Growing Awareness: Limited Testing and Screening Bias for Hepatitis Delta Virus in Utah 2000-2021.

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.

JAK1 promotes HDV replication and is a potential target for antiviral therapy.

BACKGROUND & AIMS: Chronic co-infection with HBV and HDV leads to the most aggressive form of chronic viral hepatitis. To date, no treatment induces efficient viral clearance, and a better characterization of virus-host interactions is required to develop new therapeutic strategies. METHODS: Using loss-of-function strategies, we validated the unexpected proviral activity of Janus kinase 1 (JAK1) - a key player in innate immunity - in the HDV life cycle and determined its mechanism of action on HDV through various functional analyses including co-immunoprecipitation assays. RESULTS: We confirmed the key role of JAK1 kinase activity in HDV infection. Moreover, our results suggest that JAK1 inhibition is associated with a modulation of ERK1/2 activation and S-HDAg phosphorylation, which is crucial for viral replication. Finally, we showed that FDA-approved JAK1-specific inhibitors are efficient antivirals in relevant in vitro models including primary human hepatocytes. CONCLUSIONS: Taken together, we uncovered JAK1 as a key host factor for HDV replication and a potential target for new antiviral treatment. IMPACT AND IMPLICATIONS: Chronic hepatitis D is the most aggressive form of chronic viral hepatitis. As no curative treatment is currently available, new therapeutic strategies based on host-targeting agents are urgently needed. Here, using loss-of-function strategies, we uncover an unexpected interaction between JAK1, a major player in the innate antiviral response, and HDV infection. We demonstrated that JAK1 kinase activity is crucial for both the phosphorylation of the delta antigen and the replication of the virus. By demonstrating the antiviral potential of several FDA-approved JAK1 inhibitors, our results could pave the way for the development of innovative therapeutic strategies to tackle this global health threat.

Bulevirtide monotherapy in patients with chronic HDV: Efficacy and safety results through week 96 from a phase III randomized trial.

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 log10 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.

ICTV Virus Taxonomy Profile: Kolmioviridae 2024.

Kolmioviridae is a family for negative-sense RNA viruses with circular, viroid-like genomes of about 1.5-1.7 kb that are maintained in mammals, amphibians, birds, fish, insects and reptiles. Deltaviruses, for instance, can cause severe hepatitis in humans. Kolmiovirids encode delta antigen (DAg) and replicate using host-cell DNA-directed RNA polymerase II and ribozymes encoded in their genome and antigenome. They require evolutionary unrelated helper viruses to provide envelopes and incorporate helper virus proteins for infectious particle formation. This is a summary of the International Committee on Taxonomy of Viruses (ICTV) Report on the family Kolmioviridae, which is available at ictv.global/report/kolmioviridae.

Epidemiology of hepatitis D virus infection in Europe: Is it vanishing?

Co-infection with hepatitis delta virus (HDV) is a challenging health care problem worldwide, estimated to occur in approximately 5%-10% of patients with chronic hepatitis B virus (HBV) infection. While HBV prevalence is decreasing globally, the prevalence of HDV infection is rising in some parts mainly due to injection drug use, sexual transmission and immigration from high endemicity areas. Eastern Europe and the Mediterranean are among the regions with high rates of endemicity for HDV and the immigration from high endemicity areas to Central and Western Europe has changed the HDV epidemiology. We aimed to review the prevalence of HDV infection in Europe. A paucity of publication appears in many European countries. Prevalence studies from some countries are old dated and some other countries did not report any prevalence studies. The studies are accumulated in few countries. Anti-HDV prevalence is high in Greenland, Norway, Romania, Sweden and Italy. Belgium, France, Germany, Spain, Switzerland, Turkey and United Kingdom reported decreasing prevalences. Among cirrhotic HBV patients, Germany, Italy and Turkey reported higher rates of HDV. The studies including centres across the Europe reported that HIV-HBV coinfected individuals have higher prevalence of HDV infection. The immigrants contribute the HDV infection burden in Greece, Italy, and Spain in an increasing rate. Previous studies revealed extremely high rates of HDV infection in Germany, Greece, Italy and Sweden. The studies report a remarkably high prevalence of hepatitis delta among HIV/HBV-coinfected individuals, individuals who inject drugs, immigrants and severe HBV infected patients across Europe. The HDV infection burden still appears to be significant. In the lack of an effective HDV therapy, prevention strategies and active screening of HBV/HDV appear as the most critical interventions for reducing the burden of liver disease related to HDV infection in Europe.

The elimination of hepatitis D as a public health problem: Needs and challenges.

Infection with hepatitis D virus leads to liver disease and cancer most rapidly of all hepatitis viruses. However, knowledge about hepatitis D remains poor and the burden and impact are underestimated, even though some 12-15 million people mainly in low- and middle-income countries may be affected. Its epidemiology is changing, with increasing migration leading to increased risks of infection and disease. A recent Viral Hepatitis Prevention Board meeting reviewed the current epidemiological status, improvements in diagnostic testing, advances in the development of novel antiviral agents in phase III trials and the need for a greater public health response, such as new guidelines and recommended testing of all people newly identified as infected with hepatitis B virus for hepatitis D virus infection. It identified issues and needs for attention with regard to prevention, diagnosis and treatment.

Hepatitis D double reflex testing of all hepatitis B carriers in low-HBV- and high-HBV/HDV-prevalence countries.

Hepatitis D virus (HDV) infection occurs as a coinfection with hepatitis B and increases the risk of hepatocellular carcinoma, decompensated cirrhosis, and mortality compared to hepatitis B virus (HBV) monoinfection. Reliable estimates of the prevalence of HDV infection and disease burden are essential to formulate strategies to find coinfected individuals more effectively and efficiently. The global prevalence of HBV infections was estimated to be 262,240,000 in 2021. Only 1,994,000 of the HBV infections were newly diagnosed in 2021, with more than half of the new diagnoses made in China. Our initial estimates indicated a much lower prevalence of HDV antibody (anti-HDV) and HDV RNA positivity than previously reported in published studies. Accurate estimates of HDV prevalence are needed. The most effective method to generate estimates of the prevalence of anti-HDV and HDV RNA positivity and to find undiagnosed individuals at the national level is to implement double reflex testing. This requires anti-HDV testing of all hepatitis B surface antigen-positive individuals and HDV RNA testing of all anti-HDV-positive individuals. This strategy is manageable for healthcare systems since the number of newly diagnosed HBV cases is low. At the global level, a comprehensive HDV screening strategy would require only 1,994,000 HDV antibody tests and less than 89,000 HDV PCR tests. Double reflex testing is the preferred strategy in countries with a low prevalence of HBV and those with a high prevalence of both HBV and HDV. For example, in the European Union and North America only 35,000 and 22,000 cases, respectively, will require anti-HDV testing annually.

Hepatitis delta virus: Disease assessment and stratification.

Hepatitis D virus (HDV) causes one of the most severe forms of hepatitis in people with chronic hepatitis B (CHB) infection. Timely and accurate assessment of hepatitis delta virus (HDV) and disease stratification is mandatory for thorough pre-therapeutic evaluation for prioritizing treatment and outcome prediction. Viral biomarkers associated with HDV and hepatitis B virus (HBV) are crucial to aid in diagnosis, and monitoring of serum viral nucleic acids for both viruses is recommended. Liver biopsy remains the gold standard for staging of liver fibrosis and grading of histological activity and should remain central for diagnostic purposes, but is also of importance for research to enhance our understanding of HDV. The emergence of novel non-invasive tests for the assessment of liver fibrosis in HDV patients coupled with the well-recognized potential complications of liver biopsy has resulted in reduced utility of liver biopsy in clinical practice. Preliminary data suggest that these emerging non-invasive modalities appear to be reliable, and their use is supported, similar to other viral hepatitis. Nevertheless, further validation is required before their widespread adoption into clinical practice.

The changing epidemiology of delta hepatitis in Türkiye over three decades: A systematic review.

Hepatitis D virus (HDV) infection represents the most serious form of chronic hepatitis. Turkey is among the countries with high HDV and intermediate hepatitis B virus prevalence. In Turkey, hepatitis B virus (HBV) vaccine series was included in the routine vaccination program in 1998. There have been regional differences in prevalence of HBV and HDV. Although a decline in HDV prevalence is estimated, there are uncertainties about the epidemic patterns of it. HDV prevalence was studied in varying groups and geographic regions. In this study, we aimed to analyse hepatitis D epidemiology in all groups and geographic regions in recent 35 years. During the study period of 35 years, 111 publications were noted. The analysis was done on the basis of three periods: 1999 and before (Period 1), 2000-2009 (Period 2), and 2010 and after (Period 3). The groups studied included inactive carrier state, chronic hepatitis B, all HBsAg-positive individuals and special groups. Among inactive HBV carriers, HDV prevalence did not change significantly over three decades. Among patients with chronic hepatitis, studies reported decreasing (from Period 1 to Period 2) and then increasing (from Period 2 to period 3) HDV prevalence. The studies including all HBsAg-positive patients reported decreasing (from Period 1 to Period 2) and then increasing (from Period 2 to period 3) HDV prevalence. Cumulative data of these 3 groups were taken to reveal HDV prevalence in HBV-infected patients, and it showed decreasing (from Period 1 to Period 2) and then increasing (from Period 2 to period 3) HDV prevalence. Cumulative data of these 3 groups analysed according to the geographic regions of the country showed that Eastern and Southeastern Anatolia regions still have a high burden of HDV. The study showed that although HDV prevalence decreased from 8.3% in Period 1 to 4.8% in Period 2, it tended to increase 5.5% in Period 3. HDV infection is still a healthcare problem in Turkey.

Does hepatitis delta virus have a preference for hepatitis B virus genotype? A systematic review of the literature.

Hepatitis delta virus (HDV) is a deficient virus that requires the surface proteins of Hepatitis B virus (HBV) to complete its replication. HDV is thus only found in those already infected with HBV (~5% worldwide). There are eight different HDV genotypes (1-8) and 10 HBV genotypes (A-J), each having fairly distinct geographic distributions. While their pairings may be coincidental based on epidemiological occurrence, some evidence exists regarding possible virologic basis for genotype dominance and patterns. Here we sought to determine which HBV genotype is most often linked with active HDV infection and speculate on whether this may represent a viral 'preference'. Electronic databases with OVID Medline were comprehensively searched for studies published between 1977 and 2022 indexing the word 'genotype' and all permutations of 'HDV' (hepatitis D virus, hepatitis delta, etc.). Primary studies of patient samples reporting genotype data for either or both of HDV and HBV were tabulated. The initial search revealed 419 articles and was narrowed to 133 studies reporting genotype data for either or both HBV and HDV. We limited our search to cases with detectable HDV RNA. These represented over 5800 samples from over 70 countries. Of these, 1947 samples had paired genotype data for both viruses. The most common pairing was HDV-1 with HBV-D, but it remains unclear whether this represents a viral 'preference' or mere co-endemicity of the two viruses. Determining if there is a virologic link between HBV and HDV genotypes may have important implications for emerging HDV and HBV research.

Hepatitis delta virus infection prevalence, diagnosis and treatment in the Middle East: A scoping review.

Hepatitis D virus (HDV) infection is a global public health concern, especially because of its unique existence in the presence of hepatitis B virus infection. HDV infection is estimated to affect 12 million people globally. Having a clearer understanding of its prevalence in all regions of the world is essential for helping direct preventive and early interventional treatment. This mini-review assessed the literature over the last 10 years to determine the prevalence, diagnostic means and treatment guidelines available for HDV in the Middle East. The search found limited data available in 21 articles, of which 18 were studies focused on Iran. Prevalence rates ranged dramatically among the countries, and none of the 12 countries included in the search had specific HDV guidelines. This review highlights the urgent need for more precise data for the Middle East region to help establish early diagnosis and treatment options for HDV.

Impact of hepatitis D reflex testing on the future disease burden: A modelling analysis.

Chronic hepatitis D (CHD) is a severe form of viral hepatitis that leads to liver cirrhosis and hepatocellular carcinoma. CHD is underdiagnosed, and this study aimed to assess the impact of hepatitis D reflex testing in HBsAg-positive individuals in Spain over the next 8 years. Two scenarios were compared: the current situation (7.6% of HBsAg-positive patients tested for anti-HDV) and reflex testing for all positive samples. A decision tree model was designed to simulate the CHD care cascade. Implementing reflex testing would increase anti-HDV detection to 5498 cases and HDV-RNA to 3225 cases. Additionally, 2128 more patients would receive treatment, with 213 achieving undetectable HDV-RNA levels. The cost per anti-HDV case detected would be €132. In the median time of the analysis, liver complications (decompensated cirrhosis, HCC and liver-related deaths) would be reduced by 35%-38%, implying an estimated cost savings of 36 million euros associated with the management of such complications. By 2030, implementing anti-HDV reflex testing would reduce the clinical and economic burden of CHD by 35%-38%.

Successful clinical and virological outcomes of liver transplantation for HDV/HBV-related disease after long-term discontinuation of hepatitis B immunoglobulins.

BACKGROUND: Indefinite, long-term administration of hepatitis B immunoglobulins (HBIg), together with a third generation nucleos(t)ide analog (NA), is the currently recommended prophylactic strategy to prevent viral recurrence after liver transplantation (LT) for Hepatitis Delta virus (HDV)/Hepatitis B virus (HBV)-related disease. METHODS: We retrospectively analyzed the safety and long-term clinical and virological outcomes of a consecutive cohort of 16 patients (10 males, median age 64.5, range 41-75) transplanted for HDV/HBV-related cirrhosis at our Institution, who discontinued HBIg after a median of 24.5 months (range 15-116) after transplant. All patients continued prophylaxis with same NA used before LT. Recurrence of HDV/HBV infection was defined as reappearance of serum HDV-RNA with detectable serum HBsAg and/or HBV-DNA. RESULTS: The median follow-up after LT was 138 months (range 73-316) and 110 months (range 52-200) after HBIg withdrawal. All patients were HBsAg-positive, HBV-DNA negative, and anti-HDV positive at the time of LT and without coinfections with HCV or HIV. Patients were followed with biochemical and virological tests every 3-6 months after HBIg withdrawal. No recurrences of HDV/HBV infection or disease were observed during monoprophylaxis with NA. In addition, eight patients (50%) spontaneously developed anti-HBs titers above 10 IU/L at a median of 74 months (range 58-140) following HBIG discontinuation. CONCLUSIONS: HBIg withdrawal after LT is a safe and efficacious strategy in patients transplanted for HDV/HBV disease and is frequently associated with the spontaneous development of serological immunity against HBV. These data call for a revision of current prophylactic recommendations in this setting.

Prevalence and genotypes distribution of virus hepatitis B and hepatitis delta virus in chronic liver diseases in Kazakhstan.

BACKGROUND: The geographical distribution of hepatitis B virus (HBV) and hepatitis D virus (HDV) genotypes is uneven and has its own clinical and organizational implications for health systems. Despite the introduction of vaccination and successful antiviral therapy the prevalence of chronic hepatitis B (with or without delta agent) increased over the past 5 years. This study aimed for the first time to investigate the molecular epidemiology of HBV and HDV in Kazakhstan. METHODS: Total 834 chronic hepatitis B (with or without delta agent) patients were included to the study from November 2017 to June 2019. The material was collected from the regional hepatological сenters from 13 cities of Kazakhstan. Genotyping of HBV/HDV isolates was carried out using phylogenetic analysis of null-binary sequences of Kazakhstani isolates, in comparison with the reference sequences. Nucleotide sequence alignment was performed using the ClustalW algorithm, the "neighbor-joining" method was used for the construction of phylogenetic trees and subsequent analysis. RESULTS: Overall 341 samples were PCR-positive and genotyped for HBV. Comparison and phylogenetic analysis of nucleotide sequences of HBV isolates showed that they were represented by genotypes HBV-D (95.9%), HBV-A (3.5%) and HBV-C (0.6%). At the same time, the identity of the nucleotide sequences of Kazakhstani isolates were: HBV-D (95-100%); HBV-A (97.2-100%) and HBV-C (99%). 256 samples were PCR positive and genotyped for HDV, all of them belonged to genotype 1. CONCLUSION: This study describes for the first time the molecular epidemiology of HBV and HDV in Kazakhstan. The data obtained expand the knowledge of the global epidemiology of viruses; have potential implications for public health policy and for further clinical research on chronic hepatitis in Kazakhstan. TRIAL REGISTRATION: ClinicalTrials.gov NCT05095181 (registered on 27/10/2021).

Recent prevalence and characteristics of patients with hepatitis delta virus in Hokkaido, Japan.

AIM: Although hepatitis delta virus (HDV) coinfection with hepatitis B virus (HBV) is a global health concern, the global prevalence of HDV infections remains unknown due to insufficient data in many countries. In Japan, HDV prevalence has not been updated for over 20 years. We aimed to investigate the recent prevalence of HDV infections in Japan. METHODS: We screened 1264 consecutive patients with HBV infection at Hokkaido University Hospital between 2006 and 2022. Patients' serums were preserved and subsequently tested for HDV antibody (immunoglobulin-G). Available clinical information was collected and analyzed. We compared the changes in liver fibrosis using the Fibrosis-4 (FIB-4) index between propensity-matched patients with and without the evidence of anti-HDV antibodies and corrected for baseline FIB-4 index, nucleoside/nucleotide analog treatment, alcohol intake, sex, HIV coinfection, liver cirrhosis, and age. RESULTS: After excluding patients without properly stored serums and those lacking appropriate clinical information, 601 patients with HBV were included. Of these, 1.7% of patients had detectable anti-HDV antibodies. Patients with anti-HDV antibody serum positivity had a significantly higher prevalence of liver cirrhosis, significantly lower prothrombin time, and a higher prevalence of HIV coinfection than those who demonstrated serum anti-HDV antibody negativity. A propensity-matched longitudinal analysis revealed that liver fibrosis (FIB-4 index) progressed more rapidly in patients with positive results for anti-HDV antibody tests. CONCLUSIONS: The recent prevalence of HDV infections in Japanese patients with HBV was 1.7% (10/601). These patients experienced rapid liver fibrosis progression, highlighting the importance of routine HDV testing.

Hepatitis D Virus and HBsAg Dynamics in the era of new Antiviral Treatments.

PURPOSE OF REVIEW: Hepatitis D virus (HDV) infection is the most severe form of chronic viral hepatitis, with no FDA-approved therapy. Progress in the development of effective HDV treatments is accelerating. This review highlights how mathematical modeling is improving understanding of HDV-HBsAg-host dynamics during antiviral therapy and generating insights into the efficacy and modes of action (MOA) of new antiviral agents. RECENT FINDINGS: Clinical trials with pegylated-interferon-λ, bulevertide, nucleic acid polymers, and/or lonafarnib against various steps of the HDV-life cycle have revealed new viral-kinetic patterns that were not observed under standard treatment with pegylated-interferon-α. Modeling indicated that the half-lives of circulating HDV and HBsAg are ~ 1.7 d and ~ 1.3 d, respectively, estimated the relative response of HDV and HBsAg during different antiviral therapies, and provided insights into the efficacy and MOA of drugs in development for treating HDV, which can inform response-guided therapy to individualize treatment duration. Mathematical modeling of HDV and HBsAg kinetics provides a window into the HDV virus lifecycle, HDV-HBsAg-host dynamics during antiviral therapy, and the MOA of new drugs for HDV.

Diagnosis and Management of Hepatitis Delta Virus Infection.

Hepatitis D virus (HDV) depends on hepatitis B virus (HBV) to enter and exit hepatocytes and to replicate. Despite this dependency, HDV can cause severe liver disease. HDV accelerates liver fibrosis, increases the risk of hepatocellular carcinoma, and hastens hepatic decompensation compared to chronic HBV monoinfection. The Chronic Liver Disease Foundation (CLDF) formed an expert panel to publish updated guidelines on the testing, diagnosis, and management of hepatitis delta virus. The panel group performed network data review on the transmission, epidemiology, natural history, and disease sequelae of acute and chronic HDV infection. Based on current available evidence, we provide recommendations for screening, testing, diagnosis, and treatment of hepatitis D infection and review upcoming novel agents that may expand treatment options. The CLDF recommends universal HDV screening for all patients who are Hepatitis B surface antigen-positive. Initial screening should be with an assay to detect antibodies generated against HDV (anti-HDV). Patients who are positive for anti-HDV IgG antibodies should then undergo quantitative HDV RNA testing. We also provide an algorithm that describes CLDF recommendations on the screening, diagnosis, testing, and initial management of Hepatitis D infection.

Hepatitis D virus-induced interferon response and administered interferons control cell division-mediated virus spread.

BACKGROUND & AIMS: Besides HBV-dependent de novo infection, cell division-mediated spread contributes to HDV persistence and dampens the effect of antivirals that abrogate de novo infection. Nonetheless, the combination of these antivirals with interferons (IFNs) showed strong synergism in recent clinical trials, implying a complementary mode-of-action of IFNs. Therefore, we investigated the effect of IFN response on cell division-mediated HDV spread. METHODS: Cells infected with HDV were passaged to undergo cell division. The effect of the IFN response was evaluated by blocking HDV-induced IFN activation, by applying different IFN treatment regimens, and by adjusting HDV infection doses. RESULTS: Cell division-mediated HDV spread was highly efficient following infection of HuH7NTCP cells (defective in IFN production), but profoundly restricted in infected IFN-competent HepaRGNTCP cells. Treatment with IFN-α/-λ1 inhibited HDV spread in dividing HuH7NTCP cells, but exhibited a marginal effect on HDV replication in resting cells. Blocking the HDV-induced IFN response with the JAK1/2 inhibitor ruxolitinib or knocking down MDA5 augmented HDV spread in dividing HepaRGNTCP cells. The virus-induced IFN response also destabilized HDV RNA in dividing cells. Moreover, the effect of exogenous IFNs on cell division-mediated HDV spread was more pronounced at low multiplicities of infection with weak virus-induced IFN responses. CONCLUSIONS: Both HDV-induced IFN response and exogenous IFN treatment suppress cell division-mediated HDV spread, presumably through acceleration of HDV RNA decay. Our findings demonstrate a novel mode-of-action of IFN, explain the more pronounced effect of IFN therapy in patients with lower HDV serum RNA levels, and provide insights for the development of combination therapies. LAY SUMMARY: Chronic hepatitis D is a major health problem. The causative pathogen hepatitis D virus (HDV) can propagate through viral particle-mediated infection and the division of infected cells. Although viral particle-dependent infection can be blocked by recently developed drugs, therapies addressing the cell division route have not been reported. Taking advantage of relevant cell culture models, we demonstrate that the widely used immune modulator interferon can efficiently suppress HDV spread through cell division. This work unveils a new function of interferon and sheds light on potentially curative combination therapies.

Bulevirtide with or without pegIFNα for patients with compensated chronic hepatitis delta: From clinical trials to real-world studies.

Chronic hepatitis D (CHD) is the most severe form of viral hepatitis, characterised by the greatest increase in risk of cirrhosis, hepatic decompensation and hepatocellular carcinoma. Pegylated-interferon-α (pegIFNα), the only off-label therapeutic option, has been available for the last 30 years but is associated with suboptimal response rates and poor tolerability. Among the new treatment strategies under clinical evaluation, the entry inhibitor bulevirtide (BLV) is the only one that has received conditional approval from the European Medicines Agency (EMA); approval was granted in July 2020 for the treatment of adult patients with compensated CHD at a dose of 2 mg daily. Phase II studies and the week 24 interim analysis of a phase III study demonstrated the efficacy and safety of this treatment as a monotherapy or combined with pegIFNα. This favourable profile has been confirmed by recent real-world studies performed in Europe. As a long-term monotherapy, BLV has been successfully used to treat patients with advanced compensated cirrhosis. These encouraging yet preliminary findings must be viewed with caution as many critical issues related to this new antiviral strategy are still poorly understood, as summarised in this review. While waiting for new anti-HBV and anti-HDV drugs to become available for combination studies, BLV treatment is currently the only available anti-HDV therapeutic option that might improve the long-term prognosis of difficult-to-manage patients with CHD.

Evaluation of dried blood spots for hepatitis B and D serology and nucleic acid testing.

Areas with the highest burden of hepatitis B virus (HBV) infection are often low-middle-income countries with limited access to diagnosis due to isolation, affordability, and/or feasibility. Dried blood spots (DBSs) provide an alternative for remote areas where collection and transportation of serum is impractical. In this study, the application of DBS for serological and molecular detection of HBV and hepatitis D virus (HDV) was evaluated. Hepatitis B surface antigen was detected in 87 of 91 (95.6%) DBS. Seventeen of 21 (81%) had detectable HBeAg and 52 of 71 (73.2%) were anti-HBe positive. Anti-HD was detectable in 11 of 12 (91.6%) spiked control DBS after an initial failure to detect in patient DBS. HBV DNA was detected from 50 of 70 (71.4%) DBS with serum loads greater than 200 IU/mL in an in-house assay and 18 of 24 (75%) DBS with loads exceeding 389 IU/mL in a commercial assay. Using linear regression, HBV DNA loads from DBS were able to predict serum loads in 46 of 50 (92%) samples to within 1 log of actual serum load. HDV RNA was detected in 42 of 47 (89%) DBS with serum levels greater than 7200 IU/mL. DBSs are recommended for diagnosis of HBV, monitoring, and detection of high loads in pregnant women where peripheral blood testing remains unfeasible. Detection of HDV RNA from DBS may prove useful in endemic areas.