Bioequivalence Study of Velpatasvir/Sofosbuvir Oral Coated Tablets in Healthy Volunteers Under Fasting Conditions

This study was conducted as a single-site, open-label, randomized, replicated crossover trial with 4 treatment periods. The aim was to evaluate the bioequivalence of a generic test drug containing velpatasvir and sofosbuvir compared to an established brand-name medication in healthy White subjects under fasting conditions. Blood samples were collected at specified intervals up to 72 hours after dosing to measure the concentrations of velpatasvir and sofosbuvir using a certified high-performance liquid chromatography with tandem mass spectrometry method. The bioequivalence of the 2 formulations was confirmed when statistical analysis showed that confidence intervals for the log-transformed peak concentration and area under the concentration-time curve from time 0 to the last quantifiable sample were within an acceptable range from 80% to 125%. Criteria for bioequivalence were met for both area under the concentration-time curve from time 0 until the last quantifiable sample and peak concentration parameters. No adverse effects were reported during this trial in both groups.

Hepatitis C virus subtype distribution and resistance-associated substitutions in high-risk population groups in Guangdong Province, China

OBJECTIVE

In Guangdong Province, hepatitis C virus (HCV) had been found to confer resistance to direct-acting antivirals (DAAs). There were few studies of HCV subtypes and resistance-associated substitutions (RASs) of HCV in different high-risk populations. In this study, we aimed to determine the subtype distribution and the RASs in high-risk population groups, including drug users (DU), men who have sex with men (MSM), female sex workers (FSW), and male patients with sexually transmitted diseases (STD) in Guangdong Province (a highly developed province with a large population).

METHODS

Using a city-based sampling strategy,1356 samples were obtained from different population groups. Phylogenetic analyses determined subtypes based on Core, NS5B, or NS5A sequences. HCV subtype distribution and RASs in various risk groups and regions were analyzed.

RESULTS

Ten subtypes, of which 6 h and 6 k were novel in Guangdong, were identified. The primary subtype among all risk groups was 6a. RASs in 1b and 3a were different from those observed in other studies. Subtype 3b in western Guangdong was higher than the other three regions. No RASs were found in 6a or any other genotype 6.

CONCLUSIONS

The HCV subtypes are expanding in high-risk populations in Guangdong. Drug use by other risk groups and commercial sex by DU may bridge the dissemination of 6a from DU to other populations. The RAS profiles of 1b and 3a differed from those reported in studies conducted in southwestern China. Further research is required to determine the reason for this discrepancy. Moreover, the combination of RASs was high in subtype 3b. To guide HCV treatment of subtype 3b, pretreatment subtyping of HCV genotype 3 should be considered in western cities in the near future.

Is there still hope for the prophylactic hepatitis C vaccine? A review of different approaches

Despite remarkable progress in the treatment of hepatitis C virus (HCV) infection, it remains a significant global health burden, necessitating the development of an effective prophylactic vaccine. This review paper presents the current landscape of HCV vaccine candidates and approaches, including more traditional, based on inactivated virus, and more modern, such as subunit protein, vectored, based on nucleic acids (DNA and mRNA) and virus-like particles. The concept of the HCV vaccine is first put in the context of viral genetic diversity and adaptive responses to HCV infection, an understanding of which is crucial in guiding the development of an effective vaccine against such a complex virus. Because ethical dimensions are also significant in vaccine research, development, and potential deployment, we also address them in this paper. The road to a safe and effective vaccine to prevent HCV infection remains bumpy due to the genetic variation of HCV and its ability to evade immune responses. The progress in cell-culture systems allowed for the production of an inactivated HCV vaccine candidate, which can induce cross-neutralizing antibodies in vitro, but whether this could prevent infection in humans is unknown. Subunit protein vaccine candidates that entered clinical trials elicited HCV-specific humoral and cellular responses, though it remains to be shown whether they translate into effective prevention of HCV infection or progression of infection to a chronic state. Such responses were also induced by a clinically tested vector-based vaccine candidate, which decreased the viral HCV load but did not prevent chronic HCV infection. These disappointments were not readily predicted from preclinical animal studies. The vaccine platforms employing virus-like particles, DNA, and mRNA provide opportunities for the HCV vaccine, but their potential in this context has yet to be shown. Ensuring the designed vaccine is based on conserved epitope(s) and elicits broadly neutralizing immune responses is also essential. Given failures in developing a prophylactic HCV vaccine, it is crucial to continue supporting national strategies, including funding for screening and treatment programs. However, these actions are likely insufficient to permanently control the HCV burden, encouraging further mobilization of significant resources for HCV vaccine research as a missing element in the elimination of viral hepatitis as a global public health.

The prevalence of hepatitis C virus genotypes and factors associated with cirrhosis, fatty liver, and viral load: A registry-based cross-sectional cohort study in Western Iran during 1999-2023

Background and Aims

Hepatitis C virus (HCV) is an important infectious disease that imposes a significant burden on healthcare systems. Determining the prevalence of HCV genotypes in a area is essential for the successful implementation of HCV elimination programs and allocation of financial resources to direct-acting antiviral direct-acting antivirals (DAA) treatments against prevalent HCV genotypes. Accordingly, we conducted a registry-based cross-sectional cohort study to investigate the prevalence of HCV genotypes and factors associated with cirrhosis, fatty liver, and viral load in Kermanshah Province, Western Iran.

Methods

Patients presenting to the Hepatitis Clinic of the Research Center for Infectious Diseases affiliated with Kermanshah University of Medical Sciences between 1999 and 2023 were enrolled in this study. Serum samples were collected to assess HCV genotypes and viral load. Additionally, demographic data and the status of cirrhosis and fatty liver were extracted from the registry system records throughout the study period.

Results

Records of 828 patients with an average age of 40.38 ± 11.72 years (range: 11-80 years) were included in the study that 721 individuals were male, and 107 were female. The prevalence of fatty liver and cirrhosis was 30.3% and 12.9%, respectively. Four genotypes (1, 2, 3, and 4) and four subtypes (1a, 1b, 3a, and 3b) were identified, with subtype 3a (55.7%) being the most prevalent, followed by subtype 1a (34.3%). None of the variables including age, gender, viral load level, and genotypes 1 and 3 were associated with fatty liver or cirrhosis. However, age, gender, and genotype were correlated with the viral load (p ≤ 0.05).

Conclusion

The most common HCV subtypes in Kermanshah were 3a and 1a. Genotypes 2 and 4 were identified in one case each. Further studies on identifying HCV subtypes in different regions of the country are recommended to manage HCV infection and predict the prognosis.

Genetic history of hepatitis C virus genotype 6 in Taiwan

Unlike hepatitis C virus (HCV) genotype (GT) 6, which is widely circulated in Southeast Asia and South China, GT 6 was not reported in Taiwan until 2006. GT 1b and 2a, also known as global HCV subtypes, have been reported as major GTs circulating in Taiwan. Because of improvement in genotyping kits and sequencing techniques for the subtyping of HCV, an increasing number of GT 6 subtypes have been reported, especially subtype 6a among intravenous drug users with human immunodeficiency virus infection after an outbreak since 2003. Thus, HCV GT 6 infection is regarded to be closely associated with injection drug use. However, recently, we found an unexpectedly high GT 6 prevalence in the general population in Tainan, southern Taiwan. Most of these GT 6 samples belonged to a putative novel subtype closely related to 6g and 6w instead of 6a. Phylogenetic analyses indicated that this putative 6g-related novel subtype and 6w could be indigenous in southern Taiwan for centuries. Southern Taiwan could be the origin of HCV subtype 6w. This finding might change the perspective of HCV epidemiology in Taiwan.

Like a Rolling Stone? A Review on Spontaneous Clearance of Hepatitis C Virus Infection

Elimination of hepatitis C virus (HCV) without the need for medical intervention, known as spontaneous clearance (SC), occurs at a significantly lower rate than in the case of hepatitis B virus infection and only in selected individuals, such as reportedly in Keith Richards, a guitarist of The Rolling Stones. The present paper provides an updated narrative review of the research devoted to the phenomenon in order to identify and discuss the demographic, lifestyle-related, clinical, viral genotype-related, and host genetic factors underpinning the SC occurrence. The body of evidence indicates that the likelihood of SC is decreased in older individuals, men, Black people, HIV-coinfected subjects, and intravenous drug and alcohol users. In turn, HBV coinfection and specific polymorphism of the genes encoding interferon lambda 3 (particularly at rs8099917) and interferon lambda 4 (particularly at rs12979860) and HLA genes increase the odds of SC. Numerous other host-specific genetic factors could be implicated in SC, but the evidence is limited only to certain ethnic groups and often does not account for confounding variables. SC of HCV infection is a complex process arising from a combination of various factors, though a genetic component may play a leading role in some cases. Understanding factors influencing the likelihood of this phenomenon justifies better surveillance of high-risk groups, decreasing health inequities in particular ethnic groups, and may guide the development of a prophylactic vaccine, which at present is not available, or novel therapeutic strategies. Further research is needed to elucidate the exact mechanisms underlying SC and to explore potential interventions that could enhance this natural antiviral response.

Update on Hepatitis C Vaccine: Results and Challenges

Therapy against the Hepatitis C virus (HCV) has significantly improved with the introduction of direct-acting antiviral drugs (DAAs), achieving over 95% sustained virological response (SVR). Despite this, the development of an effective anti-HCV vaccine remains a critical challenge due to the low number of patients treated with DAAs and the occurrence of HCV reinfections in high-risk groups. Current vaccine strategies aim to stimulate either B-cell or T-cell responses. Vaccines based on E1 and E2 proteins can elicit broad cross-neutralizing antibodies against all major HCV genotypes, though with varying efficiencies and without full protection against infection. In humans, the neutralizing antibodies induced by such vaccines mainly target the AR3 region, but their levels are generally insufficient for broad neutralization. Various HCV proteins expressed through different viral vectors have been utilized to elicit T cell immune responses, showing sustained expansion of HCV-specific effector memory T cells and improved proliferation and polyfunctionality of memory T cells over time. However, despite these advancements, the frequency and effectiveness of T-cell responses remain limited.

Effect of immunogenetics polymorphism and expression on direct-acting antiviral drug response in chronic hepatitis C

The prevalence of HCV infection in Egypt has decreased following the introduction of direct-acting antiviral therapy. However, treatment response is influenced by various factors, particularly host immunogenetics such as IL-28B and FOXP3 polymorphisms. The current study examined the impact of SNPs in the FOXP3 gene promoter region on HCV-infected Egyptian patients, along with SNPs in the IL28B gene.This study involved 99 HCV patients who achieved SVR12 after a 12 week DAA treatment while 63 HCV patients experienced treatment failure. IL28B rs12979860 SNP was identified using real-time PCR, while IL28B rs8099917, FOXP3 rs3761548, and rs2232365 SNPs were analyzed using RFLP-PCR. Serum levels of IL28B and FOXP3 were quantified using ELISA technique in representative samples from both groups. The IL28B rs12979860 T > C (P = 0.013) and FOXP3 rs2232365 A > G polymorphisms (P = 0.008) were found to significantly increase the risk of non-response. Responders had higher IL28B serum levels (P = 0.046) and lower FOXP3 levels (P < 0.001) compared to non-responders. Regression analysis showed an association between IL28B rs12979860 and FOXP3 rs2232365 with treatment response, independent of age and gender. A predictive model was developed with 76.2% sensitivity and 91.9% specificity for estimating DAAs response in HCV patients.Our findings confirmed the IL28B rs12979860 T > C and FOXP3 rs2232365 A > G polymorphisms significantly affect DAA treatment response in HCV Egyptian patients. Lower levels of IL-28B along with higher levels of FOXP3 are linked to poor response. Our results may lead to new insights into DAA responsiveness contributing to personalized medicine and improving therapeutic decision-making for HCV patients.

'Unusual' HCV genotype subtypes: origin, distribution, sensitivity to direct-acting antiviral drugs and behaviour on antiviral treatment and retreatment

The high genetic diversity of hepatitis C virus (HCV) has led to the emergence of eight genotypes and a large number of subtypes in limited geographical areas. Currently approved pangenotypic DAA regimens have been designed and developed to be effective against the most common subtypes (1a, 1b, 2a, 2b, 2c, 3a, 4a, 5a and 6a). However, large populations living in Africa and Asia, or who have migrated from these regions to industrialised countries, are infected with 'unusual', non-epidemic HCV subtypes, including some that are inherently resistant to currently available direct-acting antiviral (DAA) drugs due to the presence of natural polymorphisms at resistance-associated substitution positions. In this review article, we describe the origin and subsequent global spread of HCV genotypes and subtypes, the current global distribution of common and unusual HCV subtypes, the polymorphisms naturally present in the genome sequences of unusual HCV subtypes that may confer inherently reduced susceptibility to DAA drugs and the available data on the response of unusual HCV subtypes to first-line HCV therapy and retreatment. We conclude that the problem of unusual HCV subtypes that are inherently resistant to DAAs and its threat to the global efforts to eliminate viral hepatitis are largely underestimated and warrant vigorous action.

Exploring T-Cell Immunity to Hepatitis C Virus: Insights from Different Vaccine and Antigen Presentation Strategies

The hepatitis C virus (HCV) is responsible for approximately 50 million infections worldwide. Effective drug treatments while available face access barriers, and vaccine development is hampered by viral hypervariability and immune evasion mechanisms. The CD4+ and CD8+ T-cell responses targeting HCV non-structural (NS) proteins have shown a role in the viral clearance. In this paper, we reviewed the studies exploring the relationship between HCV structural and NS proteins and their effects in contributing to the elicitation of an effective T-cell immune response. The use of different vaccine platforms, such as viral vectors and virus-like particles, underscores their versability and efficacy for vaccine development. Diverse HCV antigens demonstrated immunogenicity, eliciting a robust immune response, positioning them as promising vaccine candidates for protein/peptide-, DNA-, or RNA-based vaccines. Moreover, adjuvant selection plays a pivotal role in modulating the immune response. This review emphasizes the importance of HCV proteins and vaccination strategies in vaccine development. In particular, the NS proteins are the main focus, given their pivotal role in T-cell-mediated immunity and their sequence conservation, making them valuable vaccine targets.

Pharmacophore-Assisted Covalent Docking Identifies a Potential Covalent Inhibitor for Drug-Resistant Genotype 3 Variants of Hepatitis C Viral NS3/4A Serine Protease

The emergence of drug-resistance-inducing mutations in Hepatitis C virus (HCV) coupled with genotypic heterogeneity has made targeting NS3/4A serine protease difficult. In this work, we investigated the mutagenic variations in the binding pocket of Genotype 3 (G3) HCV NS3/4A and evaluated ligands for efficacious inhibition. We report mutations at 14 positions within the ligand-binding residues of HCV NS3/4A, including H57R and S139P within the catalytic triad. We then modelled each mutational variant for pharmacophore-based virtual screening (PBVS) followed by covalent docking towards identifying a potential covalent inhibitor, i.e., cpd-217. The binding stability of cpd-217 was then supported by molecular dynamic simulation followed by MM/GBSA binding free energy calculation. The free energy decomposition analysis indicated that the resistant mutants alter the HCV NS3/4A-ligand interaction, resulting in unbalanced energy distribution within the binding site, leading to drug resistance. Cpd-217 was identified as interacting with all NS3/4A G3 variants with significant covalent docking scores. In conclusion, cpd-217 emerges as a potential inhibitor of HCV NS3/4A G3 variants that warrants further in vitro and in vivo studies. This study provides a theoretical foundation for drug design and development targeting HCV G3 NS3/4A.

The association between serum vitamin A concentrations and virus hepatitis among U.S. adults from the NHANES database: a cross-sectional study

Objective

According to the present study, the relationship between vitamin A (VA) levels and hepatitis virus carriage has been unclear and controversial. This study aimed to determine the potential relationship between serum VA levels and viral hepatitis and to provide ideas for future clinical treatments.

Methods

A cross-sectional study was performed using the 2005-2006 and 2017-2018 National Health and Nutrition Examination Survey (NHANES) datasets. Multiple linear regression and logistic regression were adopted to analyze the association between serological hepatitis B surface antigen (HBsAg) or hepatitis C RNA (HCV-RNA) positivity and VA levels. There were 5,351 HBsAg-related responders and 242 HCV-RNA-related responders, including 52 HBsAg (+) and 104 HCV-RNA (+) responders.

Results

Compared with HBsAg (-) and HCV-RNA (-) respondents, HBsAg (+) and HCV-RNA (+) respondents tended to have lower serum VA levels, respectively [1.63 (1.33 ~ 2.01) vs. 1.92 (1.57 ~ 2.34), P < 0.001; 1.54 (1.25 ~ 1.83) vs. 1.78 (1.46 ~ 2.26), P < 0.001]. A greater percentage of responders in the subclinical VA deficiency (SVAD) group were HBsAg (+) and HCV-RNA (+) than were those in the normal VA (VAN) group [2.4% (9/374) vs. 0.9% (43/4977), p = 0.003; 61.5% (16/26) vs. 40.7% (88/215), p = 0.043]. According to the results of the multiple regression analyses of the different models, the serum VA concentration was negatively correlated with HBsAg (+) and HCV-RNA (+) status (β = -0.14, 95% CI = -0.30 to -0.01, p = 0.066; β = -0.29, 95% CI = -0.50 ~ -0.09, p = 0.005, respectively). Compared to those with SVAD, patients with VAN were less likely to be serologically HBsAg (+) or HCV-RNA (+) (OR = 0.53, 95% CI = 0.25 ~ 1.10, p = 0.089; OR = 0.39, 95% CI = 0.18 ~ 0.84, p = 0.016, respectively).

Conclusion

Our study provides evidence that patients who are HBsAg (+) or HCV-RNA (+) have a high incidence of SVAD. Moreover, HBsAg and HCV-RNA positivity are negatively correlated with VA levels, and patients with SVAD are more likely to carry HBsAg (+) or HCV-RNA (+). These findings suggest that the relationship between hepatitis viruses and vitamin A needs to be validated by more basic studies and clinical large-sample randomized controlled trials to provide ideas for new therapeutic targets.

Distinct Characteristic Binding Modes of Benzofuran Core Inhibitors to Diverse Genotypes of Hepatitis C Virus NS5B Polymerase: A Molecular Simulation Study

The benzofuran core inhibitors HCV-796, BMS-929075, MK-8876, compound 2, and compound 9B exhibit good pan-genotypic activity against various genotypes of NS5B polymerase. To elucidate their mechanism of action, multiple molecular simulation methods were used to investigate the complex systems of these inhibitors binding to GT1a, 1b, 2a, and 2b NS5B polymerases. The calculation results indicated that these five inhibitors can not only interact with the residues in the palm II subdomain of NS5B polymerase, but also with the residues in the palm I subdomain or the palm I/III overlap region. Interestingly, the binding of inhibitors with longer substituents at the C5 position (BMS-929075, MK-8876, compound 2, and compound 9B) to the GT1a and 2b NS5B polymerases exhibits different binding patterns compared to the binding to the GT1b and 2a NS5B polymerases. The interactions between the para-fluorophenyl groups at the C2 positions of the inhibitors and the residues at the binding pockets, together with the interactions between the substituents at the C5 positions and the residues at the reverse β-fold (residues 441-456), play a key role in recognition and the induction of the binding. The relevant studies could provide valuable information for further research and development of novel anti-HCV benzofuran core pan-genotypic inhibitors.

Recombinant H77C gpE1/gpE2 heterodimer elicits superior HCV cross-neutralisation than H77C gpE2 alone

BACKGROUND & AIMS

An optimal HCV vaccine requires the induction of antibodies that neutralise the infectivity of many heterogenous viral isolates. In this study, we have focused on determining the optimal recombinant envelope glycoprotein component to elicit cross-neutralising antibodies against global HCV genotypes. We compared the immunoreactivity and antigenicity of the HCV genotype 1a strain H77C-derived envelope glycoprotein heterodimer gpE1/gpE2 with that of recombinant gpE2 alone.

METHODS

Characterisation of the envelope glycoproteins was accomplished by determining their ability to bind to a panel of broadly cross-neutralising monoclonal antibodies. Immunogenicity was determined by testing the ability of vaccine antisera to neutralise the infectivity in vitro of a panel of pseudotyped HCV particles in which gpE1/gpE2 derived from representative isolates of the major global HCV genotypes were displayed.

RESULTS

gpE1/gpE2 binds to more diverse broadly cross-neutralising antibodies than gpE2 alone and elicits a broader profile of cross-neutralising antibodies in animals, especially against more heterologous, non-1a genotypes. While not all heterologous HCV strains can be potently inhibited in vitro by gpE1/gpE2 antisera derived from a single HCV strain, the breadth of heterologous cross-neutralisation is shown to be substantial.

CONCLUSIONS

Our work supports the inclusion of gpE1/gpE2 in an HCV vaccine in order to maximise the cross-neutralisation of heterogenous HCV isolates. Our data also offers future directions in formulating a cocktail of gpE1/gpE2 antigens from a small selection of HCV genotypes to further enhance cross-neutralisation of global HCV strains and hopefully advance the development of a globally effective HCV vaccine.

IMPACT AND IMPLICATIONS

An HCV vaccine is urgently required to prevent the high global incidence of HCV infection and disease. Since HCV is a highly heterogeneous virus, it is desirable for a vaccine to elicit antibodies that neutralise the infectivity of most global strains. To this end, we have compared the immunoreactivity and antigenicity of recombinant H77C E1E2 heterodimer with that of H77C E2 alone and show that the former exhibits more cross-neutralising epitopes and demonstrates a broader cross-neutralisation profile in vitro. In addition, our data suggests a way to further broaden cross-neutralisation using a combination of E1E2 antigens derived from a few different HCV clades. Our work is relevant for the development of an effective global HCV vaccine.

Comprehensive survey of conserved RNA secondary structures in full-genome alignment of Hepatitis C virus

Hepatitis C virus (HCV) is a plus-stranded RNA virus that often chronically infects liver hepatocytes and causes liver cirrhosis and cancer. These viruses replicate their genomes employing error-prone replicases. Thereby, they routinely generate a large 'cloud' of RNA genomes (quasispecies) which-by trial and error-comprehensively explore the sequence space available for functional RNA genomes that maintain the ability for efficient replication and immune escape. In this context, it is important to identify which RNA secondary structures in the sequence space of the HCV genome are conserved, likely due to functional requirements. Here, we provide the first genome-wide multiple sequence alignment (MSA) with the prediction of RNA secondary structures throughout all representative full-length HCV genomes. We selected 57 representative genomes by clustering all complete HCV genomes from the BV-BRC database based on k-mer distributions and dimension reduction and adding RefSeq sequences. We include annotations of previously recognized features for easy comparison to other studies. Our results indicate that mainly the core coding region, the C-terminal NS5A region, and the NS5B region contain secondary structure elements that are conserved beyond coding sequence requirements, indicating functionality on the RNA level. In contrast, the genome regions in between contain less highly conserved structures. The results provide a complete description of all conserved RNA secondary structures and make clear that functionally important RNA secondary structures are present in certain HCV genome regions but are largely absent from other regions. Full-genome alignments of all branches of Hepacivirus C are provided in the supplement.

Contemporary Insights into Hepatitis C Virus: A Comprehensive Review

Hepatitis C virus (HCV) remains a significant global health challenge. Approximately 50 million people were living with chronic hepatitis C based on the World Health Organization as of 2024, contributing extensively to global morbidity and mortality. The advent and approval of several direct-acting antiviral (DAA) regimens significantly improved HCV treatment, offering potentially high rates of cure for chronic hepatitis C. However, the promising aim of eventual HCV eradication remains challenging. Key challenges include the variability in DAA access across different regions, slightly variable response rates to DAAs across diverse patient populations and HCV genotypes/subtypes, and the emergence of resistance-associated substitutions (RASs), potentially conferring resistance to DAAs. Therefore, periodic reassessment of current HCV knowledge is needed. An up-to-date review on HCV is also necessitated based on the observed shifts in HCV epidemiological trends, continuous development and approval of therapeutic strategies, and changes in public health policies. Thus, the current comprehensive review aimed to integrate the latest knowledge on the epidemiology, pathophysiology, diagnostic approaches, treatment options and preventive strategies for HCV, with a particular focus on the current challenges associated with RASs and ongoing efforts in vaccine development. This review sought to provide healthcare professionals, researchers, and policymakers with the necessary insights to address the HCV burden more effectively. We aimed to highlight the progress made in managing and preventing HCV infection and to highlight the persistent barriers challenging the prevention of HCV infection. The overarching goal was to align with global health objectives towards reducing the burden of chronic hepatitis, aiming for its eventual elimination as a public health threat by 2030.

Identification of two novel subtypes of hepatitis C virus genotype 8 and a potential new genotype successfully treated with direct acting antivirals

BACKGROUND

Hepatitis C virus (HCV) has a high genetic diversity and is classified into 8 genotypes and over 90 subtypes with some endemic to specific world regions. This could compromise direct-acting antiviral (DAA) efficacy and global HCV elimination.

METHODS

We characterised HCV subtypes 'rare' to the UK (non-1a/1b/2b/3a/4d) by whole genome sequencing via a national surveillance programme. Genetic analyses to determine the genotype of samples with unresolved genotypes were undertaken by comparison with ICTV HCV reference sequences.

RESULTS

Two HCV variants were characterised as being closely related to the recently identified genotype 8 (GT8), with >85% pairwise genetic distance similarity to GT8 sequences and within the typical inter-subtype genetic distance range. The individuals infected by the variants were UK residents originally from Pakistan and India. In contrast, a third variant was only confidently identified to be more similar to GT6 compared to other genotypes across 6% of the genome and was isolated from a UK resident originally from Guyana. All three were cured with pangenotypic DAAs (Sofosbuvir + Velpatasvir or Glecaprevir + Pibrentasvir) despite the presence of resistance polymorphisms in NS3 (80 K/168E), NS5A (28 V/30S/62L/92S/93S) and NS5B (159F).

CONCLUSIONS

This study expands our knowledge of HCV diversity by identifying two new GT8 subtypes and potentially a new genotype.

Viral Hepatitis C: From Unraveling the Nature of Disease to Cure and Global Elimination

BACKGROUND

The discovery of the hepatitis C virus (HCV) and direct-acting antiviral (DAA) drugs is one of the major milestones in the last 3 decades of medicine. These discoveries encouraged the World Health Organization (WHO) to set an ambitious goal to eliminate HCV by 2030, meaning "a 90% reduction in new cases of chronic HCV, a 65% reduction in HCV deaths, and treatment of 80% of eligible people with HCV infections."

SUMMARY

This review summarizes the key achievements from the discovery of HCV to the development of effective treatment and global elimination strategies. A better understanding of HCV structure, enzymes, and lifecycle led to the introduction of new drug targets and the discovery of DAA. Massive public health interventions are required, such as screening, access to care, treatment, and post-care follow-up, to make the most of DAA's potential. Screening must be supported by fast, accessible, sensitive, specific HCV diagnostic tests and noninvasive methods to determine the stage of liver disease. Linkage to care and treatment access are critical components of a comprehensive HCV elimination program, and decentralization plays a key role in ensuring their effectiveness.

KEY MESSAGES

Effective and simple screening strategies, rapid diagnostic tools, linkage to health care, and accessible treatment are key elements to achieving the WHO's goal. Incorporating treatment as prevention strategies into elimination programs together with preventive education and harm reduction interventions can have a profound and lasting impact on reducing both the incidence and prevalence of HCV. However, WHO's goal can be challenging to implement because of the need for high financial resources and strong political commitment.

In silico design of a novel multi-epitope vaccine against HCV infection through immunoinformatics approaches

Infection with the hepatitis C virus (HCV) is one of the causes of liver cancer, which is the world's sixth most prevalent and third most lethal cancer. The current treatments do not prevent reinfection; because they are expensive, their usage is limited to developed nations. Therefore, a prophylactic vaccine is essential to control this virus. Hence, in this study, an immunoinformatics method was applied to design a multi-epitope vaccine against HCV. The best B- and T-cell epitopes from conserved regions of the E2 protein of seven HCV genotypes were joined with the appropriate linkers to design a multi-epitope vaccine. In addition, cholera enterotoxin subunit B (CtxB) was included as an adjuvant in the vaccine construct. This study is the first to present this epitopes-adjuvant combination. The vaccine had acceptable physicochemical characteristics. The vaccine's 3D structure was predicted and validated. The vaccine's binding stability with Toll-like receptor 2 (TLR2) and TLR4 was confirmed using molecular docking and molecular dynamics (MD) simulation. The immune simulation revealed the vaccine's efficacy by increasing the population of B and T cells in response to vaccination. In silico expression in Escherichia coli (E. coli) was also successful.

Comparison of diagnostic performance among Abbott RealTime HCV Genotyping II, Abbott HCV Genotype plus RUO, and Roche Cobas HCV Genotyping assays for hepatitis C virus genotyping

Comparison of diagnostic accuracy for commercial hepatitis C virus (HCV) genotyping (Abbott RealTime HCV Genotyping II, Roche Cobas Genotyping) and investigational Abbott HCV Genotype plus RUO assays designed to discriminate genotype (GT)-1a, 1b or 6 in cases of ambiguous GT from the Abbott commercial assay remains limited. 743 HCV-viremic samples were subjected to analysis using Abbott and Roche commercial as well as Abbott HCV Genotype plus RUO assays. Next-generation sequencing (NGS) targeting core region was employed as the reference standard. Diagnostic accuracy was reported as the number of participants (percentages) along with 95% confidence intervals (CIs). Using NGS, 741 samples (99.7%) yielded valid genotyping results. The diagnostic accuracies were 97.6% (95% CI: 96.1%-98.5%) and 95.3% (95% CI: 93.4%-96.6%) using Abbott and Roche commercial assays (p = 0.0174). Abbott commercial assay accurately diagnosed HCV GT-6a and 6w, whereas Roche commercial assay accurately diagnosed HCV GT-6a. Both assays demonstrated low accuracies for HCV GT-6b, 6e, 6g, and 6n. Abbott HCV Genotype plus RUO assay discriminated 13 of the 14 samples (92.9%; 95% CI: 64.2%-99.6%) that yielded ambiguous GT. Both assays were capable of diagnosing mixed HCV infections when the minor genotype comprised >8.4% of the viral load. The diagnostic performance of commercial HCV genotyping assays is commendable. Abbott assay demonstrated superior performance compared to Roche assay in diagnosing HCV GT-6. Abbott HCV Genotype plus RUO assay aids in discriminating ambiguous GT. Both commercial assays are proficient in diagnosing mixed HCV infections at a cut-off viral load of 8.4% in minor genotype.

Epidemiology of Hepatitis C Virus in HIV Patients from West Mexico: Implications for Controlling and Preventing Viral Hepatitis

The complex epidemiology of hepatitis C virus (HCV) infection among human immunodeficiency virus (HIV) patients in West Mexico remains poorly understood. Thus, this study aimed to investigate the HCV prevalence, HCV-associated risk factors, and HCV genotypes/subtypes and assess their impacts on liver fibrosis in 294 HIV patients (median age: 38 years; 88.1% male). HCV RNA was extracted and amplified by PCR. Hepatic fibrosis was assessed using three noninvasive methods: transient elastography (TE), the aspartate aminotransferase (AST)-to-platelets ratio index score (APRI), and the fibrosis-4 score (FIB4). Patients with liver stiffness of ≥9.3 Kpa were considered to have advanced liver fibrosis. HCV genotypes/subtypes were determined by line probe assay (LiPA) or Sanger sequencing. The prevalence of HIV/HCV infection was 36.4% and was associated with injection drug use (odds ratio (OR) = 13.2; 95% confidence interval (CI) = 5.9-33.6; p < 0.001), imprisonment (OR = 3.0; 95% CI = 1.7-5.4; p < 0.001), the onset of sexual life (OR = 2.6; 95% CI = 1.5-4.5; p < 0.001), blood transfusion (OR = 2.5; 95% CI = 1.5-4.2; p = 0.001), tattooing (OR = 2.4; 95% CI = 1.4-3.9; p = 0.001), being a sex worker (OR = 2.3; 95% CI = 1.0-5.4; p = 0.046), and surgery (OR = 1.7; 95% CI = 1.0-2.7; p = 0.042). The HCV subtype distribution was 68.2% for 1a, 15.2% for 3a, 10.6% for 1b, 3.0% for 2b, 1.5% for 2a, and 1.5% for 4a. The advanced liver fibrosis prevalence was highest in patients with HIV/HCV co-infection (47.7%), especially in those with HCV subtype 1a. CD4+ counts, albumin, direct bilirubin, and indirect bilirubin were associated with liver fibrosis. In conclusion, HCV infection had a significant impact on the liver health of Mexican HIV patients, highlighting the need for targeted preventive strategies in this population.

JFH1-based Core-NS2 genotype variants of HCV with genetic stability in vivo and in vitro: Important tools in the evaluation of virus neutralization

BACKGROUND AND AIMS

HCV infection continues to be a major global health burden despite effective antiviral treatments. The urgent need for a protective vaccine is hindered by the scarcity of suitable HCV-permissive animal models tractable in vaccination and challenge studies. Currently, only antibody neutralization studies in infectious cell culture systems or studies of protection by passive immunization of human liver chimeric mice offer the possibility to evaluate the effect of vaccine-induced antibodies. However, differences between culture-permissive and in vivo-permissive viruses make it a challenge to compare analyses between platforms. To address this problem, we aimed at developing genotype-specific virus variants with genetic stability both in vitro and in vivo.

APPROACH AND RESULTS

We demonstrated infection of human liver chimeric mice with cell culture-adapted HCV JFH1-based Core-NS2 recombinants of genotype 1-6, with a panel of 10 virus strains used extensively in neutralization and receptor studies. Clonal re-engineering of mouse-selected mutations resulted in virus variants with robust replication both in Huh7.5 cells and human liver chimeric mice, with genetic stability. Furthermore, we showed that, overall, these virus variants have similar in vitro neutralization profiles as their parent strains and demonstrated their use for in vivo neutralization studies.

CONCLUSIONS

These mouse-selected HCV recombinants enable the triage of new vaccine-relevant antibodies in vitro and further allow characterization of protection from infection in vivo using identical viruses in human liver chimeric mice. As such, these viruses will serve as important resources in testing novel antibodies and can thus guide strategies to develop an efficient protective vaccine against HCV infection.

Molecular characterization of the nonstructural 5A (NS5A) region of hepatitis C virus in Thai blood donors

Direct acting antivirals (DAAs) have been developed for hepatitis C virus (HCV) therapy, and they are usually effective, however resistance to DAA regimens has also been reported to have a significant impact. Resistance associated substitutions (RASs) in the NS5A region are known to be correlated with failure of DAA therapy. HCV genotypes 3a and 1 are the most prevalent genotypes in Thailand. This study analyzed the type and frequency of RASs associated with DAA failure, focusing on the NS5A region. Serum samples of HCV genotype 3a, 1a, and 1b infection from Thai blood donors were selected. The NS5A region was amplified using reverse transcription-polymerase chain reaction (RT-PCR). A phylogenetic tree was constructed to identify the genotypes of HCV. Nucleotide sequencing and amino acid sequencing were conducted to determine the prevalence of RASs. Construction of the phylogenetic tree indicated that 29 samples were genotype 3a, 11 samples were genotype 1a, and 9 were genotype 1b. Both HCV genotypes 1a and 3a can be categorized into two subclades. Results showed that the NS5A substitutions A30V/K, A62T/V/I/M/P/S/L, and S98G were present in HCV genotype 3a. In HCV genotype 1a, only NS5A RASs H54Y was detected. NS5A amino acid substitutions Q54H and P58L were found in HCV genotype 1b. In conclusion, NS5A RASs at amino acid positions 30, 62, 54, 58, and 98 are present within HCV genotypes 3a and 1. While keeping in mind that additional information was not available on the anonymous blood donors tested in this study, these findings can contribute to understand the NS5A mutation. Further study with known patients under drug treatment is recommended.

Mixed Infections Unravel Novel HCV Inter-Genotypic Recombinant Forms within the Conserved IRES Region

Hepatitis C virus (HCV) remains a significant global health challenge, affecting millions of people worldwide, with chronic infection a persistent threat. Despite the advent of direct-acting antivirals (DAAs), challenges in diagnosis and treatment remain, compounded by the lack of an effective vaccine. The HCV genome, characterized by high genetic variability, consists of eight distinct genotypes and over ninety subtypes, underscoring the complex dynamics of the virus within infected individuals. This study delves into the intriguing realm of HCV genetic diversity, specifically exploring the phenomenon of mixed infections and the subsequent detection of recombinant forms within the conserved internal ribosome entry site (IRES) region. Previous studies have identified recombination as a rare event in HCV. However, our findings challenge this notion by providing the first evidence of 1a/3a (and vice versa) inter-genotypic recombination within the conserved IRES region. Utilizing advanced sequencing methods, such as deep sequencing and molecular cloning, our study reveals mixed infections involving genotypes 1a and 3a. This comprehensive approach not only confirmed the presence of mixed infections, but also identified the existence of recombinant forms not previously seen in the IRES region. The recombinant sequences, although present as low-frequency variants, open new avenues for understanding HCV evolution and adaptation.

Molecular Analysis and Ex Vivo Infectivity of Seronegative Occult Hepatitis C Virus: A Study in Single Haemodialysis Centre

Background

In occult hepatitis C virus infection (OCI), hepatitis C virus ribonucleic acid (HCV RNA) is detectable in peripheral blood mononuclear cells (PBMCs) but is not evident in serum or plasma. Understanding of OCI in patients with seronegative anti-HCV antibodies is limited.

Methods

In this study, six HCV isolates from haemodialysis (HD) patients with seronegative OCI were identified by molecular assays and phylogenetic analysis. The virus infectivity was assessed ex vivo using a primary naïve PBMC culture system. HCV isolates obtained from the PBMCs of 10 patients with chronic HCV infection (CCI) were characterised concurrently and used as positive controls in the cell culture.

Results

Sequence analysis of the 5' untranslated region (UTR) and non-structural 5B (NS5B) region revealed that HCV genotype 3 was the most prevalent virus type in both the OCI and CCI groups. One of the occult HCV isolates was identified as a mixed type. The mean viral load (log10 RNA copies/106 cells) in the PBMC samples of the OCI group (M = 3.4, SD = 0.7) was lower than that of the CCI group (M = 4.6, SD = 1.7). Upon culture, de novo OCI-HCV replicates were detected in five out of six naïve PBMC cultures. Analysis of the replicates showed a single guanine addition in the domain III of 5'-UTR but the overall molecular structure was retained.

Conclusion

Seronegative OCI is an active form of infection that replicates at a low level in PBMCs. Seronegative OCI may share the same route of transmission as CCI. The retained viral competency may have an implication for its persistence.

Influence of Hepatitis C virus genotype and other factors on the viral load

Anti-HCV reactive subjects were selected and relevant data was collected. Viral load and genotype were determined for all patients and were divided into low (<800,000 IU/mL) and high viral load (>800,000 IU/mL). Correlation of viral load with parameters like age, gender, risk factors and genotype etc. was determined by binomial regression. Higher viral load was noted with genotype 4, males and high risk groups like People Who Inject Drugs (PWIDs), blood transfusion before routine testing or frequent transfusion, Intravenous drug therapy and MTP by unregistered medical practitioners (P ≤ 0.5). Prevention and treatment strategies for HCV should be tailored around these areas.

Long-term renal function alterations in hepatitis C patients with SVRs: Impacts of therapies and mixed cryoglobulinemia

BACKGROUND / AIMS

Effects of anti-hepatitis C virus (HCV) therapeutic regimens and mixed cryoglobulinemia on long-term renal function of HCV-infected patients with viral clearance have not been determined.

METHODS/MATERIALS

A prospective 10-year cohort study of 1212 HCV-infected patients (interferon-based therapy, n = 615; direct-acting antiviral (DAA) therapy, n = 434) was conducted.

RESULTS

At baseline, age, body mass index (BMI), hemoglobin (Hb) and uric acid (UA) levels, and fibrosis-4 score were associated with estimated glomerular filtration rates (eGFRs) in HCV-infected patients. At 24 weeks posttherapy, age, BMI, and Hb and UA levels were associated with eGFRs in patients with a sustained virological response (SVR) (n = 930). Compared with those at baseline, the eGFRs were lower in SVR patients at 24 weeks posttherapy, regardless of the therapeutic regimen. The eGFRs reverted to baseline levels in interferon-treated SVR patients up to 10 years posttherapy but remained decreased in DAA-treated SVR patients up to 4 years posttherapy. Longitudinally, repeated measures analyses with generalized estimating equations showed that the interactions between DAA-based therapy and mixed cryoglobulinemia (OR: 3.291) and Hb levels (1.778) were positively, while DAA-based therapy (0.442), age (0.956), UA levels (0.698), homeostasis model assessment-insulin resistance index (0.961) and complement 4 levels (0.9395) were negatively associated with the eGFR. Among DAA-treated SVR patients, the baseline eGFR (OR: 1.014; 95%CI OR: 1.004-1.023) and high-sensitivity C-reactive protein (HR: 1.082; 95%CI HR: 1.018-1.15) were associated with eGFR reduction at 24 weeks and 4 years posttherapy, respectively.

CONCLUSIONS

Hepatic fibrosis was an HCV-related factor for renal function. Longitudinally, DAA therapy was negatively, while the interaction between DAA therapy and mixed cryoglobulinemia was positively associated with renal function in SVR patients; deteriorated renal function was recovered in interferon-treated SVR patients. Particularly in DAA-treated SVR patients, baseline renal function and systemic inflammation were associated with short- and long-term reductions in renal function, respectively.

Hepatitis C: The Story of a Long Journey through First, Second, and Third Generation NS3/4A Peptidomimetic Inhibitors. What Did We Learn?

Hepatitis C viral (HCV) infection is the leading cause of liver failure and still represents a global health burden. Over the past decade, great advancements made HCV curable, and sustained viral remission significantly improved to more than 98%. Historical treatment with pegylated interferon alpha and ribavirin has been displaced by combinations of direct-acting antivirals. These regimens include drugs targeting different stages of the HCV life cycle. However, the emergence of viral resistance remains a big concern. The design of peptidomimetic inhibitors (PIs) able to fit and fill the conserved substrate envelope region within the active site helped avoid contact with the vulnerable sites of the most common resistance-associated substitutions Arg155, Ala156, and Asp168. Herein, we give an overview of HCV NS3 PIs discovered during the past decade, and we deeply discuss the rationale behind the structural optimization efforts essential to achieve pangenotypic activity.

Full-length sequence analysis of hepatitis C virus genotype 3b strains and development of an in vivo infectious 3b cDNA clone

IMPORTANCE

HCV genotype 3b is a difficult-to-treat subtype, associated with accelerated progression of liver disease and resistance to antivirals. Moreover, its prevalence has significantly increased among persons who inject drugs posing a serious risk of transmission in the general population. Thus, more genetic information and antiviral testing systems are required to develop novel therapeutic options for this genotype 3 subtype. We determined the complete genomic sequence and complexity of three genotype 3b isolates, which will be beneficial to study its biology and evolution. Furthermore, we developed a full-length in vivo infectious cDNA clone of genotype 3b and showed its robustness and genetic stability in human-liver chimeric mice. This is, to our knowledge the first reported infectious cDNA clone of HCV genotype 3b and will provide a valuable tool to evaluate antivirals and neutralizing antibodies in vivo, as well as in the development of infectious cell culture systems required for further research.

Computational identification of a multi-peptide vaccine candidate in E2 glycoprotein against diverse Hepatitis C virus genotypes

Hepatitis C Virus (HCV) is estimated to affect nearly 180 million people worldwide, culminating in ∼0.7 million yearly casualties. However, a safe vaccine against HCV is not yet available. This study endeavored to identify a multi-genotypic, multi-epitopic, safe, and globally competent HCV vaccine candidate. We employed a consensus epitope prediction strategy to identify multi-epitopic peptides in all known envelope glycoprotein (E2) sequences, belonging to diverse HCV genotypes. The obtained peptides were screened for toxicity, allergenicity, autoimmunity and antigenicity, resulting in two favorable peptides viz., P2 (VYCFTPSPVVVG) and P3 (YRLWHYPCTV). Evolutionary conservation analysis indicated that P2 and P3 are highly conserved, supporting their use as part of a designed multi-genotypic vaccine. Population coverage analysis revealed that P2 and P3 are likely to be presented by >89% Human Leukocyte Antigen (HLA) molecules from six geographical regions. Indeed, molecular docking predicted the physical binding of P2 and P3 to various representative HLAs. We designed a vaccine construct using these peptides and assessed its binding to toll-like receptor 4 (TLR-4) by molecular docking and simulation. Subsequent analysis by energy-based and machine learning tools predicted high binding affinity and pinpointed the key binding residues (i.e. hotspots) in P2 and P3. Also, a favorable immunogenic profile of the construct was predicted by immune simulations. We encourage the scientific community to validate our vaccine construct in vitro and in vivo.Communicated by Ramaswamy H. Sarma.

Optimizing HCV Disease Prediction in Egypt: The hyOPTGB Framework

The paper focuses on the hepatitis C virus (HCV) infection in Egypt, which has one of the highest rates of HCV in the world. The high prevalence is linked to several factors, including the use of injection drugs, poor sterilization practices in medical facilities, and low public awareness. This paper introduces a hyOPTGB model, which employs an optimized gradient boosting (GB) classifier to predict HCV disease in Egypt. The model's accuracy is enhanced by optimizing hyperparameters with the OPTUNA framework. Min-Max normalization is used as a preprocessing step for scaling the dataset values and using the forward selection (FS) wrapped method to identify essential features. The dataset used in the study contains 1385 instances and 29 features and is available at the UCI machine learning repository. The authors compare the performance of five machine learning models, including decision tree (DT), support vector machine (SVM), dummy classifier (DC), ridge classifier (RC), and bagging classifier (BC), with the hyOPTGB model. The system's efficacy is assessed using various metrics, including accuracy, recall, precision, and F1-score. The hyOPTGB model outperformed the other machine learning models, achieving a 95.3% accuracy rate. The authors also compared the hyOPTGB model against other models proposed by authors who used the same dataset.

A novel candidate hepatitis C virus genotype 4 subtype identified by next generation sequencing full-genome characterization in a patient from Saudi Arabia

Background and aim

Hepatitis C virus (HCV) infection is a major global public health concern, being a leading cause of chronic liver diseases such as chronic hepatitis, cirrhosis, and hepatocellular carcinoma. The virus is classified into 8 genotypes and 93 subtypes, each displaying distinct geographic distributions. Genotype 4 is the most predominant in the Middle East and Eastern Mediterranean and is associated with high rates of hepatitis C infection worldwide. This study used next-generation sequencing to fully characterize the HCV genome and identify a novel subtype within genotype 4 isolated from a 64-year-old Saudi man diagnosed with hepatitis C.

Methods

We analyzed the complete genome of the 141-HCV isolate using whole-genome sequencing.

Results

Our phylogenetic reconstructions, based on the entire genome of HCV-4 strains, revealed that the 141-HCV isolate formed a distinct group within the genotype 4 classification, providing valuable new insights into the variability of HCV.

Conclusion

This discovery of a previously unclassified HCV subtype within genotype 4 sheds light on the ongoing evolution and diversity of the virus. Such knowledge has significant implications for diagnostic and therapeutic approaches, as different subtypes may exhibit varying drug sensitivities and resistance profiles.

Computational medicinal chemistry applications to target Asian-prevalent strain of hepatitis C virus

Hepatitis C Virus (HCV), affecting millions of people worldwide, is the leading cause of liver disorder, cirrhosis, and hepatocellular carcinoma. HCV is genetically diverse having eight genotypes and several subtypes predominant in different regions of the globe. The HCV NS3/4A protease is a primary therapeutic target for HCV with various FDA-approved antivirals and several clinical developments. However, available protease inhibitors (PIs) have lower potency against HCV genotype 3 (GT3), prevalent in South Asia. In this study, the incumbent computational tools were utilized to understand and explore interactions of the HCV GT3 receptor with the potential inhibitors after the virtual screening of one million compounds retrieved from the ZINC database. The molecular dynamics, pharmacological studies, and experimental studies uncovered the potential PIs as ZINC000224449889, ZINC000224374291, and ZINC000224374456 and the derivative of ZINC000224374456 from the ZINC library. The study revealed that these top-hit compounds exhibited good binding and better pharmacokinetics properties that might be considered the most promising compound against HCV GT3 protease. Viability test, on primary healthy Human Gingival Fibroblasts (HGFs) and cancerous AGS cell line, was also carried out to assess their safety profile after administration. In addition, Surface Plasmon Resonance (SPR) was also performed for the determination of affinity and kinetics of synthesized compounds with target proteins.

Hepatitis C

Hepatitis C virus (HCV) is a hepatotropic RNA virus that can cause acute and chronic hepatitis, with progressive liver damage resulting in cirrhosis, decompensated liver disease, and hepatocellular carcinoma. In 2016, WHO called for the elimination of HCV infection as a public health threat by 2030. Despite some progress, an estimated 57 million people were living with HCV infection in 2020, and 300 000 HCV-related deaths occur per year. The development of direct-acting antiviral therapy has revolutionised clinical care and generated impetus for elimination, but simplified and broadened HCV screening, enhanced linkage to care, and higher coverage of treatment and primary prevention strategies are urgently required.

Prospects for developing an Hepatitis C virus E1E2-based nanoparticle vaccine

Globally, more than 58 million people are chronically infected with Hepatitis C virus (HCV) with 1.5 million new infections occurring each year. An effective vaccine for HCV is therefore a major unmet medical and public health need. Since HCV rapidly accumulates mutations, vaccines must elicit the production of broadly neutralising antibodies (bnAbs) in a reproducible fashion. Decades of research have generated a number of HCV vaccine candidates. Based on the available data and research through clinical development, a vaccine antigen based on the E1E2 glycoprotein complex appears to be the best choice, but robust induction of humoral and cellular responses leading to virus neutralisation has not yet been achieved. One issue that has arisen in developing an HCV vaccine (and many other vaccines as well) is the platform used for antigen delivery. The majority of viral vaccine trials have employed subunit vaccines. However, subunit vaccines often have limited immunogenicity, as seen for HCV, and thus multiple formats must be examined in order to elicit a robust anti-HCV immune response. Nanoparticle vaccines are gaining prominence in the field due to their ability to facilitate a controlled multivalent presentation and trafficking to lymph nodes, where they can interact with both arms of the immune system. This review discusses the potential for development of a nanoparticle-based HCV E1E2 vaccine, with an emphasis on the potential benefits of such an approach along with the major challenges facing the incorporation of E1E2 into nanoparticulate delivery systems and how those challenges can be addressed.

Clinical performance of the MAGLUMI Anti-HCV (CLIA) Test for detection of hepatitis C virus antibodies

BACKGROUND

Hepatitis C virus (HCV) infection screening and diagnosis are critical to control the hepatitis C epidemic. Testing for anti-HCV antibodies (Ab) in blood samples is the first step to screen people who have been infected with the virus.

OBJECTIVES

To evaluate the performance of the MAGLUMI Anti-HCV (CLIA) Test for detection of HCV antibodies.

STUDY DESIGN

To assess the diagnostic specificity, serum samples from 5053 unselected donors and 205 blood specimens from hospitalized patients were collected. To evaluate the diagnostic sensitivity, 400 positive HCV Ab samples were collected and 30 seroconversion panels were tested. All samples that met the test criteria were tested with the MAGLUMI Anti-HCV (CLIA) Test according to manufacturer's instruction. Results of the MAGLUMI Anti-HCV (CLIA) Test were compared with the Abbott ARCHITECT anti-HCV reference test.

RESULTS

The specificity of the MAGLUMI Anti-HCV (CLIA) Test was 99.75% and 100.00% in blood donor and hospitalized patient samples, respectively. The sensitivity of the Test in HCV Ab positive samples was 100.00%. Seroconversion sensitivity was comparable between the MAGLUMI Anti-HCV (CLIA) Test and the reference assay.

CONCLUSIONS

The performance of the MAGLUMI Anti-HCV (CLIA) Test makes it suited for HCV infection diagnosis.

Discovery of a fused bicyclic derivative of 4-hydroxypyrrolidine and imidazolidinone as a new anti-HCV agent

Hepatitis C virus (HCV) infection causes severe liver diseases and remains a major global public health concern. Current direct-acting antiviral (DAA)-based therapies that target viral proteins involving HCV genome replication are effective, however a minority of patients still fail to cure HCV, rendering a window to develop additional antivirals particularly targeting host functions involving in HCV infection. Here, we utilized the HCV infection cell culture system (HCVcc) to screen in-house compounds bearing host-interacting preferred scaffold for the antiviral activity. Compound HXL-10, a novel fused bicyclic derivative of pyrrolidine and imidazolidinone, was identified as a potent anti-HCV agent with a low cytotoxicity and high specificity. Mechanistic studies showed that HXL-10 neither displayed a virucidal effect nor inhibited HCV genomic RNA replication. Instead, HXL-10 might inhibit HCV assembly by targeting host functions. In summary, we developed a novel anti-HCV agent that may potentially offer additive benefits to the current anti-HCV DDA.

Metabolic, renal, and hematological changes in chronic hepatitis C patients achieving rapid virologic response after 12 weeks of direct-acting antiviral treatment: A prospective cohort study

The impact of direct-acting antivirals (DAA) therapy on lipid and glucose metabolism and kidney function in patients with hepatitis C virus (HCV) infection, along with its side effects on blood cells, remains controversial. Therefore, we conducted a study that enrolled 280 patients with HCV infection who achieved sustained virologic response after treatment with DAA therapy without ribavirin to evaluate the metabolic changes, renal function, and anemia risk based on real-world data. This study was an observational prospective study with a follow-up period of 12 weeks after the initiation of DAA therapy. Data on biochemical tests, renal function, blood counts, viral load, and host genomics were recorded before treatment and after 12 weeks of treatment with DAAs. DAA therapy reduced fibrosis-4 scores and improved liver function, with significant reductions in aspartate transaminase, alanine aminotransferase, and total bilirubin levels. However, DAA therapy slightly increased uric acid, cholesterol, and low-density lipoprotein cholesterol levels. It significantly reduced fasting blood glucose levels and hemoglobin A1C index (HbA1C) in the study group, while hemoglobin (Hb) and hematocrit (HCT) concentrations decreased significantly (4.78 ± 21.79 g/L and 0.09% ± 0.11%, respectively). The estimated glomerular filtration rate (eGFR) decreased by 12.89 ± 39.04 mL/min/1.73m2. Most variations were not related to the genotype, except for Hb, HCT, and HbA1C. Anemia incidence increased from 23.58% before treatment to 30.72% after treatment. Patients with HCV-1 genotype had a higher rate of anemia than did patients with genotype 6 (36.23% vs. 24.62%). Multivariate analysis showed that the risk of anemia was related to female sex, cirrhosis status, fibrosis-4 score, pretreatment eGFR, and pretreatment Hb level. The results of our study can provide helpful information to clinicians for the prognosis and treatment of HCV infection.

Therapeutic strategies and promising vaccine for hepatitis C virus infection

Hepatitis C virus (HCV) infection is still a significant global health problem despite therapeutic advancements. Ribavirin and interferon therapy have been the sole available treatments for HCV infection for a number of years with low efficacy. Thus, currently, a number of therapeutic strategies are being used, including nanoparticles (NPs), micro-RNAs such as small interfering RNA (siRNA), RNAi-based gene silencing and antisense oligonucleotide-based microRNA-122, microRNA-155, and short hairpin RNAs (shRNAs), and immunotherapeutic approaches such as anti-programmed cell death 1(PD-1), monoclonal antibodies (mAb or moAb), and monocyte-derived dendritic cells (Mo-DCs). Furthermore, direct-acting antivirals (DAAs) and host-targeting agents (HTA) were also the current therapeutic approaches with great efficacy. In spite of different clinical trials on HCV vaccine developments, nowadays there is no effective HCV vaccine in opposition to virus due to various challenges including genetic diversity, lack of immunocompetent small animal models, shortage of HCV vaccination testing alternatives, lack of an effective tissue culture method for replicating HCV, and inadequate knowledge regarding to immune responses against HCV infection. Nowadays, mRNA vaccine, recombinant viral vector, peptides vaccine, virus-like particles, DNA vaccine, rational designed vaccine, and recombinant polyantigenic T-cell-based vaccine are novel promising candidates for HCV vaccine based on various clinical trials. This review summarizes the different therapeutic approaches and the advancements of vaccine candidates for HCV infection.

Microorganisms-derived antigens for preventive anti-cancer vaccines

Cancer prevention is one of the aim with the highest priority in order to reduce the burden of cancer diagnosis and treatment on individuals as well as on healthcare systems. To this aim, vaccines represent the most efficient primary cancer prevention strategy. Indeed, anti-cancer immunological memory elicited by preventive vaccines might promptly expand and prevent tumor from progressing. Antigens derived from microorganisms (MoAs), represent the obvious target for developing highly effective preventive vaccines for virus-induced cancers. In this respect, the drastic reduction in cancer incidence following HBV and HPV preventive vaccines are the paradigmatic example of such evidence. More recently, experimental evidences suggest that MoAs may represent a "natural" anti-cancer preventive vaccination or can be exploited for developing vaccines to prevent cancers presenting highly homologous tumor-associated antigens (TAAs) (e.g. molecular mimicry). The present review describes the different preventive anti-cancer vaccines based on antigens derived from pathogens at the different stages of development.

Study of drug resistance-associated genetic mutations, and phylo-genetic analysis of HCV in the Province of Sindh, Pakistan

Current management of HCV infection is based on Direct-Acting Antiviral Drugs (DAAs). However, resistance-associated mutations, especially in the NS3 and NS5B regions are gradually decreasing the efficacy of DAAs. The aim of the current study was to identify such mutations in the NS3, and NS5B genes in DAAs treatment-naïve Pakistani chronic HCV 3a patients. Peripheral blood samples were collected from 233 chronic HCV 3a patients at different tertiary care hospitals in Karachi, Pakistan, between August 2020 to September 2021. PCR-amplified target regions of the NS3/NS5B gene were subjected to Sanger sequencing to identify resistance-associated mutations. Phylogenetic analysis of the identified amino acid sequences was performed using HCV3a sequences of the global population in the virus pathogen resource (VIPR) database. Sequence analysis identified five amino acid mutations, Leu36Pro, Gln41His, Gln80Lys/Arg, Ala156Tyr, and Gln168Arg in the NS3 region, and two mutations Leu159Phe and Cys316Arg in the NS5B region. Phylogenetic analysis revealed a high genetic diversity in the studied isolates. Overall, the prevalence of resistance-associated substitutions was almost similar to other geographic regions worldwide. This data could be helpful in selecting the most effective treatment regimen for HCV chronically infected people in Pakistan.

The distribution of hepatitis C viral genotypes shifted among chronic hepatitis C patients in Yunnan, China, between 2008-2018

Object

The hepatitis C virus (HCV) is prevalent across China, with a distinctive genotypic distribution that varies by geographical region and mode of transmission. Yunnan is one such geographical region wherein the local population continues to experience a high level of HCV infection, severely straining public health resources. This high prevalence is likely due to the increased incidence of intravenous drug use in that region, as Yunnan is a major point of entry for illegal heroin into China.

Methods

We investigated 510 individuals with chronic HCV infections in Yunnan Province from 2008 through 2018. Using reverse transcription PCR and Sanger sequencing to amplify and sequence samples. Bayesian analyses was performed to estimate the common ancestors and Bayesian skyline plot to estimate the effective viral population size. Molecular network was conducted to explore the characteristics of HCV transmission.

Results

We successfully amplified and sequenced a total of 503 viral samples and genotyped each as either 3b (37.6%), 3a (21.9%), 1b (19.3%), 2a (10.5%), HCV-6 (10.1%), or 1a (0.6%). Over this 11-year period, we observed that the proportion of 3a and 3b subtypes markedly increased and, concomitantly, that the proportion of 1b and 2a subtypes decreased. We also performed Bayesian analyses to estimate the common ancestors of the four major subtypes, 1b, 2a, 3a, and 3b. Finally, we determined that our Bayesian skyline plot and transmission network data correlated well with the changes we observed in the proportions of HCV subtypes over time.

Conclusions

Taken together, our results indicate that the prevalence of HCV 3a and 3b subtypes is rapidly increasing in Yunnan, thus demonstrating a steadily growing public health requirement to implement more stringent preventative and therapeutic measures to curb the spread of the virus.

Clinical Practice Guidelines of the Russian Society for the Study of the Liver, the Russian Gastroenterological Association, the National Scientific Society of Infectious Disease Specialists for the Diagnosis and Treatment of Chronic Hepatitis C

Аim:diagnosis and treatment algorithms in the clinical recommendations intended for general practitioners, gastroenterologists, infectious disease specialists, hepatologists on the of chronic hepatitis C are presented.

Summary.Chronic viral hepatitis C is a socially significant infection, the incidence of which in the Russian Federation remains significantly high. Over the past 10 years, great progress has been made in the treatment of hepatitis C — direct acting antiviral drugs have appeared. The spectrum of their effectiveness allows to achieve a sustained virological response in more than 90 % of cases, even in groups that were not previously considered even as candidates for therapy or were difficult to treat — patients receiving renal replacement therapy, after liver transplantation (or other organs), at the stage of decompensated liver cirrhosis, HIV co-infected, etc. Interferons are excluded from the recommendations due to their low effectiveness and a wide range of adverse events. The indications for the treatment have been expanded, namely, the fact of confirmation of viral replication. The terms of dispensary observation of patients without cirrhosis of the liver have been reduced (up to 12 weeks after the end of therapy). Also, these recommendations present approaches to active screening of hepatitis in risk groups, preventive and rehabilitation measures after the end of treatment.

Conclusion.Great success has been achieved in the treatment of chronic hepatitis C. In most cases, eradication of viral HCV infection is a real task even in patients at the stage of cirrhosis of the liver, with impaired renal function, HIV co-infection, after solid organs transplantation.

Current Hepatitis C Vaccine Candidates Based on the Induction of Neutralizing Antibodies

The introduction of direct-acting antivirals (DAAs) has revolutionized hepatitis C treatment. Short courses of treatment with these drugs are highly beneficial to patients, eliminating hepatitis C virus (HCV) without adverse effects. However, this outstanding success is tempered by the continuing difficulty of eradicating the virus worldwide. Thus, access to an effective vaccine against HCV is strongly needed to reduce the burden of the disease and contribute to the elimination of viral hepatitis. The recent failure of a T-cell vaccine based on the use of viral vectors expressing the HCV non-structural protein sequences to prevent chronic hepatitis C in drug users has pointed out that the induction of neutralizing antibodies (NAbs) will be essential in future vaccine candidates. To induce NAbs, vaccines must contain the main target of this type of antibody, the HCV envelope glycoproteins (E1 and E2). In this review, we summarize the structural regions in E1 and E2 proteins that are targeted by NAbs and how these proteins are presented in the vaccine candidates currently under development.

Sub-genotypes of hepatitis C virus in the Middle East and North Africa: Patterns of distribution and temporal changes

Infection with the hepatitis C virus (HCV) remains a considerable public health concern in the Middle East and North Africa (MENA). The objectives of this study were to analyze the HCV genotype (GT) and sub-genotype (SGT) distribution in the MENA region and to assess the temporal change in the number of sequences within the MENA region. All HCV molecular sequences collected in the MENA region had been retrieved from GenBank as of 1 August 2022. The number of HCV sequences retrieved was 6740 representing sequences from a total of 17 MENA countries with a majority from Iran (n = 1969, 29.2%), Egypt (n = 1591, 23.6%), Tunisia (n = 1305, 19.4%) and Saudi Arabia (n = 1085, 16.1%). The determination of GT/SGT was based on the NCBI genotyping and Blast tool. Genotype 1 (GT1) dominated infections in the MENA (n = 2777, 41.2%), followed by GT4 (n = 2566, 39.0%). Additionally, SGT4a (1515/6393, 23.7%) was the most common SGT in the MENA, and SGT4a was dominant in Egypt and Saudi Arabia, followed by SGT1b (n = 1308, 20.5%), which was dominant in Morocco and Tunisia, while SGT1a (n = 1275, 19.9%) was common in Iran, Iraq and Palestine. Furthermore, significant temporal increase in the number of HCV MENA sequences was observed. On the SGT level, specific patterns of HCV genetic diversity were seen in the MENA region, with the most common SGT being 4a, in addition to increasing the availability of HCV sequences in the MENA region.

Potential roles of core and core+1 proteins during the chronic phase of hepatitis C virus infection

The HCV Core protein is a multifunctional protein that interacts with many viral and cellular proteins. In addition to the encapsidation of the viral genome, it can disturb various cellular pathways and impede antiviral cellular responses such as interferon (IFN) production. The Core protein can also disrupt the functions of immune cells against HCV. The Core protein helps viral infection persistency by interfering with apoptosis. The Core+1 protein plays a significant role in inducing chronic HCV infection through diverse mechanisms. We review some of the mechanisms by which Core and Core+1 proteins facilitate HCV infection to chronic infection. These proteins could be considered for designing more sufficient treatments and effective vaccines against HCV.

Identification of novel neutralizing determinants for protection against HCV

BACKGROUND AND AIMS

HCV evasion of neutralizing antibodies (nAb) results in viral persistence and poses challenges to the development of an urgently needed vaccine. N-linked glycosylation of viral envelope proteins is a key mechanism for such evasion. To facilitate rational vaccine design, we aimed to identify determinants of protection of conserved neutralizing epitopes.

APPROACH AND RESULTS

Using a reverse evolutionary approach, we passaged genotype 1a, 1b, 2a, 3a, and 4a HCV with envelope proteins (E1 and E2) derived from chronically infected patients without selective pressure by nAb in cell culture. Compared with the original viruses, HCV recombinants, engineered to harbor substitutions identified in polyclonal cell culture-passaged viruses, showed highly increased fitness and exposure of conserved neutralizing epitopes in antigenic regions 3 and 4, associated with protection from chronic infection. Further reverse genetic studies of acquired E1/E2 substitutions identified positions 418 and 532 in the N1 and N6 glycosylation motifs, localizing to adjacent E2 areas, as key regulators of changes of the E1/E2 conformational state, which governed viral sensitivity to nAb. These effects were independent of predicted glycan occupancy.

CONCLUSIONS

We show how N-linked glycosylation motifs can trigger dramatic changes in HCV sensitivity to nAb, independent of glycan occupancy. These findings aid in the understanding of HCV nAb evasion and rational vaccine design, as they can be exploited to stabilize the structurally flexible envelope proteins in an open conformation, exposing important neutralizing epitopes. Finally, this work resulted in a panel of highly fit cell culture infectious HCV recombinants.

Hepatitis C subtyping assay failure in UK patients born in sub-Saharan Africa: Implications for global treatment and elimination

BACKGROUND AND AIMS: The newly developed direct-acting antivirals have revolutionized the treatment of chronic hepatitis C virus (HCV), with cure rates as high as 98% in some cohorts. Although genome sequencing has demonstrated that some subtypes of HCV naturally harbor drug resistance associated substitutions (RAS), these are often overlooked as "rarities." Furthermore, commercial subtyping assays and associated epidemiological findings are skewed towards Western cohorts and whole-genome sequencing can be problematic to deploy without significant infrastructure and training support. We thus aimed to develop a simple, robust and accurate HCV subtyping pipeline, to optimize and streamline molecular detection and sequence-based typing of diverse RAS-containing subtypes.

METHODS

HCV serum derived from 146 individuals, whose likely source of infection was from sub-Saharan Africa (SSA) was investigated with a novel panel of single round polymerase chain reaction (PCR) assays targeting NS5B and NS5A genomic regions. Virus subtype assignments were determined by pairwise-distance analysis and compared to both diagnostic laboratory assignments and free-to-use online typing tools.

RESULTS

Partial NS5A and NS5B sequences were respectively obtained from 131 to 135 HCV-positive patients born in 19 different countries from SSA but attending clinics in the UK. We determined that routine clinical diagnostic methods incorrectly subtyped 59.0% of samples, with a further 6.8% incorrectly genotyped. Of five commonly used online tools, Geno2Pheno performed most effectively in determining a subtype in agreement with pairwise distance analysis.

CONCLUSION

This study provides a simple low-cost pathway to accurately subtype in SSA, guide regional therapeutic choice and assist global surveillance and elimination initiatives.

Mechanisms and Consequences of Genetic Variation in Hepatitis C Virus (HCV)

Chronic infection with hepatitis C virus (HCV) is an important contributor to the global incidence of liver diseases, including liver cirrhosis and hepatocellular carcinoma. Although common for single-stranded RNA viruses, HCV displays a remarkable high level of genetic diversity, produced primarily by the error-prone viral polymerase and host immune pressure. The high genetic heterogeneity of HCV has led to the evolution of several distinct genotypes and subtypes, with important consequences for pathogenesis, and clinical outcomes. Genetic variability constitutes an evasion mechanism against immune suppression, allowing the virus to evolve epitope escape mutants that avoid immune recognition. Thus, heterogeneity and variability of the HCV genome represent a great hindrance for the development of vaccines against HCV. In addition, the high genetic plasticity of HCV allows the virus to rapidly develop antiviral resistance mutations, leading to treatment failure and potentially representing a major hindrance for the cure of chronic HCV patients. In this chapter, we will present the central role that genetic diversity has in the viral life cycle and epidemiology of HCV. Incorporation errors and recombination, both the result of HCV polymerase activity, represent the main mechanisms of HCV evolution. The molecular details of both mechanisms have been only partially clarified and will be presented in the following sections. Finally, we will discuss the major consequences of HCV genetic diversity, namely its capacity to rapidly evolve antiviral and immunological escape variants that represent an important limitation for clearance of acute HCV, for treatment of chronic hepatitis C and for broadly protective vaccines.

Epidemiology and Genotype Distribution of Hepatitis C Virus in Russia

The hepatitis C virus (HCV) causes both acute and chronic infection of the liver that can lead to liver cirrhosis, cancer, and liver failure. HCV is characterized by high genetic diversity and substantial variations in the prevalence of specific HCV genotypes throughout the world. Many effective regimens of direct-acting antivirals (DAAs), including pan-genotypic, can successfully treat HCV infection. Additionally, genotype-specific treatments for HCV are being actively employed in national plans for eliminating HCV infection around the world. The evaluation of HCV genotype prevalence in a given country is necessary for the successful implementation of the HCV elimination plans and for allocating financial resources to the DAAs which are the most effective against those specific HCV genotypes prevalent in a given country. Here, we analyzed HCV genotypes, subgenotypes, and recombinants in 10,107 serum samples collected in 2015-2017 from patients with chronic HCV infection living in all federal districts of Russia. This is the first and largest evaluation of HCV genotypes performed on samples from all territories of Russia, from its Central federal district to the Far East. Moreover, we have updated retrospective epidemiological analysis of chronic and acute HCV infection in Russia from 2001 to 2021. We demonstrate that the incidence of acute HCV (AHC) infection in Russia decreased from 16.7 cases per 100,000 people in 2001 to 0.6/100,000 in 2021. The number of cases of chronic HCV (CHC) infection also decreased from 29.5 to 16.4 per 100,000 people during this period. The HCV genotype analysis indicated that HCV genotype 1 dominates in Russia (53.6%), while genotypes 3 and 2 were detected in 35.4% and 7.8% of patients, respectively. These proportions are virtually identical in all regions of Russia except for the Far East, where HCV genotype 2 was detected in only 1% of the samples. HCV genotypes 1 and 2 are more widespread in women, and HCV genotype 3 in men. Genotype 3 was the most prevalent in 31-40-year-olds (44.9%), and genotype 1 was most prevalent in those over 70 years of age (72.2%). HCV genotype 2 was predominant among HCV-infected persons older than 40 years. Discriminating between HCV genotype 2 and recombinant RF1_2k/1b, which are frequently misclassified, is important for successful antiviral treatment. For the first time, we demonstrate, here, countrywide prevalence of HCV RF1_2k/1b in different regions of Russia. HCV RF1_2k/1b makes up 3.2% of HCV genotypes, reaching 30% among samples classified as genotype 2 by some commercial genotyping tests. The highest proportion of HCV RF1_2k/1b was detected in the North-West (60%), Southern (41.6%), and Central (31.6%) federal districts; its frequency in the Far Eastern and North Caucasus districts was ~14.3%. HCV RF1_2k/1b, and it was not detected in the Volga, Ural, or Siberian districts. To conclude, this is the first and most complete evaluation of HCV epidemiology and genotype/subgenotype distribution in Russia.