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Background and Aims: The prevalence of hepatitis delta virus (HDV) infection among persons living with hepatitis B virus (HBV) and its impact on liver-related complications in West Africa are ill-defined. Wetested a large urban HBV cohort in Senegal for the presence of HDV/HBV co-infection and evaluated its association with liver fibrosis., Methods: We included persons with positive hepatitis B surface antigen (HBsAg) enrolled in the SEN-B cohort since 2019. Anti-HDV antibodies (HDVAb) were tested using the Anti-HD Diasorin LiaisonXL test, HDV RNA was measured with RT-qPCR and genotyping was determined through sequencing. We used multivariable logistic regression to evaluate the association between HDVAb positivity and liver fibrosis, defined as a liver stiffness measurement > 7.0 kPa., Results: We analysed 914 individuals with a median age of 32 years (interquartile range [IQR] 26-41), of whom 487 (53.3%) were men and 117 (12.8%) had HIV co-infection. Thirteen participants (1.4%, 95% CI 0.8-2.4) had a positive HDVAb test, of whom 8/13 (61.5%) showed detectable HDV RNA. HDV genotype 5 was found in 75.0% of cases. In multivariable analyses, HDVAb positivity (aOR 11.7, 95% CI 3.1-45.7), male sex (aOR 5.4, 95% CI 3.1-10.3), ALT > 40 IU/L (aOR 4.4, 95% CI 2.4-8.2) and HBeAg positivity (aOR 4.6, 95% CI 1.8-11.9) were independently associated with liver fibrosis., Conclusion: The prevalence of HDV infection was low in persons living with HBV in Dakar, but those affected had a very high risk of presenting with liver cirrhosis. Efforts to improve HDV screening and management are urgently needed in Senegal., (© 2025 The Author(s). Liver International published by John Wiley & Sons Ltd.)

Background and Aims: The impact of bulevirtide in patients awaiting liver transplantation (LT) for decompensated liver disease and/or hepatocellular carcinoma (HCC) is unclear. We assessed clinical, virological, and biochemical responses to bulevirtide in patients with chronic hepatitis delta virus (HDV) awaiting LT and compared outcomes with a cohort of similar untreated patients., Methods: Consecutive HDV-infected patients waiting for LT since bulevirtide approval were included. Patients receiving 2 mg of bulevirtide daily had clinical, biological, and virological data collected at baseline, Week 24, Week 48, at LT, and post-LT. Patients not receiving bulevirtide had data collected at baseline, LT, and post-LT for comparison., Results: Forty-one patients from nine LT centers were included. In the bulevirtide group (20 patients; mean age 52.8 ± 9.98 years; 75% male), 65%, 10% and 25% were Child-Pugh A, B and C, respectively. Fifteen completed 48 weeks of therapy. At 48 weeks, median HDV RNA decreased by 2.56 log IU/mL (p = 0.004). Virological and biochemical responses were obtained in 73.3% and 66.6% of patients. Twelve patients (60%) underwent LT. No serious adverse events occurred. Bulevirtide improved liver function, enabling one (7.1%) HCC patient to undergo chemoembolization while on the WL and leading to delisting of three (15%) other patients. In untreated patients (mean age 42.9 ± 7.9 years; 76.2% Child-Pugh C), none were delisted. Three-month transplant-free survival was 76.9% in the bulevirtide group versus 36.7% (p = 0.007) in the control group., Conclusions: Bulevirtide demonstrates safety and efficacy in HDV-infected patients listed on the LT waiting list and may potentially improve pre-transplant outcomes., (© 2025 The Author(s). Liver International published by John Wiley & Sons Ltd.)

Introduction: Hepatitis D virus (HDV) infection remains a significant global health challenge due to its severity and high risk of progression to cirrhosis and hepatocellular carcinoma (HCC). Bulevirtide, a novel HDV entry inhibitor, has shown promise in managing chronic hepatitis D by blocking viral entry into hepatocytes. This study evaluated the efficacy and safety of bulevirtide in reducing HDV RNA levels and improving liver function in a real-life cohort of Italian patients with HDV infection., Methods: This multicenter prospective trial enrolled 108 consecutive patients with chronic HDV infection, from June 2023 to June 2024, who received 2 mg/day of bulevirtide in combination with a nucleoside/nucleotide analogue for hepatitis B virus (HBV) infection. Patients with any stage of liver fibrosis or compensated cirrhosis were included. Data collected included demographic and clinical characteristics, liver function tests, HDV RNA levels, and adverse events at baseline and 6 months., Results: The virological response was achieved in 54.6% of patients ( n = 59), with 36 demonstrating undetectable HDV RNA levels. Among responders, ALT levels decreased significantly from 67.0 U/mL [IQR 44.0-116.3] to 31.5 U/mL [IQR 24.0-36.5, p = 0.001], and AST levels from 66.0 U/mL [IQR 46.5-91.0] to 32.5 U/mL [IQR 28.0-38.0, p = 0.021]. Median HDV RNA dropped from 29,800 IU/mL [IQR 3100-375,000] to 0 IU/mL [IQR 0-291, p < 0.001]. No significant predictors of response emerged. Mild adverse events, including pruritus (5.6%) and injection-site reactions (1.9%) and flu-like syndrome (0.9) were reported, with no treatment discontinuation., Conclusions: Bulevirtide effectively reduces HDV RNA levels and improves liver function with a favorable safety profile, offering a promising therapeutic option for chronic hepatitis D. Further large-scale studies are needed to confirm these findings and explore long-term outcomes.

In the last few years there have been innovations in HDV therapy which have brought new excitement in the scientific community also considering the few therapeutic opportunities. Recently, new molecular targets have been identified, both in monotherapy and in combination with peginterferon alpha (PegIFNα). Evaluating this review of the literature of the last ten years, HDV-related chronic hepatitis seems to have become a potentially curable disease, a statement that was unthinkable a few years ago. There are old and new weapons at our disposal. The old weapons are PegIFNα and recently PegIFN-lambda (PegIFNλ). PegIFNα, for which there are more data, appears to be an excellent combination regimen, if not contraindicated, both for Bulevirtide (BLV), data supported by important clinical trials and real-world studies, and probably for lonarfanib, although in the latter case the results are not yet definitive as the studies are fewer. However, data on long-term follow-up are needed., Competing Interests: The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2025 Pisaturo, Russo, Grimaldi, Martini and Coppola.)

BackgroundSince 2009, European guidelines recommend individuals with hepatitis B virus (HBV) and HIV be tested for hepatitis D virus (HDV).AimTo analyse HDV testing in individuals with HBV/HIV during routine practice in the Netherlands.MethodsWe assessed data from the ATHENA cohort of people with HIV who were ever HBV surface antigen-positive, aged ≥ 18 years and attended one of 24 HIV treatment centres in the Netherlands during 2000-22. Using longitudinal analysis, we estimated the percentage of individuals ever tested for HDV (antibody or RNA test) over time. In cross-sectional analysis, determinants for ever being tested by end of follow-up were assessed using relative risk regression.ResultsWe identified 1,715 individuals with HBV/HIV; 1,460 (85.1%) and 255 (14.9%) were male and female at birth, respectively (median age: 52 years; IQR: 42-59). Only 249 (14.5%) had an HDV test. The percentage tested increased from 5.0% (95% CI: 3.4-7.3) in 2000 to 17.0% (95% CI: 14.9-19.3) in 2022. In 2022, 16.2% (95% CI: 13.7-19.1) of men who have sex with men, 25.0% (95% CI: 9.7-50.9) of persons who inject(ed) drugs and 18.1% (95% CI: 14.6-22.3) of heterosexual/others were tested. In multivariable analysis, ever having an HDV test was associated with detectable HBV DNA viral load (p < 0.001), ever presenting with elevated alanine aminotransferase (ALT) levels (p = 0.023), advanced fibrosis/cirrhosis (p = 0.001) and being overweight/obese (p = 0.043).ConclusionsHDV testing coverage in the Netherlands is low for individuals with HBV/HIV. Although testing was more common in those with advanced liver disease, a considerable proportion at risk of HDV still need testing.

Background and Aim: Bulevirtide (BLV) leads to beneficial virologic and biochemical responses when given alone to treat hepatitis delta virus (HDV) infection, which causes the most severe form of chronic viral hepatitis. We evaluated 48 weeks of BLV monotherapy, BLV + tenofovir disoproxil fumarate (TDF) and BLV + pegylated interferon alfa-2a (Peg-IFNα-2a), with 24-week follow-up., Methods: Ninety patients were enrolled into six arms of 15 each (A-F); 60 patients were included in the main randomisation (arms A-D), and 30 patients (arms E-F) were randomised to the extension phase: (A) Peg-IFNα-2a 180 μg once weekly (QW); (B) BLV 2 mg once daily (QD) + Peg-IFNα-2a 180 μg QW; (C) BLV 5 mg QD + Peg-IFNα-2a 180 μg QW; (D) BLV 2 mg QD; (E) BLV 10 mg QD + Peg-IFNα-2a 180 μg QW and (F) BLV 10 mg (5 mg twice daily) + TDF QD. The primary endpoint was undetectable HDV RNA at week (W)72., Results: At W72, 53%, 27%, 7%, 7% and 33% of patients achieved undetectable HDV RNA in arms B, C, D, E and F, respectively, versus 0% in arm A. More arm B versus A patients had a > 1 log 10 IU/mL decline in or loss of hepatitis B surface antigen (HBsAg) at W72 (p = 0.017), including four patients with loss of HBsAg. Bile acid elevations were dose-dependent and reversible following the completion of BLV treatment., Conclusions: BLV combined with Peg-IFNα-2a was well tolerated and resulted in high rates of HDV RNA undetectability off-treatment., Trial Registration: NCT02888106., (© 2025 The Author(s). Liver International published by John Wiley & Sons Ltd.)

Hepatitis delta virus (HDV) infection has an aggressive disease course and is the most difficult to treat of the human hepatitis viruses. In Denmark, as in many countries, the national prevalence of HDV has not been established. Based on diagnoses and laboratory test results in national healthcare registries, we estimated that the prevalence of current HDV infection amongst patients with chronic hepatitis B was 3.1% and the general population prevalence approximately 4 in 100,000.

Hepatitis B virus (HBV)-hepatitis delta virus (HDV) coinfection is the most severe form of chronic viral hepatitis, but the factors that determine disease progression and severity are incompletely characterised. This long-term follow-up study aims to identify risk factors for severe liver-related outcomes. In this multicentre national cohort study, data from admission until the last visit between 2001 and 2023 was retrospectively collected from 162 HBV-HDV coinfected patients. The inclusion criteria were HBsAg or HBV DNA positivity, anti-HDV or HDV RNA positivity, and at least one follow-up visit. The median follow-up was 6.2 years (IQR 3.3-10.2). At baseline, 68/152 (44.7%) patients were diagnosed with advanced liver fibrosis. Forty patients (24.7%) had at least one severe liver-related outcome during follow-up. HDV viremia was detectable in 92 patients (64.3%) at last evaluation and was more frequently detectable in patients of European origin (p < 0.001). HDV RNA-positive patients had a 4.7-fold higher risk for severe liver-related outcomes (p < 0.001) and were more frequently diagnosed with advanced fibrosis at baseline (p = 0.007) compared to HDV RNA-negative patients. Multivariate analyses identified HDV RNA positivity, as well as several markers for liver disease severity, such as INR, platelet count, and advanced fibrosis at baseline, and age at admission as independent risk factors for severe liver-related outcomes. In conclusion, almost one in four HBV-HDV coinfected patients developed a severe liver-related outcome during follow-up. Several markers for liver disease severity and HDV RNA positivity were the strongest predictors for outcomes., (© 2025 The Author(s). Journal of Viral Hepatitis published by John Wiley & Sons Ltd.)

Coinfection with HBV and HDV results in hepatitis D, the most severe form of chronic viral hepatitis, frequently leading to liver decompensation and HCC. Pegylated interferon alpha, the only treatment option for chronic hepatitis D for many years, has limited efficacy. New treatments are in advanced clinical development, with one recent approval. Diagnosis and antiviral treatment response monitoring are based on detection and quantification of HDV RNA. However, the development of reliable HDV RNA assays is challenged by viral heterogeneity (at least 8 different genotypes and several subgenotypes), intrahost viral diversity, rapid viral evolution, and distinct secondary structure features of HDV RNA. Different RNA extraction methodologies, primer/probe design for nucleic acid tests, lack of automation, and overall dearth of standardization across testing laboratories contribute to substantial variability in performance characteristics of research-based and commercial HDV RNA assays. A World Health Organization (WHO) standard for HDV RNA, available for about 10 years, has been used by many laboratories to determine the limit of detection of their assays and facilitates comparisons of RNA levels across study centers. Here we review challenges for robust pan genotype HDV RNA quantification, discuss particular clinical needs and the importance of reliable HDV RNA quantification in the context of drug development and patient monitoring. We summarize distinct technical features and performance characteristics of available HDV RNA assays. Finally, we provide considerations for the use of HDV RNA assays in the context of drug development and patient monitoring., (Copyright © 2023 The Author(s). Published by Wolters Kluwer Health, Inc.)

Background and Aims: Chronic hepatitis D virus (HDV) infection can cause severe liver disease. With new treatment options available, it is important to identify patients at risk for liver-related complications. We aimed to investigate kinetics and predictive values of novel virological and immunological markers in the natural course of chronic HDV infection., Methods: HBcrAg, HBV RNA and quantitative anti-HBc were analysed in samples from HDV-infected patients at three consecutive time points. Results were linked to clinical outcome by univariable and multivariable analyses. Primary endpoint was the composite endpoint of any liver-related event., Results: Samples from 190 individual patients were analysed with a median clinical follow-up time of 2.69 (IQR 1.13-6.51) years. The majority of patients had cirrhosis (98/190, 52%), and the primary endpoint occurred in 33% (62/190). In univariable analysis, age, cirrhosis, lower quantitative anti-HBc, higher ratio of HBcrAg/anti-HBc and detectable HDV RNA were associated with the primary endpoint. In multivariable analysis, only the presence of liver cirrhosis (HR 7.74, p < 0.001) and age (1.06, p < 0.001) remained independently associated with the primary endpoint. Kinetics of virological parameters during follow-up were similar between the groups. Quantitative anti-HBc was significantly lower in patients with liver cirrhosis (687 (IQR 188-3388) IU/ml vs. 309 (IQR 82-924) IU/ml, p < 0.0004), and lower levels were independently associated with the development of the primary endpoint (HR 1.0, p = 0.014)., Conclusion: In chronic HDV infection, neither baseline values nor kinetics of HBV RNA, HBcrAg and anti-HBc were independently associated with clinical outcome, while stage of liver disease and age were predictors of liver-related events., (© 2025 The Author(s). Liver International published by John Wiley & Sons Ltd.)

Background: Despite European guidelines recommending anti-hepatitis D virus (HDV) screening for all hepatitis B surface antigen (HBsAg)-positive cases, screening rates remain insufficient., Aims: We analysed anti-HDV screening rates in primary care and implemented prospective HDV screening in HBsAg-positive cases identified in the preventive medical examination from the age of 35 ("Check-Up 35+")., Methods: From 2012 to 2021, we reviewed anti-HDV and HDV RNA test rates in HBsAg-positive patients at 11 sites of a large German laboratory group. From 2022 to 2023, we prospectively screened HBsAg-positive samples from the "Check-Up 35+" for anti-HDV. Anti-HDV positive patients were then contacted again for HDV RNA testing., Results: Retrospectively, 2792/13,905 (20%) HBsAg-positive cases were tested for anti-HDV, with 142/2792 (5.1%) being positive. HDV RNA was tested in 57/142 (40%) anti-HDV-positive cases, with 26/57 (46%) being positive. In the prospective screening, 1159/225,901 (0.51%) individuals were HBsAg-positive. Of these, 700 (60%) were tested for anti-HDV, with 18/700 (2.6%) positive test results. 4/18 (22%) were successfully contacted again for HDV RNA analysis, with one case testing positive. Neither the HBsAg nor the anti-HDV positive result was known prior to screening in these cases. Anti-HDV testing could not be performed in 459/1159 (40%) HBsAg-positive cases, primarily due to insufficient blood sample volume (310/459 cases, 68%), with others missed due to logistical errors., Conclusions: Retrospective data show insufficient anti-HDV screening in clinical routine. The prospective anti-HDV screening provides a blueprint for using existing hepatitis B virus screening programms for population-based HDV double reflex testing, provided that adequate logistical prerequisites are established., Trial Registration: German Clinical Trial Register: DRKS00029180., (© 2024 The Author(s). Alimentary Pharmacology & Therapeutics published by John Wiley & Sons Ltd.)

Hepatitis D virus (HDV) significantly influences the progression of liver diseases. Through clinical observations and database analyses, it has been established that patients coinfected with HDV and hepatitis B virus (HBV) experience accelerated progression toward cirrhosis, hepatocellular carcinoma (HCC), and liver failure compared to those infected solely with HBV. A higher viral load correlates with increased replicative activity, enhanced infectivity, and more severe disease manifestations. In this study, we use HDV gRNA-sensitive semiconducting polymer dots (Pdots) as the nanoprobes for the quantitative analysis of HDV copy number variations. The surface of the Pdots is engineered with a clamp design that includes a pair of reporter sequences, protection sequences, and capture sequences tailored to the conserved sequence length of the HDV genome. The capture sequence, comprising leading and trailing chains, specifically binds to the gRNA of the target virus. The protection sequence shields the Pdots from external interference, while the reporter sequence detects the presence of target gRNA through the degradation of fluorescent dye Cy5.5dt. We demonstrate the effectiveness of this assay in a stably transfected cell line derived from HepG2-HDV cells and its translational application in clinical samples from patients. Additionally, this nanobiosensor can accurately detect gRNA at femtomolar (fM) levels, a sensitivity unachievable by previously reported methods. This novel virus quantification system offers significant potential for clinical and virological applications, enhancing screening, early diagnosis, and personalized treatment strategies.

Information on circulating HBV (sub-)genotype, variants, and hepatitis D virus (HDV) coinfection, which vary by geographical area, is crucial for the efficient control and management of HBV. We investigated the genomic characteristics of HBV (with a prevalence of 8.1%) and the prevalence of HDV in Nigeria. We utilised 777 HBV-positive samples and epidemiological data from the two-stage sampled population-based, nationally representative Nigeria HIV/AIDS Indicator and Impact Survey conducted in 2018. We assessed 732 HBV DNA-extracted samples with detectable viral loads (VLs) for (sub-)genotypes and variants by whole-genome pre-amplification, nested PCR of the s -and pol -gene, and BigDye Terminator sequencing. We conducted HDV serology. In total, 19 out of the 36 + 1 states in Nigeria had a high prevalence of HBV (≥8%), with the highest prevalence (10.4%) in the north-central geopolitical zone. Up to 33.2% (95% CI 30.0-36.6) of the participants had detectable VLs of ≥300 copies/mL. The predominant circulating HBV genotype was E with 98.4% (95% CI 97.1-99.1), followed by A with 1.6% (95% CI 0.9-2.9). Drug-resistant associated variants and immune escape variants were detected in 9.3% and 0.4%, respectively. The seroprevalence of HDV was 7.34% (95% CI 5.5-9.2). Nigeria has subtype E as the major genotype with many variants.

Computational RNA design was introduced in the 1990s by Vienna's RNAinverse, which is a simple inverse RNA folding solver. Further developments and contemporary RNA design techniques, in addition to improved efficiency, offer more precise control over the designed sequences. incaRNAfbinv (incaRNAtion with RNA fragment-based inverse) is one such extension that builds upon RNAinverse and includes coarse-graining manipulations. The idea is that an RNA secondary structure can be decomposed to fragments of RNA motifs, and that a significant number of known natural RNA motifs exhibit a remarkable preservation in particular locations in a variety of genomes. This is taken into consideration by the ability of the user to select motifs that are known to be functional for a precise design, whilst the algorithm is more adaptable on other motifs. The latest version, incaRNAfbinv 2.0, is a free-to-use web-server which deploys the above methodology of fragment-based design. Its control over the decomposed RNA secondary structure motifs includes, among other advanced features, the insertion of constraints in a flexible manner. The resultant RNA designed sequences are ranked by their proximity to classical RNA design. Features and capabilities of incaRNAfbinv 2.0 are hereby illustrated with an example taken from hepatitis delta virus (HDV). The web-server is demonstrated in assisting to locate a known RNA motif that is responsible for HDV-3 RNA editing in more HDV genotypes than thought of before. This shows that computational RNA design by using inverse RNA folding is also a valuable strategy for locating functional RNA motifs in genomic data, in addition to artificially designing synthetic RNAs., (© 2025. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)

Hepatitis D (HDV) is a severe infection with well-recognised clinical ramifications that remains relatively neglected and underdiagnosed; consequently, the epidemiology of HDV is poorly characterised, both in the United States and globally. In 2022, a pilot project involving eight healthcare institutions was undertaken to ascertain the prevalence of HDV in healthcare institutions with an HBV seropositivity of at least 1%, describe the characteristics of patients testing positive for HDV, and evaluate diagnostic and laboratory processes of HDV screening. From August 2022 to April 2024, a total of 106,693 patients were tested for HBsAg, of whom 65,341 (61.2%) were female and 40,863 (38.3%) were male, with a mean age of 47 years. The overall HBsAg positivity rate was 1.04% (n = 1112). Among the HBsAg+ samples, 645 (58.0%) underwent HDV Ab testing. The HDV Ab positivity rate was 0.81% (n = 9), with 2 cases of HDV RNA positivity (0.18%). The incomplete testing reflects several challenges associated with screening for both HBV and HDV. Further research is necessary to better understand the epidemiology and burden of HDV in the United States and considerations for implementation., (© 2024 The Author(s). Journal of Viral Hepatitis published by John Wiley & Sons Ltd.)

Background: Hepatitis D virus (HDV) RNA-positive cases with total anti-HDV antibodies nonreactive were documented. Moreover, HDV infection was observed in subjects with occult hepatitis B virus infection. The prevalence of HDV infection in Argentina is low; however, further research in different populations is needed., Objective: This study aimed to perform synchronous HDV detection in reactive hepatitis B virus patients treated in a public hospital in the province of Buenos Aires, Argentina, some of whom were coinfected with hepatitis C virus and/or HIV. A total of 189 hepatitis B virus-reactive serum samples with or without hepatitis C virus and/or HIV coinfection were synchronously analyzed for anti-HDV antibodies and HDV RNA., Results: HDV prevalence was 4.2% with HDV RNA found in 61 samples, most of which were nonreactive to anti-HDV antibodies and hepatitis B surface antigen. Genotype 1 was identified in all HDV sequences. Moreover, triple and quadruple infections were observed, showing a high frequency of HDV infection in hospitalized patients not following the recommended diagnostic algorithm., Conclusions: This study is evidence that the synchronous testing of anti-HDV antibodies and HDV RNA is necessary for the diagnosis of HDV infection in Argentina. Finally, further research is necessary to identify high-risk populations and improve prevention and control strategies for triple and quadruple infections and their potential consequences., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

Abstract: Hepatitis D virus (HDV) prevalence data and country-specific HDV guidelines are not widely available in the Gulf Cooperation Council (GCC) states. We developed consensus recommendations to guide healthcare professionals, policymakers, and researchers in improving HDV management and patient health outcomes in three GCC states: Kuwait, Saudi Arabia, and the United Arab Emirates. A consensus panel comprising hepatology experts (n = 6) from the three GCC societies was formed. The panel identified two broader areas related to clinical practice (screening and diagnosis, and treatment and management), addressed critical questions, and developed draft recommendations in February 2024. The strength of the final set of recommendations was subjected to consensus voting in March 2024. A majority was defined apriori with a two-thirds vote (67%). The paper outlines those recommendations alongside showcasing the current epidemiology of HDV in the GCC states, emphasizing the variability in prevalence, demographic patterns, and region-specific risk factors. It also highlights the current state of screening and diagnosis practices, identifying key obstacles, such as access to advanced screening protocols and diagnostic tools. Furthermore, HDV treatment landscape and preventative strategies are outlined, focusing on vaccination, public health initiatives, and the crucial role of public awareness and education. Ethical and sociocultural considerations are discussed, underscoring the importance of culturally sensitive healthcare practices. These recommendations present a comprehensive overview of the challenges and strategies for managing HDV in these states. Policy recommendations are provided to support HDV management, including standardizing care protocols and promoting public health measures., (Copyright © 2024 Saudi Journal of Gastroenterology.)

Hepatitis B virus (HBV) infection remains a major public health problem and, in associated co-infection with hepatitis delta virus (HDV), causes the most severe viral hepatitis and accelerated liver disease progression. As a defective satellite RNA virus, HDV can only propagate in the presence of HBV infection, which makes HBV DNA and HDV RNA the standard biomarkers for monitoring the virological response upon antiviral therapy, in co-infected patients. Although assays have been described to quantify these viral nucleic acids in circulation independently, a method for monitoring both viruses simultaneously is not available, thus hampering characterization of their complex dynamic interactions. Here, we describe the development of a dual fluorescence channel detection system for pan-genotypic, simultaneous quantification of HBV DNA and HDV RNA through a one-step quantitative PCR. The sensitivity for both HBV and HDV is about 10 copies per microliter without significant interference between these two detection targets. This assay provides reliable detection for HBV and HDV basic research in vitro and in human liver chimeric mice. Preclinical validation of this system on serum samples from patients on or off antiviral therapy also illustrates a promising application that is rapid and cost-effective in monitoring HBV and HDV viral loads simultaneously.

Background: Hepatocellular carcinoma (HCC) accounts for >90% of primary liver cancer cases, and chronic infections with hepatitis B virus (HBV) and hepatitis D virus (HDV) are major contributors., Methods: A comprehensive literature review was conducted using the MEDLINE (PubMed) database, focusing on studies related to HBV, HDV, and HCC., Results: HBV contributes to HCC through mechanisms like viral integration into the host genome, chronic inflammation, and immune modulation, leading to genomic instability and altered cell signaling. HDV exacerbates HBV-induced liver damage, accelerating fibrosis and cirrhosis, and significantly increasing HCC risk. Antiviral therapies and vaccinations have majorly reduced the burden of HBV-related HCC, but HDV remains challenging to treat due to limited therapeutic options. Emerging treatments like Bulevirtide showed promising results., Conclusion: This review highlights the critical impact of HBV and HDV co-infections on HCC development, emphasizing the need for more effective therapeutic strategies. While advances in antiviral therapies have reduced the incidence of HBV-related HCC, the high burden of HDV-related complications persists. Future research should focus on improving treatments for HDV and understanding its unique contribution to HCC pathogenesis., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Inc. All rights reserved.)

Introduction: Hepatitis B virus (HBV) affects 296 million people globally, causing 780 000 annual deaths. It has been estimated that 12-43 million individuals are co-infected with hepatitis D virus (HDV). In Spain, the prevalence of HBsAg in adults is 0.22%, with an anti-HDV prevalence of 7.7%, although not extensively documented since many HBsAg-positive cases are not tested for anti-HDV. The primary objective of this project is to optimise hepatitis D care by implementing a screening programme for anti-HDV in all HBsAg-positive individuals over a 1 year period in Catalonia. Secondary objectives include evaluating hepatitis D prevalence, establishing a digital registry for all anti-HDV positive cases, testing them for HDV-RNA in a centralised laboratory and offering linkage to care., Methods and Analysis: This prospective study will be performed in seven hospital centres in Catalonia, which attend to more than 95% of the adult population. Approximately, 9290 HBsAg-positive individuals are expected to be screened for anti-HDV in 1 year. All anti-HDV positive samples will be sent to a centralised laboratory for HDV-RNA quantification. All individuals testing positive for anti-HDV will be registered on an electronic platform and linked to care. The registry will collect data on demographics, infection stage, risk factors, disease awareness and previous diagnoses. No additional interventions will be conducted for those with adequate follow-up., Ethics and Dissemination: The Vall d'Hebron Hospital Ethics Committee (PR(AG)628/2023) and the Spanish Agency of Medicines and Medical Devices approved this study. These findings will be disseminated through peer-reviewed publications and conference presentations., Trial Registration Study: Grant number: IN-ES-980-7058., Competing Interests: Competing interests: MB has served as a speaker and advisory board member for Gilead, AbbVie, Roche, Arbutus and GSK. No competing interests were declared for AP, AR-S, GF, LC, AS-S, DPdC, SMB, MMOPM, DT, JA, MAL, JCQ., (© Author(s) (or their employer(s)) 2024. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background & Aims: Genetic polymorphisms in the sodium taurocholate cotransporting peptide (NTCP encoded by SLC10A1) have been described, but their role in untreated and treated patients with chronic hepatitis delta (CHD) remains unknown. Virological response (VR) to the NTCP inhibitor bulevirtide (BLV) was achieved at week 48 by >70% of patients with CHD, but nearly 15% experienced virological non-response (VNR) or partial response (PR). This study aimed to evaluate whether NTCP genetic polymorphisms affect baseline HDV RNA load and response to BLV in patients with CHD., Methods: BLV-untreated and -treated patients were enrolled in a retrospective cross-sectional and longitudinal study. Clinical and virological characteristics were collected at baseline and up to 96 weeks in the BLV-treated patients. NTCP genetic polymorphisms were identified by Sanger sequencing., Results: Of the six NTCP polymorphisms studied in 209 untreated patients with CHD, carriers of the rs17556915 TT/CC (n = 142) compared to CT (n = 67) genotype presented with higher median HDV RNA levels (5.39 vs. 4.75 log 10  IU/ml, p = 0.004). Of 209 patients receiving BLV monotherapy at 2 mg/day, 76 were evaluated at week 24 and 40 up to week 96. Higher mean baseline HDV RNA levels were confirmed in TT/CC (n = 43) compared to CT (n = 33) carriers (5.38 vs. 4.72 log 10  IU/ml, p = 0.010). Although 24-week VR was comparable between TT/CC and CT carriers (25/43 vs. 17/33, p = 0.565), the former group presented VNR more often than PR (9/11 vs. 9/23, p = 0.02) at week 24. 7/9 TT/CC genotype carriers remained VNR at week 48 of BLV treatment., Conclusions: The NTCP rs17556915 C>T genetic polymorphisms may influence baseline HDV RNA load both in BLV-untreated and -treated patients with CHD and may contribute to identifying patients with different early virological responses to BLV., Impact and Implications: Although several sodium taurocholate cotransporting polypeptide (NTCP) genetic polymorphisms have been described, no data are available on their potential role in modifying HDV RNA load or treatment response to bulevirtide (BLV) in patients with chronic hepatitis delta (CHD). In this study, we demonstrated that patients with CHD, either treated or untreated, carrying NTCP rs17556915 TT/CC, presented higher baseline HDV RNA levels compared to those with the CT genotype. Higher HDV RNA levels in TT/CC carriers compared to CT carriers were also confirmed in patients with CHD treated with BLV monotherapy up to 96 weeks. Furthermore, carriers of TT/CC, compared to CT genotype, more frequently showed viral non-response (VNR) than partial response (PR) at week 24 of BLV treatment, and 7/9 TT/CC genotype carriers remained VNR at week 48 of BLV treatment. This is the first study demonstrating a potential role of NTCP genetic polymorphisms in influencing HDV viral load and early virological response to BLV monotherapy. Since no direct HDV resistance to BLV has been described so far, if confirmed in larger studies, the genetic polymorphisms in NTCP may help identify patients with different patterns of early virological response to BLV., (Copyright © 2024 European Association for the Study of the Liver. Published by Elsevier B.V. All rights reserved.)

Hepatitis D virus (HDV), which occurs as a co-infection with the hepatitis B virus (HBV), is a significant public health burden. Currently, there is a scarcity of data regarding this co-infection in the developing countries. This study aims to address the clinical prevalence of HDV among HBV-infected patients in Sulaymaniyah Governorate, Iraq. This prospective cross-sectional study, conducted from May to November 2022, screened HBV DNA-positive patients visiting Sulaimani Teaching Hospital in Sulaymaniyah governorate, Iraq, for anti-HDV antibodies and HDV RNA. The study included 150 confirmed HBV DNA-positive patients. Of these, 54.7% were male. The mean age of the patients was 49.1 ± 10.1 (18-68). Serological assessment found that 23 (15.3%) of the patients had anti-HDV IgG antibodies, suggesting past or chronic HDV infection, while 16 (10.7%) tested positive for anti-HDV IgM, indicating recent/acute infection. Further molecular analysis confirmed HDV RNA in 15 (10%) of HBV patients, indicating real HDV prevalence. The prevalence of anti-HDV and HDV RNA did not significantly differ by age, gender, marital status, residency, medical, family or medical history (p > 0.05). In conclusion, this study demonstrated a relatively high HDV prevalence among HBV patients in Sulaymaniyah Governorate, Iraq, at 10%, which stresses the need for better screening, health strategies and focused research to combat its impact., (© 2024 John Wiley & Sons Ltd.)

Micro-RNAs (miRNAs) are involved in the modulation of viral replication and host immune antiviral response. Using next-generation sequencing, we investigated the miRNome profile of circulating extracellular vesicles in 20 patients with chronic hepatitis D virus (HDV) infection undergoing pegylated interferon alpha (Peg-IFNα) treatment. Circulating miRNAs' expression was analysed according to virologic response (i.e., HDV RNA clearance maintained at least 6 months after the end of therapy). Overall, 8 patients (40%) achieved a virologic response to Peg-IFNα treatment. At baseline, 14 miRNAs were differentially expressed between responders and non-responders; after 6 months of Peg-IFNα treatment, 7 miRNAs (miR-155-5p, miR-1246, miR-423-3p, miR-760, miR-744-5p, miR-1307-3p and miR-146a-5p) were consistently de-regulated. Among de-regulated miRNAs, miR-155-5p showed an inverse correlation with HDV RNA (at baseline: r s  = -0.39, p = 0.092; at 6 months: r s  = -0.53, p = 0.016) and hepatitis B surface antigen (HBsAg) (at baseline: r s  = -0.49, p = 0.028; at 6 months: r s -0.71, p < 0.001). At logistic regression analysis, both miR-155-5p (at baseline: OR = 4.52, p = 0.022; at 6 months: OR = 5.30, p = 0.029) and HDV RNA (at baseline: OR = 0.19, p = 0.022; at 6 months: OR = 0.38, p = 0.018) resulted significantly associated to virologic response. Considering that Peg-IFNα still has a relevant role in the treatment of patients with chronic hepatitis D infection, the assessment of EV miR-155-5p may represent an additional valuable tool for the management of HDV patients undergoing Peg-IFNα treatment., (© 2024 The Author(s). Journal of Viral Hepatitis published by John Wiley & Sons Ltd.)

Hepatitis D virus (HDV) is currently classified into 8 genotypes (1 to 8) and several subgenotypes, with distinct distribution worldwide. However, due to the scarcity of complete genome sequences in databases, this classification is constantly being updated and tends to be regularly revisited in upcoming years as more sequence data becomes available. Aiming to increase knowledge about the genetic variability of HDV, this study presents the full-length genomes of 11 HDV samples collected in Brazil in endemic and non-endemic regions, including the first complete genomes of the genotypes 5 and 8 obtained outside Africa. We also determined the co-infecting HBV genotypes to investigate their prevalence among the HDV-infected individuals throughout the country. Whole genome sequencing confirmed our previous findings based on a partial fragment of the HDV genome, in which HDV subgenoypes 3c (9/11; 81.8 %), 5b (1/11; 9.1 %) and one HDV-8 sequence (1/11; 9.1 %) were detected. As previously observed, HDV-8 formed a distinct branch apart from subgenotypes 8a and 8b, a monophyletic clade representing a novel HDV-8 subgenotype, designated as 8c. Among HDV-3 samples, the main co-infecting HBV genotype found was HBV-F (4/8; 50 %), reflecting the higher incidence of this native South American genotype in the endemic Amazon Basin. Both samples infected with HDV-5 and HDV-8 were coinfected with HBV genotype E, also a genotype with African origin. Our findings based on complete genome sequence of HDV corroborated our results based on a partial region of the HDV genome of a novel HDV-8 subgenotype and reinforced the need to use full-length genomes to properly subdivide genotypes with very low intragroup genetic variability, such as HDV-3. The provision of these complete genomes is expected to contribute to the enrichment of sequence databases for future molecular and evolutionary investigations of HDV., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Current US guidelines recommend risk-based testing for hepatitis delta virus (HDV) in persons with chronic hepatitis B (CHB). While there is debate as to whether a risk-based or universal testing approach is most effective, limited data exist on universal HDV testing programs in the United States. We performed a 1-year pilot study evaluating the outcomes of a universal HDV testing approach among US veterans with CHB. All consecutive adults with CHB receiving care at hepatology clinics at a single-centre Veterans Affairs Health System from 1 October 2022 to 30 September 2023 were prospectively tested for anti-HDV antibody (anti-HDV). Patients who were anti-HDV Ab-positive were subsequently tested for HDV RNA. Comparison of HDV testing between groups utilised chi-square testing. A total of 91 consecutive CHB patients (90.0% male, mean age 60.9 ± 14.1 years, 73.9% Asian, 26.1% non-Asia, 16.5% cirrhosis and 17.1% with active or past history of drug use) had anti-HDV ordered. Overall, 76.9% (n = 70) completed anti-HDV testing; 4.3% (n = 3) were positive. HDV RNA testing was ordered in all three patients; two patients completed HDV RNA testing and one had detectable HDV RNA. No significant differences in completion of anti-HDV testing was observed by age, sex, race/ethnicity, cirrhosis status or drug use history. Among a single-centre prospective cohort study piloting a universal HDV testing approach, one patient with viremic HDV was identified. Implementing true reflex testing of all CHB patients with anti-HDV, followed by automated HDV RNA testing for anti-HDV-positive patients would improve the HDV testing cascade and timely diagnosis of HDV., (© 2024 John Wiley & Sons Ltd.)

Objective: The objective of this study was to know the prevalence and clinical-epidemiological characteristics of patients with chronic infection due to hepatitis D virus (HDV)., Patients and Methods: A retrospective descriptive study was carried out on patients with HDV infection under follow-up in a hospital in 2023. All patients carrying HBsAg were tested for antibodies against HDV. HDV RNA detection was performed in all antibody-positive samples. The medical records were reviewed., Results: Of the 340 patients carrying HBsAg, 24 (7.1%) had anti-HDV antibodies, and 6 (25%) had detectable HDV RNA (chronic infection). The prevalence of chronic hepatitis in HBsAg carriers was 1.8%. All patients had a genotype 1 infection. Half of the patients were of African origin and 29.2% were Spanish. Of the 6 patients with chronic infection, 5 (83.3%) had cirrhosis and 2 (33.3%) had hepatocellular carcinoma. Half of the patients had some exacerbation of the disease during follow-up. Of the 18 patients without viremia, 2 (11.1%) presented cirrhosis (one recently diagnosed). The mean follow-up time of patients without viremia was 13.5 years., Conclusions: The prevalence of chronic HDV hepatitis in our area is low and in all cases it presents as an advanced disease, with exacerbations during follow-up. Patients without viremia have probably resolved the infection, as viremia was not detected in any moment., (Copyright © 2024 Sociedad Española de Enfermedades Infecciosas y Microbiología Clínica. Published by Elsevier España, S.L.U. All rights reserved.)

Background: The World Health Organization (WHO) recommends hepatitis D virus (HDV) screening among hepatitis B virus (HBV) infected individuals, with a focus on priority populations in resource-limited settings like Nigeria. HDV infection is a growing public health challenge, particularly among individuals with chronic hepatitis B virus (HBV) infection. HDV accelerates liver disease progression and significantly increases the risk of cirrhosis and hepatocellular carcinoma. Despite this, the epidemiology of HDV in Nigeria remains inadequately documented. This scoping review critically evaluates the prevalence, risk factors, and clinical outcomes of HDV co-infection among HBV patients in Nigeria., Method: We conducted a systematic review following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) 2020 guidelines. The review included observational cross-sectional studies published between 2009 and 2024. We focused on studies that used Immunoglobulin G (IgG) antibody testing or RNA-based diagnostics to assess HDV prevalence. We included PubMed, Google Scholar, and Dimensions databases due to their broad indexing and coverage of peer-reviewed articles and accessibility. We screened the studies for their relevance to HDV prevalence, risk factors, and clinical outcomes, while excluding those that only tested for IgM or HDV antigen. Eleven studies, with a combined sample size of 2308 participants, were included in the final analysis. We performed a narrative synthesis of the findings, considering geographic, gender, and age-based variations in HDV prevalence and clinical impact., Results: HDV prevalence among HBV-infected individuals in Nigeria ranged from 2.0% to 31.6%. The highest prevalence was reported in the Southwest (31.6%) among malaria patients, while lower rates were observed in the Southeast (2.8%). Prevalence was higher in males, particularly those aged 21-30 years in the Southwest and 31-40 years in other regions. RNA-based testing provided more accurate data on active viremia, with viremic HDV prevalence rates ranging from 3.2% to 16%. Triple infection with HIV/HBV/HDV was associated with significantly lower CD4+ cell counts and worse clinical outcomes, including elevated liver enzymes and rapid progression to liver cancer. Key risk factors for HDV co-infection included multiple sexual partners, sharing of needles, and unsafe medical practices. Co-infected patients demonstrated worse clinical outcomes, such as elevated liver enzymes, decompensated cirrhosis, and higher rates of hepatocellular carcinoma., Conclusions: Our review underscores the urgent need for routine HDV screening among HBV patients in Nigeria, especially given the severe clinical consequences of co-infection. The recent WHO guidelines recommending HDV screening align with our findings, which emphasize the importance of RNA-based HDV testing among HBV-positive patients to improve diagnostic accuracy. Public health efforts should prioritize tailored interventions based on geographic, age, and gender disparities in HDV prevalence. Triple infection with HIV/HBV/HDV requires integrated care models to address both immune suppressions as indicated by diminished CD4 cell count and liver disease progression, as these patients face worse outcomes. Targeted HDV screening in mostly affected demographics and geographies and improved Nigeria capacity for cheaper HDV RNA/PCR diagnostics can reduce liver-related morbidity and mortality caused by HBV, which can be worsened and accelerated by HDV coinfection.

Current guidelines recommend reflex testing for hepatitis D virus (HDV) coinfection in hepatitis B surface antigen (HBsAg)-positive patients over risk-factor based screening. We aimed to evaluate the feasibility and diagnostic yield of reflex anti-HDV testing at a Central European tertiary care center. We retrospectively included 560 consecutive patients who had a recorded (first) positive HBsAg test result at the Vienna General Hospital between 2018 and 2022. While reflex anti-HDV testing had been implemented in our hepatitis outpatient clinic (n = 153, 'reflex testing cohort'), HDV screening needed to be manually ordered in the remaining patients (n = 407, 'standard testing cohort'). Overall, 98.0% and 65.1% of patients in the reflex and standard testing cohort were screened for anti-HDV, respectively, and the overall seroprevalence of anti-HDV among screened patients was 6.7% (n = 28, reflex testing cohort: 9.3%, standard testing cohort: 5.3%). Risk factors for HDV were present in 49.1% of all included and in 89.3% of anti-HDV positive patients, respectively. Anti-HDV positive patients showed higher ALT (54 [33-83] vs. 29 [19-49] U/L; p = 0.005) and a higher proportion of low-to-undetectable HBV-DNA (61.5% vs. 33.2%; p < 0.001), as compared to anti-HDV negative patients. HDV-RNA PCR was ordered in n = 21/28 (75.0%) of anti-HDV positive patients, and 76.2% had detectable HDV-RNA. Among viremic patients, 75% and 37.5% had significant fibrosis (≥ F2) or cirrhosis (F4), respectively. The prevalence of anti-HDV among HBsAg-positive patients is considerable in a large hospital located in Central Europe. Double reflex testing, i.e., anti-HDV being triggered by the presence of HBsAg and HDV-PCR bring triggered by the presence of anti-HDV, seems warranted to increase the diagnostic yield., (© 2024. The Author(s).)

The Brazilian Amazon region is a highly endemic area for hepatitis Delta and has areas that are difficult to access. Understanding the dynamics of HDV transmission in these remote locations is important for elucidating the routes of infection. To investigate this, a molecular analysis of HDV was conducted to assess the spatio-temporal dynamics of HDV cases. Between 2010 and 2023, 35 patients were recruited from the Viral Hepatitis Outpatient Clinic in Rondônia, Brazil. Conventional PCR was used to amplify the complete HDV genome followed by nucleotide sequencing via the Sanger method. The HDV genotype was determined using maximum likelihood phylogenetic reconstruction. A Skygrid coalescent approach with a Relaxed Random Walk phylogeographic model was used for the spatio-temporal analysis. Most individuals were males (21/35), with a median age of 39 years. HDV-3 was identified in all samples (35/35; 100%). The tMRCA was estimated to be 1824, with a substitution rate of 8.2 × 10 -4 substitutions/site/year. The results suggest that HDV likely entered Brazil around 1820, in the state of Amazonas, subsequently spreading to Acre and Rondônia. Notable migration events were observed starting from 2010. This study suggests that HDV-3 has a complex evolutionary history spanning over two centuries, with intricate transmission routes in different locations in Brazil.

Chronic viral hepatitis is caused by hepatitis B virus (HBV), hepatitis C virus (HCV), or hepatitis D virus (HDV). Despite different replication strategies, all of these viruses rely on secretion through the host endoplasmic reticulum-Golgi pathway, providing potential host targets for antiviral therapy. Knockdown of transmembrane 6 superfamily member 2 (TM6SF2) in virus cell culture models reduced secretion of infectious HCV virions, HDV virions, and HBV subviral particles. Moreover, in a cohort of people with hepatitis B, a TM6SF2 polymorphism (rs58542926 CT/TT, which causes protein misfolding and reduced TM6SF2 in the liver) correlated with lower concentrations of subviral particles in blood, complementing our previous work showing decreased HCV viral load in people with this polymorphism. In conclusion, the host protein TM6SF2 plays a key role in secretion of HBV, HCV, and HDV, providing the potential for novel pan-viral agents to treat people with chronic viral hepatitis., Competing Interests: Potential conflicts of interest. T. T. has served as an advisor for Gilead, Excision BioTherapeutics, and GlaxoSmithKline (GSK) and as a speaker for GSK. T. B. has received funding from AbbVie, BMS, Gilead, MSD/Merck, Humedics, Intercept, Merz, Norgine, Novartis, Orphalan, and Sequana Medical; has served an advisor for AbbVie, Alexion, Bayer, Gilead, GSK, Eisai, Enyo Pharma, HepaRegeniX GmbH, Humedics, Intercept, Ipsen, Janssen, MSD/Merck, Novartis, Orphalan, Roche, Sequana Medical, SIRTEX, SOBI, and Shionogi; and has served as speaker for AbbVie, Alexion, Bayer, Gilead, Eisai, Falk Foundation, Intercept, Ipsen, Janssen, MedUpdate GmbH, MSD/Merck, Novartis, Orphalan, Sequana Medica, SIRTEX, and SOBI. H. L. Y. C. has served as an advisor for Aligos, Arbutus, Gilead, GSK, Roche, Vaccitech, Vir Biotechnology, and Virion Therapeutics; has been a speaker for Gilead, Roche, and Viatris; and has served on the data management boards of Aligos, Roche, Vaccitech, and Zhimeng. J. G. has served as an advisor for Novo Nordisk, Roche, AstraZeneca, Pfizer, and Boehringer Mannheim and as speaker for Novo Nordisk and Roche. M. W. D. has served as an advisor for Gilead and GSK and as speaker for GSK and Roche. All other authors report no potential conflicts of interest. 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) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America. All rights reserved. For commercial re-use, please contact reprints@oup.com for reprints and translation rights for reprints. All other permissions can be obtained through our RightsLink service via the Permissions link on the article page on our site—for further information please contact journals.permissions@oup.com.)

Hepatitis delta virus (HDV) co-infections more often result in severe hepatitis compared to hepatitis B virus (HBV) infections alone. Despite a high HDV prevalence (7.1%), information regarding circulating HDV clades is very limited in Botswana. We extracted total nucleic acid from confirmed HDV-positive samples and quantified their viral load. We then sequenced the large hepatitis delta antigen (L-HDAg) using Oxford Nanopore Technology (ONT). Genotyping was performed using the HDV Database, and HDV mutation profiling was performed on AliView. All participants with HBV genotypic information belonged to sub-genotype A1, and 80% (4/5) of them had a higher HDV viral load and a lower HBV viral load. We sequenced 75% (9/12) of the HDV-positive samples, which belonged to HDV clade 8. A total of 54 mutations were discovered, with the most prevalent being Q148R (16%), D149P (16%) and G151D (16%). Known mutations such as S117A, K131R, R139K and G151D were detected, while the other mutations were novel. Our results reveal that HDV clade 8 is the predominant clade in Botswana. The significance of all mutations remains unclear. Future studies with a larger sample size to detect other HDV clades that might be circulating in Botswana and functionally characterize the detected mutations are warranted.

Current culture systems available for studying hepatitis D virus (HDV) are suboptimal. In this study, we demonstrate that hepatocyte-like cells (HLCs) derived from human pluripotent stem cells (hPSCs) are fully permissive to HDV infection across various tested genotypes. When co-infected with the helper hepatitis B virus (HBV) or transduced to express the HBV envelope protein HBsAg, HLCs effectively release infectious progeny virions. We also show that HBsAg-expressing HLCs support the extracellular spread of HDV, thus providing a valuable platform for testing available anti-HDV regimens. By challenging the cells along the differentiation with HDV infection, we have identified CD63 as a potential HDV co-entry factor that was rate-limiting for HDV infection in immature hepatocytes. Given their renewable source and the potential to derive hPSCs from individual patients, we propose HLCs as a promising model for investigating HDV biology. Our findings offer new insights into HDV infection and expand the repertoire of research tools available for the development of therapeutic interventions., (© 2024. The Author(s).)

Background and Aims: Chronic hepatitis D infection is the most severe form of viral hepatitis and can rapidly progress to cirrhosis or hepatocellular carcinoma. Despite recommendations for systematic screening of hepatitis B surface antigen (HBsAg)-positive individuals, data from real-world studies have reported a low frequency of hepatitis D (or delta) virus (HDV) screening. Our cross-sectional analysis evaluated the diagnostic cascade for hepatitis D infection in tertiary centres and described the characteristics of HDV-positive patients., Methods: A total of 6772 individuals who tested HBsAg positive for the first time between 2018 and 2022 were retrospectively included. Demographic, clinical and laboratory data were analysed., Results: A total of 5748 HBsAg-positive individuals (84.9%) were screened for HDV infection. The screening rate varied from 63% to 97% according to the screening strategy used in the centres including or not HDV reflex testing. The prevalence of HDV infection was 6.3%. HDV RNA levels were determined in 285 of the 364 (78.3%) HDV antibody screening-positive patients, and 167 (58.6%) had active HDV infection. 66.8% were males, with a mean age of 44.9 years. A total of 97.5% were born abroad, and 92.9% were HBeAg negative. At the time of diagnosis, HDV RNA levels were 6.0 Log UI/mL; 60.1% had alanine aminotransferase >40 U/L, and 56.3% had significant fibrosis (≥F2), including 41.6% with cirrhosis. The most common genotype was HDV-1 (75.4%). Coinfections were not uncommon: 7.4% were HIV positive, and 15.0% were HCV antibody positive., Conclusions: The present study highlights the need for increased screening and monitoring of HDV infection. Reflex testing helps to identify HDV-infected individuals., (© 2024 The Author(s). Liver International published by John Wiley & Sons Ltd.)

Background & Aims: Bulevirtide (BLV), a first-in-class entry inhibitor, is approved in Europe for the treatment of chronic hepatitis delta (CHD). BLV monotherapy was superior to delayed treatment at week (W) 48, the primary efficacy endpoint, in the MYR301 study (NCT03852719). Here, we assessed if continued BLV therapy until W96 would improve virologic and biochemical response rates, particularly among patients who did not achieve virologic response at W24., Methods: In this ongoing, open-label, randomized phase III study, patients with CHD (N = 150) were randomized (1:1:1) to treatment with BLV 2 mg/day (n = 49) or 10 mg/day (n = 50), each for 144 weeks, or to delayed treatment for 48 weeks followed by BLV 10 mg/day for 96 weeks (n = 51). Combined response was defined as undetectable hepatitis delta virus (HDV) RNA or a decrease in HDV RNA by ≥2 log 10 IU/ml from baseline and alanine aminotransferase (ALT) normalization. Other endpoints included virologic response, ALT normalization, and change in HDV RNA., Results: Of 150 patients, 143 (95%) completed 96 weeks of the study. Efficacy responses were maintained and/or improved between W48 and W96, with similar combined, virologic, and biochemical response rates between BLV 2 and 10 mg. Of the patients with a suboptimal early virologic response at W24, 43% of non-responders and 82% of partial responders achieved virologic response at W96. Biochemical improvement often occurred independently of virologic response. Adverse events were mostly mild, with no serious adverse events related to BLV., Conclusions: Virologic and biochemical responses were maintained and/or increased with longer term BLV therapy, including in those with suboptimal early virologic response. BLV monotherapy for CHD was safe and well tolerated through W96., Impact and Implications: In July 2023, bulevirtide was fully approved for the treatment of chronic hepatitis delta (CHD) in Europe based on clinical study results from up to 48 weeks of treatment. Understanding the efficacy and safety of bulevirtide over the longer term is important for healthcare providers. In this analysis, we demonstrate that bulevirtide monotherapy for 96 weeks in patients with CHD was associated with continued improvements in combined, virologic, and biochemical responses as well as liver stiffness from week 48 at both the 2 mg and 10 mg doses. Patients with suboptimal virologic responses to bulevirtide at week 24 also benefited from continued therapy, with the majority achieving virologic response or biochemical improvement by week 96., Gov Identifier: NCT03852719., (Copyright © 2024 The Authors. Published by Elsevier B.V. All rights reserved.)

Background: Hepatitis B virus (HBV) DNA may become integrated into the human genome of infected human hepatocytes. Expression of integrations can produce the surface antigen (HBsAg) that is required for synthesis of hepatitis D virus (HDV) particles and the abundant subviral particles in the blood of HBV- and HDV-infected subjects. Knowledge about the extent and variation of HBV integrations and impact on chronic HDV is still limited., Methods: We investigated 50 pieces of liver explant tissue from 5 patients with hepatitis D-induced cirrhosis, using a deep-sequencing strategy targeting HBV RNA., Results: We found that integrations were abundant and highly expressed, with large variation in the number of integration-derived (HBV/human chimeric) reads, both between and within patients. The median number of unique integrations for each patient correlated with serum levels of HBsAg. However, most of the HBV reads represented a few predominant integrations., Conclusions: The results suggest that HBV DNA integrates in a large proportion of hepatocytes, and that the HBsAg output from these integrations vary >100-fold depending on clone size and expression rate. A small proportion of the integrations seems to determine the serum levels of HBsAg and HDV RNA in HBV/HDV coinfected patients with liver cirrhosis., Competing Interests: Potential conflicts of interest. All authors: No reported conflicts of interest. 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) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background: This study assessed the epidemiology of hepatitis delta virus (HDV) within the University of Utah UHealth health care system (2000-2021)., Methods: Analysis of HDV/HBV testing, diagnostic codes, liver enzymes, and comorbidities was performed., Results: Among the 1962 HBV patients, only 22.2% underwent HDV testing, revealing an 8.3% positivity rate for HDV coinfections. This study observed a consistent increase in HBV and HDV cases, with higher HDV detection rates linked to increased testing. Limited HDV testing and potential screening biases were evident., Discussion: Improved HDV testing and surveillance are crucial for early detection and implementation of targeted therapies., Competing Interests: Potential conflicts of interest. M. L. W. and K. M. L. have current funding from Gilead Sciences, Inc. 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., (© The Author(s) 2024. Published by Oxford University Press on behalf of Infectious Diseases Society of America.)

Background and Aims: We aimed to characterize the epidemiologic and comorbidities profiles of patients with chronic Hepatitis D (CHD) followed in clinical practice in Italy and explored their interferon (IFN) eligibility., Methods: This was a cross-sectional study of the PITER cohort consisting of consecutive HBsAg-positive patients from 59 centers over the period 2019-2023. Multivariable analysis was performed by logistic regression model., Results: Of 5492 HBsAg-positive enrolled patients, 4152 (75.6%) were screened for HDV, 422 (10.2%) were anti-HDV positive. Compared with HBsAg mono-infected, anti-HDV positive patients were more often younger, non-Italians, with a history of drug use, had elevated alanine transaminase (ALT), cirrhosis, or hepatocellular carcinoma (HCC). Compared with Italians, anti-HDV positive non-Italians were younger (42.2% age ≤ 40 years vs. 2.1%; P < 0.001), more often females (males 43.0% vs. 68.6%; P < 0.001) with less frequent cirrhosis and HCC. HDV-RNA was detected in 63.2% of anti-HDV-positive patients, who were more likely to have elevated ALT, cirrhosis, and HCC. Extrahepatic comorbidities were present in 47.4% of anti-HDV positive patients and could affect the eligibility of IFN-containing therapies in at least 53.0% of patients in care., Conclusions: CHD affects young, foreign-born patients and older Italians, of whom two-thirds had cirrhosis or HCC. Comorbidities were frequent in both Italians and non-Italians and impacted eligibility for IFN., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Author(s). Published by Elsevier Ltd.. All rights reserved.)

Background and Aims: Chronic hepatitis delta represents a major global health burden. Clinical features of hepatitis D virus (HDV) infection vary largely between different regions worldwide. Treatment approaches are dependent on the approval status of distinct drugs and financial resources., Methods: The Hepatitis Delta International Network (HDIN) registry involves researchers from all continents (Wranke, Liver International 2018). We here report long-term follow-up data of 648 hepatitis D patients recruited by 14 centres in 11 countries. Liver-related clinical endpoints were defined as hepatic decompensation (ascites, encephalopathy and variceal bleeding), liver transplantation, hepatocellular carcinoma or liver-related death., Results: Patient data were available from all continents but Africa: 22% from Eastern Mediterranean, 32% from Eastern Europe and Central Asia, 13% from Central and Southern Europe, 14% from South Asia (mainly Pakistan) and 19% from South America (mainly Brazil). The mean follow-up was 6.4 (.6-28) years. During follow-up, 195 patients (32%) developed a liver-related clinical event after 3.5 (±3.3) years. Liver cirrhosis at baseline and a detectable HDV RNA test during follow-up were associated with a worse clinical outcome in multivariate regression analysis while patients receiving interferon alfa-based therapies developed clinical endpoints less frequently. Patients from South Asia developed endpoints earlier and had the highest mortality., Conclusions: The HDIN registry confirms the severity of hepatitis D and provides further evidence for HDV viraemia as a main risk factor for disease progression. Hepatitis D seems to take a particularly severe course in patients born in Pakistan. There is an urgent need to extend access to antiviral therapies and to provide appropriate education about HDV infection., (© 2024 The Author(s). Liver International published by John Wiley & Sons Ltd.)

Background: The use of nucleos(t)ide analogs (NAs) with a high genetic barrier to resistance, namely entecavir and tenofovir, has improved the efficacy of antiviral prophylaxis against hepatitis B virus (HBV) recurrence after liver transplantation (LT). However, the optimal duration and dosage of hepatitis B immunoglobulin (HBIG) administration, particularly in patients transplanted for HBV and hepatitis D virus (HDV) coinfection, remains controversial., Methods: We evaluated 28 patients transplanted for HBV/HDV cirrhosis. After LT, each patient received a fixed scheme of low-dose HBIG plus NA for 6 mo post-LT and then continued with long-term NA prophylaxis (entecavir: 8, tenofovir: 20 patients)., Results: During 72 mo of follow-up, reappearance of hepatitis B surface antigen at low titers was observed in 1 (3.6%) patient at 33 mo after HBIG discontinuation, which became negative after a single dose of HBIG 1000 IU/L, whereas both serum HBV DNA and HDV RNA remained persistently undetectable and without any clinical or biochemical evidence of HBV/HDV recurrence., Conclusions: We showed for the first time the efficacy of a short, fixed scheme of low-dose HBIG plus NA followed by long-term NA monoprophylaxis against HBV/HDV recurrence after LT, although careful follow-up is needed after HBIG discontinuation, whereas further larger studies are needed to confirm these findings., Competing Interests: The authors declare no funding or conflicts of interest., (Copyright © 2024 Wolters Kluwer Health, Inc. All rights reserved.)

The hepatitis delta virus (HDV) is a unique pathogen with significant global health implications, affecting individuals who are coinfected with the hepatitis B virus (HBV). HDV infection has profound clinical consequences, manifesting either as coinfection with HBV, resulting in acute hepatitis and potential liver failure, or as superinfection in chronic HBV cases, substantially increasing the risk of cirrhosis and hepatocellular carcinoma. Given the complex dynamics of HDV infection and the urgent need for advanced research tools, this article introduces vHDvDB 2.0, a comprehensive HDV full-length sequence database. This innovative platform integrates data preprocessing, secondary structure prediction, and epidemiological research tools. The primary goal of vHDvDB 2.0 is to consolidate HDV sequence data into a user-friendly repository, thereby facilitating access for researchers and enhancing the broader scientific understanding of HDV. The significance of this database lies in its potential to streamline HDV research by providing a centralized resource for analyzing viral sequences and exploring genotype-specific characteristics. It will also enable more in-depth research within the HDV sequence domains.

Background: HDV antibody testing is recommended for universal screening and as the first line in an HDV double reflex testing strategy for effectively identifying patients with active infection for therapeutic treatments., Objective: The aim of this study is to evaluate the performance of a newly developed ARCHITECT HDV Total Ig (ARCHITECT HDV Ig) prototype assay., Study Design: Performance characteristics were determined for the ARCHITECT HDV Ig and a reference test, LIAISON XL Anti-HDV using a well-characterized specimen panel, comprising HDV RNA positive (n = 62) and negative (n = 70) samples, and healthy US blood donors., Results: Healthy US blood donors (n=200) showed 99.5% (199/200, 95%CI=97.65-99.98) specificity with ARCHITECT HDV Ig and 98.5 % (197/200, 95 %CI = 96.10-99.64) with LIAISON Anti-HDV. Among known HDV RNA positive samples, ARCHITECT HDV Ig detected 59/62 demonstrating 95.2 % sensitivity while LIAISON Anti-HDV sensitivity was 90.3 % (56/62). Among 101 HBV positive samples, 70 were reactive in the ARCHITECT test, 59 of which tested positive for HDV RNA for a positive predictive value (PPV) for the presence of HDV RNA was 84.3 %. For LIAISON Anti-HDV, 79 specimens were reactive and 56 contained HDV RNA: PPV for HDV RNA was 70.9 %. Among 70 HDV RNA negative samples, 39 were HBV positive. ARCHITECT HDV Ig negative predictive value (NPV) was 71.8 % and LIAISON Anti-HDV NPV was 41 % for the HBV positive group, respectively., Conclusion: When compared to the LIASON Anti-HDV test, the ARCHITECT HDV Ig assay demonstrated enhanced sensitivity and specificity and better NPV and PPV values for HDV RNA status. The ARCHITECT HDV Ig assay represents a promising tool for universal screening of all HBsAg-positive persons., Competing Interests: Declaration of competing interest X.Q., A.H., A.O., A.H., M.K., M.R. and G.C. are employees and shareholders of Abbott Laboratories stock., (Copyright © 2024. Published by Elsevier B.V.)

Patients living with HIV infection (PLWH) are at risk of acquiring HBV and HDV. The present study aimed to determine the prevalence and characteristics of HIV-HDV-HBV tri-infection in comparison with HIV-HBV coinfection and to estimate severities and outcomes of associated liver diseases in Mauritanian PLWH. Two-hundred-ninety-two consecutive HBsAg-positive PLWH were included (mean age: 37 years). Clinical data were recorded. Anti-HDV antibodies, HBV and HDV viral loads (VLs) and genotype were determined. APRI, FIB-4 and FibroScan were performed to evaluate the severity of liver disease. The anti-HDV antibodies prevalence was 37% and HDV RNA was positive in 40.7% of patients. Genetic diversities were found with HDV genotype 1 (93%) and HBV genotypes D (42.5%) and E (38%). The HBV VL was detectable in 108 patients at inclusion, and mutations associated with HBV resistance were found in 20. For almost all variables studied, including FIB-4 and APRI scores, no significant differences were found between anti-HDV-Ab positive or negative patients. FibroScan examination, which was performed in 110 patients at end-of-follow-up showed higher, but NS values, in HDV positive patients. After a mean follow-up of 24.55 ± 8.01 months (n = 217 patients), a highly significant worsening of APRI and FIB-4 scores was found. Moreover, patients with HDV showed more severe liver disease progression despite an efficient therapy. In a substantial Mauritanian cohort of relatively young PLWH, we found high HDV prevalence and worsening liver disease. In high-risk countries, screening for HDV and providing appropriate follow-up and treatments are warranted in PLWH., (© 2024 The Authors. Journal of Viral Hepatitis published by John Wiley & Sons Ltd.)

Chronic infection of hepatitis B virus (HBV) and hepatitis D virus (HDV) causes the most severe form of viral hepatitis. Due to the dependence on HBV, HDV was deemed to co-evolve and co-migrate with HBV. However, we previously found that the naturally occurred HDV/HBV combinations do not always reflect the most efficient virological adaptation (Wang et al., 2021). Moreover, regions with heavy HBV burden do not always correlate with high HDV prevalence (e.g., East Asia), and vice versa (e.g., Central Asia). Herein, we systematically elucidated the spatiotemporal evolutionary landscape of HDV to understand the unique epidemic features of HDV. We found that the MRCA of HDV was from South America around the late 13th century, was globally dispersed mainly via Central Asia, and evolved into eight genotypes from the 19th to 20th century. In contrast, the MRCA of HBV was from Europe ∼23.7 thousand years ago (Kya), globally dispersed mainly via Africa and East Asia, and evolved into eight genotypes ∼1100 years ago. When HDV stepped in, all present-day HBV genotypes had already formed and its global genotypic distribution had stayed stable geographically. Nevertheless, regionalized HDV adapted to local HBV genotypes and human lineages, contributing to the global geographical separation of HDV genotypes. Additionally, a sharp increase in HDV infections was observed after the 20th century. In conclusion, HDV exhibited a distinct spatiotemporal distribution path compared with HBV. This unique evolutionary relationship largely fostered the unique epidemic features we observe nowadays. Moreover, HDV infections may continue to ramp up globally, thus more efforts are urgently needed to combat this disease., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Hepatitis delta virus (HDV) is a satellite of hepatitis B virus (HBV), which requires the HBV surface antigen (HBsAg) for its assembly and propagation. Although countries affected by HBV infection in Africa are well identified, data on HDV infection are still scarce, like in Nigeria, where HBV infection is endemic. In this study, we aimed to determine the prevalence of HDV infection and identify the circulating genotypes/strains in the country. A nationwide study was performed on 1281 HBsAg-positive samples collected from patients across eleven sites drawn from the six geopolitical zones in Nigeria. Anti-HDV antibody (HDV-Ab) screening and HDV-RNA viral load quantification were performed using a commercial ELISA assay and real-time RT-PCR kit, respectively. HDV genotyping was performed by the Sanger sequencing of amplicons from the so-called R0 region of the viral genome, followed by phylogenetic analyses. Of the 1281 HBsAg-positive samples, 61 (4.8%) were HDV-Ab positive, among which, 12 (19.7%) were HDV-RNA positive. Genotypes were obtained for nine of them: seven "African" HDV-1, one "Asian/European" HDV-1 and one HDV-6. This study shows that Nigeria is a country of low HDV prevalence where mainly "African" genotype-1 strains are circulating.

The interaction of multiple viruses in one host is thought to enhance the development of mutations. However, the impact of hepatitis D virus (HDV) positivity on the development of unique hepatitis B virus (HBV) mutations among people living with human immunodeficiency virus (HIV) (PLWH) remains poorly understood in African countries, including Botswana. We used HBV sequences generated from the Botswana Combination Prevention Project (BCPP), which is the largest pair-matched cluster-randomized HIV trial in Botswana. Only participants with available HBV sequences ( n = 55) were included in our study ([HIV/HBV-positive ( n = 50) and HIV/HBV/HDV-positive ( n = 5)]. Geno2pheno was used to determine HBV genotypes, and HBV surface region sequences (all subgenotype A1) were aligned in AliView for mutational analysis, while the impact of mutations was assessed using Phyre2. Our results identified 182 common mutations between the two groups. In the HIV/HBV/HDV cohort, only three mutations ( L95W , W156Q , C221Y ) were classified as deleterious, with only L95W being the most frequent. In the HIV/HBV cohort, four mutations ( W199R , C221A , C221S , W223G ) were also classified as deleterious. Our results demonstrate the presence of unique HBV mutations among the HIV/HBV/HDV-positive cohort. Functional characterization of these mutations is recommended to determine their effect on HDV.

Background: In a phase 3 trial, bulevirtide monotherapy led to a virologic response in patients with chronic hepatitis D. Pegylated interferon (peginterferon) alfa-2a is recommended by guidelines as an off-label treatment for this disease. The role of combination therapy with bulevirtide and peginterferon alfa-2a, particularly with regard to finite treatment, is unclear., Methods: In this phase 2b, open-label trial, we randomly assigned patients to receive peginterferon alfa-2a alone (180 μg per week) for 48 weeks; bulevirtide at a daily dose of 2 mg or 10 mg plus peginterferon alfa-2a (180 μg per week) for 48 weeks, followed by the same daily dose of bulevirtide for 48 weeks; or bulevirtide at a daily dose of 10 mg alone for 96 weeks. All the patients were followed for 48 weeks after the end of treatment. The primary end point was an undetectable level of hepatitis D virus (HDV) RNA at 24 weeks after the end of treatment. The primary comparison was between the 10-mg bulevirtide plus peginterferon alfa-2a group and the 10-mg bulevirtide monotherapy group., Results: A total of 24 patients received peginterferon alfa-2a alone, 50 received 2 mg and 50 received 10 mg of bulevirtide plus peginterferon alfa-2a, and 50 received 10 mg of bulevirtide monotherapy. At 24 weeks after the end of treatment, HDV RNA was undetectable in 17% of the patients in the peginterferon alfa-2a group, in 32% of those in the 2-mg bulevirtide plus peginterferon alfa-2a group, in 46% of those in the 10-mg bulevirtide plus peginterferon alfa-2a group, and in 12% of those in the 10-mg bulevirtide group. For the primary comparison, the between-group difference was 34 percentage points (95% confidence interval, 15 to 50; P<0.001). At 48 weeks after the end of treatment, HDV RNA was undetectable in 25% of the patients in the peginterferon alfa-2a group, in 26% of those in the 2-mg bulevirtide plus peginterferon alfa-2a group, in 46% of those in the 10-mg bulevirtide plus peginterferon alfa-2a group, and in 12% of those in the 10-mg bulevirtide group. The most frequent adverse events were leukopenia, neutropenia, and thrombocytopenia. The majority of adverse events were of grade 1 or 2 in severity., Conclusions: The combination of 10-mg bulevirtide plus peginterferon alfa-2a was superior to bulevirtide monotherapy with regard to an undetectable HDV RNA level at 24 weeks after the end of treatment. (Funded by Gilead Sciences; MYR 204 ClinicalTrials.gov number, NCT03852433.)., (Copyright © 2024 Massachusetts Medical Society.)