic pediatric HBV infections., Competing Interests: Competing interests: Harry Janssen has received consultant fees and honoraria from Aligos, Antios, Arbutus, Eiger, Gilead Sciences, GSK, Janssen, Merck, Roche, VBI Vaccines, Vir Biotechnology and Viroclinics. Jordan Feld has received consultant fees from AbbVie, Antios, Arbutus, Eiger, Enanta, BlueJay, GSK, Janssen and Roche. Mia Biondi has received honoraria from Gilead and AbbVie. Hemant Shah has received consultant fees and honoraria from AbbVie, Gilead, Intercept and Lupin SCOPE. He has also received travel support and is a member of the advisory boards of AbbVie, Gilead, Intercept and Lupin. Homie Razavi was a member of the advisory boards of Gilead, AbbVie, Abbott, Merck, Janssen, Roche and VBI Vaccines. He is also a member of the board of directors of the Center for Disease Analysis Foundation. No other competing interests were declared., (© 2022 CMA Impact Inc. or its licensors.)

Accumulation of activated immune cells results in nonspecific hepatocyte killing in chronic hepatitis B (CHB), leading to fibrosis and cirrhosis. This study aims to understand the underlying mechanisms in humans and to define whether these are driven by widespread activation or a subpopulation of immune cells. We enrolled CHB patients with active liver damage to receive antiviral therapy and performed longitudinal liver sampling using fine-needle aspiration to investigate mechanisms of CHB pathogenesis in the human liver. Single-cell sequencing of total liver cells revealed a distinct liver-resident, polyclonal CD8+ T cell population that was enriched at baseline and displayed a highly activated immune signature during liver damage. Cytokine combinations, identified by in silico prediction of ligand-receptor interaction, induced the activated phenotype in healthy liver CD8+ T cells, resulting in nonspecific Fas ligand-mediated killing of target cells. These results define a CD8+ T cell population in the human liver that can drive pathogenesis and a key pathway involved in their function in CHB patients.

Individuals who spontaneously clear hepatitis C virus (HCV) infection have demonstrated evidence of partial protective immunity, whereas treatment-induced clearance provides little or no protection against reinfection. We aimed to investigate whether treatment of acute HCV infection with direct-acting antivirals (DAA) prevents establishment of, or reverses, T-cell exhaustion, leading to a virus-specific T-cell immune profile more similar to that seen in spontaneous clearance. The magnitude and breadth of HCV-specific T-cell responses before and after DAA or interferon-based therapy in acute or chronic HCV were compared to those of participants with spontaneous clearance of infection, using Enzyme-linked Immunospot (ELISPOT). PBMCs were available for 55 patients comprising 4 groups: spontaneous clearance (n = 17), acute interferon (n = 14), acute DAA (n = 13) and chronic DAA (n = 11). After controlling for sex, the magnitude of post-treatment HCV-specific responses after acute DAA treatment was greater than after chronic DAA or acute IFN treatment and similar to those found in spontaneous clearers. However, spontaneous clearers responded to more HCV peptide pools indicating greater breadth of response. In conclusion, early treatment with DAAs may prevent or reverse some degree of immune exhaustion and result in stronger HCV-specific responses post-treatment. However, individuals with spontaneous clearance had broader HCV-specific responses., (© 2022 John Wiley & Sons Ltd.)

In 2016, the World Health Organization released a plan to eliminate viral hepatitis as a public health threat by 2030. For Canada to achieve the recommended decreases in HBV- and HCV-related new diagnoses and deaths, an increase in services is urgently required. Identifying those at risk of, or who have acquired HBV and HCV, remains a challenge, especially with the emergence of new priority populations such as pregnant persons and children. Importantly, prenatal, and pediatric care are times when individuals are often already engaged with the healthcare system, leading to the potential for opportunistic or co-localized care and interventions. At present, Canada may not be maximizing all available virologic tools that could lead to increases in prevention, identification, improved management, or even cure. Here, we describe the continuum of care that includes preconception, prenatal, postpartum, and pediatric stages; and identify current global and Canadian recommendations, findings, and opportunities for improvement.

Background: Chronic hepatitis B (CHB) remains a major cause of morbidity and mortality. EDP-514 is a potent core inhibitor of hepatitis B virus (HBV) that reduces viral load reduction in HBV-infected chimeric mice. This first-in-human study evaluated the safety, tolerability, and pharmacokinetics (PK) of EDP-514 in healthy subjects and antiviral activity in patients with CHB., Methods: In Part 1, 82 subjects received placebo or EDP-514 in fed or fasted state as single ascending doses of 50-800 mg and multiple ascending doses of 200-800 mg for 14 days. In Part 2, 24 HBV DNA-suppressed, nucleos(t)ide (NUC)-treated (i.e., NUC-suppressed) CHB patients received EDP-514 200-800 mg or placebo for 28 days., Results: EDP-514 was well tolerated in healthy subjects and CHB patients with most adverse events of mild intensity. In Part 1, EDP-514 exposure increased in an approximately dose proportional manner up to 600 mg after single doses and up to 400 mg after 14-day dosing. In Part 2, EDP-514 exposure increased linearly with dose on Day 1 and Day 28, with some accumulation for Day 28 and median trough concentrations (C trough ) approximately 20-fold above the protein-adjusted 50% effective concentration (EC 50 ) for the dose range. Mean change in HBV RNA from baseline to Day 28 was -2.03, -1.67, -1.87, and -0.58 log U/mL in the 200 mg, 400 mg, 800 mg, and placebo CHB groups, respectively., Conclusions: EDP-514 was well tolerated, had a PK profile supporting once daily dosing, and reduced HBV RNA levels in NUC-suppressed CHB patients.

Chronic hepatitis C virus (HCV) infection has the greatest health impact in patients with advanced liver disease. The direct-acting antiviral (DAA) regimen glecaprevir/pibrentasvir (G/P) is approved for treatment of HCV-infected patients without cirrhosis and with compensated cirrhosis. However, events of liver decompensation/failure have been reported in patients treated with protease-inhibitor-containing DAA regimens, often in patients with advanced liver disease. This study examines the safety of on-label G/P treatment in patients with compensated cirrhosis (F4 at baseline) with markers of advanced liver disease. Patients with cirrhosis were categorized into 4 subgroups, based on different noninvasive markers of advanced liver disease identified using laboratory measures: platelet count < or ≥ 100 × 10 9 /L, and Child-Pugh score 5 or 6. Separate analyses were performed using pooled data from clinical trials and from real-world post-marketing observational studies. G/P was well tolerated in patients with platelet count ≥100 × 10 9 /L (n = 800), platelet count <100 × 10 9 /L (n = 215), a Child-Pugh score of 5 (n = 915) and a Child-Pugh score of 6 (n = 95). In the clinical trial and real-world cohorts two patients and no patients experienced a serious adverse event (AE) possibly related to study drug, respectively; three patients and no patients experienced an AE of special interest for hepatic decompensation and hepatic failure. This analysis reaffirms G/P's safety profile in indicated patients with compensated cirrhosis, including those with markers of more advanced liver disease. Increasing the number of patients treated with short-duration G/P therapy may contribute to meeting HCV elimination targets., (© 2022 The Authors. Journal of Viral Hepatitis published by John Wiley & Sons Ltd.)