Prevalence of chronic HCV infection in EU/EEA countries in 2019 using multiparameter evidence synthesis.

Background: Epidemiological data are crucial to monitoring progress towards the 2030 Hepatitis C Virus (HCV) elimination targets. Our aim was to estimate the prevalence of chronic HCV infection (cHCV) in the European Union (EU)/European Economic Area (EEA) countries in 2019. Methods: Multi-parameter evidence synthesis (MPES) was used to produce national estimates of cHCV defined as: π = πrecρrec + πexρex + πnonρnon; πrec, πex, and πnon represent cHCV prevalence among recent people who inject drugs (PWID), ex-PWID, and non-PWID, respectively, while ρrec, ρex, and ρnon represent the proportions of these groups in the population. Information sources included the European Centre for Disease Prevention and Control (ECDC) national operational contact points (NCPs) and prevalence database, the European Monitoring Centre for Drugs and Drug Addiction databases, and the published literature. Findings: The cHCV prevalence in 29 of 30 EU/EEA countries in 2019 was 0.50% [95% Credible Interval (CrI): 0.46%, 0.55%]. The highest cHCV prevalence was observed in the eastern EU/EEA (0.88%; 95% CrI: 0.81%, 0.94%). At least 35.76% (95% CrI: 33.07%, 38.60%) of the overall cHCV prevalence in EU/EEA countries was associated with injecting drugs. Interpretation: Using MPES and collaborating with ECDC NCPs, we estimated the prevalence of cHCV in the EU/EEA to be low. Some areas experience higher cHCV prevalence while a third of prevalent cHCV infections was attributed to PWID. Further efforts are needed to scale up prevention measures and the diagnosis and treatment of infected individuals, especially in the east of the EU/EEA and among PWID. Funding: ECDC.

Combining cross-sectional survey and register data improved the estimate of hepatitis C prevalence among patients attending a psychiatric emergency department in Denmark.

BACKGROUND: The prevalence of hepatitis C (HCV) among psychiatric patients is elevated compared to the background population in many studies, but the prevalence among Danish psychiatric patients is unknown. The aim of the study was to determine the HCV prevalence and the proportion of the psychiatric patient population that remains to be diagnosed and treated in a Danish setting. METHODS: During a 5-month period, patients attending the psychiatric emergency room in Vejle, Denmark, were offered point-of-care anti-HCV testing. Previous hepatitis C tests for all patients attending the Psychiatric Department in the study period were extracted from the national laboratory database (DANVIR). We combined the survey and register data in a capture-recapture estimate of undiagnosed patients with HCV. RESULTS: During the study 24.9% (589 of 2364) patients seen at the psychiatric department attended the emergency room. The prevalence of anti-HCV among those tested in the emergency room was 1.6%. The laboratory register identified 595/2364 patients previously tested for anti-HCV with a positive prevalence of 6.1%. The undiagnosed anti-HCV positives among the 1483 never tested was estimated to 1.1%. Thus the total estimated prevalence of anti-HCV was 2.3% (54/2364, 95% CI 1.7%-3.0%) in the population, of whom 70.4% had been diagnosed, and 72.2% of diagnosed patients had received treatment or cleared HCV. CONCLUSION: Combining survey and register data showed that the WHO target of 90% diagnosed and 80% treated was not met. To eliminate HCV in the psychiatric population, both undiagnosed and untreated patients must be targeted.

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.

Hepatitis C screening and linkage to care with a mobile clinic in Southern Denmark.

BACKGROUND: Knowing the prevalence of hepatitis C (HCV) in risk groups is essential for elimination. The aim of the study was to assess HCV prevalence among people with different risk profiles and the feasibility of linking people with HCV to care. METHODS: In Southern Denmark we tested people who were using shelters, cafés, and facilities for marginalized populations and the general population. We established a mobile clinic for HCV testing offering point-of-care HCV-antibody (HCV-Ab), point-of-care HCV RNA testing, and dried blood spot (DBS) testing. People with HCV infection were linked to care. RESULTS: Among 802 tested persons, we found an HCV-Ab /HCV RNA prevalence of 13% (n = 101) /3% (n = 24). We found a prevalence of 20% (n = 97)/5% (n = 24) among 475 persons tested at locations attended by people who inject drugs but 0%/0% when testing the general population. Of 24 people who were HCV RNA positive, 83% (n = 20) initiated treatment, 13% (n = 3) spontaneously cleared their infection, and one was lost to follow-up. CONCLUSION: General population testing has limited utility while focus on settings attended by people with increased HCV risk is more feasible. Linkage of people with a current HCV infection to care is feasible.

Retrieval of patients with hepatitis C who were lost to follow-up in Southern Denmark.

BACKGROUND: The goal of the C-Free-South project is to eliminate hepatitis C (HCV) in the Region of Southern Denmark (1.2 million inhabitants). One target group consists of people with HCV who had received care but were lost to follow-up. The study aim was to evaluate program efficacy in locating these patients and getting them into care. METHODS: Patients were contacted if they were HCV-RNA positive and age 18+ years, registered in the clinical hepatitis database as of November 1, 2019, and had no scheduled HCV-related appointment. They were contacted at 2-month intervals by phone or letter. For patients who did not respond, we asked their general practitioner to refer them, if possible. RESULTS: We identified 69 (7%) patients in the database who were listed as untreated and not being followed up. We successfully contacted 54 (78%), and the remaining 15 (22%) did not respond to our contacts. To date, 45 (65%) had initiated treatment, one (1%) had rejected treatment, and eight (12%) did not show up to their appointments. Among those receiving treatment, 20 (44%) responded after the first contact, 18 (40%) after the second contact, and 7 (16%) after informing the general practitioner. CONCLUSION: An intensified and persistent effort made it possible to reach most HCV patients lost to follow-up. All new contact attempts increased the possibility that patients would receive treatment. Nevertheless, 22% of HCV patients lost to follow-up did not respond to repeated contact attempts.

Increasing prevalence of chronic hepatitis B virus infection and low linkage to care in Denmark on 31 December 2016 - an update based on nationwide registers.

OBJECTIVES: We aimed to update the estimated prevalence of both diagnosed and undiagnosed chronic hepatitis B virus infection in Denmark. Moreover, we aimed to determine the number of people with chronic hepatitis B virus infection in specialised care and to assess the completeness of reporting to the national register of communicable diseases. METHODS: Using four registers with national coverage, we identified all individuals registered with chronic hepatitis B virus infection, aged 16 years or older, and alive in Denmark on 31 December 2016. The diagnosed population was then estimated using capture-recapture analysis. The undiagnosed population was estimated using data from the Danish pregnancy screening program. RESULTS: We estimated that 14,548 individuals were living with chronic hepatitis B virus infection corresponding to 0.3% of the Danish population. Of them, 13,530 (93%) were diagnosed and 7942 (55%) were registered in one or more of the source registers. Only 4297 (32%) diagnosed individuals had attended specialised care and only 3289 cases (24%) were reported to the Danish communicable disease register. CONCLUSION: The prevalence of chronic hepatitis B virus infection increased from 2007 to 2017. The majority that had been diagnosed did not receive care as recommended by national guidelines and were not reported to the communicable diseases register responsible for hepatitis B virus surveillance. Future efforts should focus on linking individuals diagnosed with chronic hepatitis B virus infection to specialised care and improving reporting to the hepatitis B virus surveillance system.

Incidence of Hepatocellular Carcinoma and Decompensated Liver Cirrhosis and Prognostic Accuracy of the PAGE-B HCC Risk Score in a Low Endemic Hepatitis B Virus Infected Population.

Purpose: We aimed to determine incidence of hepatocellular carcinoma (HCC) and decompensated liver cirrhosis in persons with chronic hepatitis B virus (HBV) infection in Denmark stratified by disease phase, liver cirrhosis, and treatment status at baseline. Additionally, we aimed to assess the prognostic value of the PAGE-B HCC risk score in a mainly non-cirrhotic population. Patients and Methods: In this register-based cohort study, we included all individuals over the age of 18, with chronic HBV infection first registered between 2002 and 2016 in at least one of three nationwide registers. The study population was followed until HCC, decompensated liver cirrhosis, death, emigration, or December 31, 2017, which ever came first. Results: Among 6016 individuals included in the study, 10 individuals with and 23 without baseline liver cirrhosis developed HCC during a median follow up of 7.3 years (range 0.0-15.5). This corresponded to five-year cumulative incidences of 7.1% (95% confidence interval (CI) 2.0-12.3) and 0.2% (95% CI 0.1-0.4) in persons with and without baseline liver cirrhosis. The five-year cumulative incidence of decompensated liver cirrhosis was 0.7% (95% CI 0.5-1.0). Among 2038 evaluated for liver events stratified by disease phase, incidence of HCC was low in all who were non-cirrhotic and untreated for HBV at baseline. PAGE-B score was evaluated in 1529 persons. The 5-year cumulative incidence of HCC was 0, 0.8 (95% CI 0.5-1.8), and 8.7 (95% CI 1.0-16.4) in persons scoring <10, 10-17 and >17, respectively (c-statistic 0.91 (95% CI 0.84-0.98)). Conclusion: We found low incidence of HCC and decompensated liver cirrhosis in persons with chronic HBV infection in Denmark. Moreover, the PAGE-B score showed good accuracy for five-year risk of developing HCC in the population with chronic HBV infection in Denmark.

Ischemic Heart Disease in Chronic Hepatitis B: A Danish Nationwide Cohort Study.

Objective: Data on the risk of ischemic heart disease (IHD) in patients with chronic hepatitis B virus (CHB) are conflicting. Our objective was to address the rate of IHD in patients with CHB compared with individuals without CHB (control-persons) from the general population. Study Design and Setting: We conducted a cohort study of prospectively obtained data from Danish nationwide registries. We produced cumulative incidence curves and calculated the unadjusted incidence rate ratio (IRR) of IHD in persons with and without CHB. The adjusted association between having CHB and developing IHD was examined using a cause-specific Cox regression model. Results: In total, 6472 persons with CHB and 62,251 age- and sex-matched individuals from the general population were followed for 48,840 and 567,456 person-years, respectively, during which 103 (1,59%) with CHB and 1058 (1,70%) control-persons developed IHD. The crude IRR was 1.13 (95% CI: 0.91-1.39). CHB did not have a statistically significant effect on the rate of IHD after adjusting for several confounding factors (adjusted hazard ratio: 0.96, 95% CI: 0.76-1.21). Conclusion: In this nationwide cohort study, we did not find any difference between rate of IHD in persons with CHB in comparison with the general population.

Immunological Characteristics of Patients Receiving Ultra-Short Treatment for Chronic Hepatitis C.

Reducing the treatment duration for chronic hepatitis C could be an important tool in the effort to reach the elimination goals set by the World Health Organization. The current challenge is to predict the target group who will achieve sustained virological response at week 12 (SVR12) with shorter treatment duration. The aim of this exploratory study was to characterize immune subsets with focus on inhibitory receptors in patients who experienced SVR12 or virological relapse following four weeks treatment with glecaprevir/pibrentasvir with or without ribavirin. A total of 32 patients were included in this study of whom 21 achieved SVR12 and 11 had virological relapse. All available samples at baseline (n = 31) and end of treatment (EOT) (n = 30) were processed for flow cytometric analysis in order to measure the expression of PD-1, 2B4, BY55, CTLA-4, TIM-3 and LAG-3 on 12 distinct T cell subsets. At baseline, patients with SVR12 (n=21) had numerically lower frequencies of inhibitory receptors for 83% (60/72) of the investigated T-cell subtypes. The most significant difference observed between the two groups was a lower frequency of stem cell-like memory T-cells CD4+PD1+ in the SVR group (p = 0.007). Furthermore, we observed a significant positive correlation between baseline viral load and the expression of PD-1 on the total CD8+ T-cells and effector memory T-cells CD4+ and CD8+ for patients with virological relapse. This study suggests a measurable immunologic phenotype at baseline of patients achieving SVR12 after short treatment compared to patients with virological relapse.

Mortality and cause of death in persons with chronic hepatitis B virus infection versus healthy persons from the general population in Denmark.

The study aimed to determine adjusted all-cause mortality and cause of death in persons with chronic hepatitis B virus (HBV) infection compared with age- and sex-matched persons from the general population. We used nationwide registers to identify persons aged ≥18 years with chronic HBV infection in 2002-2017 in Denmark and included 10 age- and sex-matched controls for each. Follow-up was from 6 months after diagnosis until death, emigration, or 31 December 2017. Mortality rate ratios (MRRs) adjusted for age, sex, employment, origin and comorbidity were calculated using Poisson regression. Unadjusted cause-specific mortality rate ratios with 95% confidence intervals were calculated assuming a Poisson distribution. A total of 6988 persons with chronic HBV infection and 69,847 controls were included. During a median follow-up of 7.7 years (range 0.0-15.5), 315 (5%) persons with-and 1525 (2%) without-chronic HBV infection died. The adjusted all-cause MRR was 1.5 (95% CI 1.2-2.0). Persons with chronic HBV infection had increased mortality due to liver disease including hepatocellular carcinoma (MRR 12.3 [8.6-17.7]), external causes (MRR 3.3 [2.5-4.7]), endocrine disease (MRR 3.2 [1.8-5.4]), genitourinary disease (MRR 3.2 [1.2-7.6]) and neoplasms (except hepatocellular carcinoma; MRR 1.6 [1.2-2.0]). In conclusion, this study showed an increased all-cause mortality in persons with chronic HBV infection in comparison with age- and sex-matched persons without chronic HBV infection which remained after adjustment for several confounding factors. Excess mortality was mainly associated with liver disease, but also external factors, endocrine disease, genitourinary disease and neoplasms (excluding hepatocellular carcinoma).

A multi-level intervention to eliminate hepatitis C from the Region of Southern Denmark: the C-Free-South project.

Denmark has signed the WHO strategy to eliminate hepatitis C virus (HCV). In the absence of a national strategy for elimination, a local action plan was developed in the Region of Southern Denmark (RSD). The aim of the strategy is to diagnose 90% of HCV-infected persons and treat 80% of those diagnosed by 2025. The strategy was developed by reviewing Danish data on HCV epidemiology and drug use to identify key populations for screening, linkage to care, and treatment. Based on available published data from 2016, an estimated 3028 persons in the RSD were HCV-RNA positive (population prevalence 0.21%). Of these, 1002 were attending clinical care, 1299 were diagnosed but not in clinical care, and 727 were undiagnosed. Three different interventions targeting the HCV-infected population and two interventions for HCV surveillance are planned to achieve elimination. The "C-Free-South" strategy aims to eliminate HCV in our region by identifying (90%) and treating (80%) of infected persons by the end of 2025, 5 years earlier than the WHO elimination target date.

Four Weeks Treatment with Glecaprevir/Pibrentasvir + Ribavirin-A Randomized Controlled Clinical Trial.

Enhancing treatment uptake for hepatitis C to achieve the elimination goals set by the World Health Organization could be achieved by reducing the treatment duration. The aim of this study was to compare the sustained virological response at week 12 (SVR12) after four weeks of glecaprevir/pibrentasvir (GLE/PIB) + ribavirin compared to eight weeks of GLE/PIB and to estimate predictors for SVR12 with four weeks of treatment through a multicenter open label randomized controlled trial. Patients were randomized 2:1 (4 weeks:8 weeks) and stratified by genotype 3 and were treatment naïve of all genotypes and without significant liver fibrosis. A total of 27 patients were analyzed for predictors for SVR12, including 15 from the first pilot phase of the study. In the 'modified intention to treat' group, 100% (7/7) achieved cure after eight weeks and for patients treated for four weeks the SVR12 was 58.3% (7/12). However, patients with a baseline viral load <2 mill IU/mL had 93% SVR12. The study closed prematurely due to the low number of included patients due to the COVID-19 pandemic. Our results suggest that viral load should be taken into account when considering trials of short course treatment.

Soluble inflammatory mediators identify HCV patients who may be cured with four weeks of antiviral treatment.

Soluble inflammatory mediators (SIM) can be predictive of treatment outcome in antiviral treatment of chronic hepatitis C. Recently, it was shown that a subgroup of patients can be cured with four weeks of therapy. We here profiled patients for 70 SIM before and during treatment of hepatitis C with glecaprevir/pibrentasvir (GLE/PIB) +/- ribavirin. Proximity extension assay was performed in a total of 32 patients. Pre-treatment SIM profiles did not distinguish patients achieving an SVR (n = 21) from patients experiencing antiviral relapse (n = 11). However, after 4 weeks of therapy, eight markers were identified that could distinguish patients with SVR from the relapsed group, namely MMP-10, CCL20, CXCL11, FGF-23, TNF, MCP-2, IL-18R1 and CXCL10. Thus, this study shows that a distinct on-treatment immune profile is associated with cure of HCV infection after ultrashort treatment.

Hepatitis C time trends in reported cases and estimates of the hidden population born before 1965, Denmark and Sweden, 1990 to 2020.

BackgroundAccording to the World Health Organization, hepatitis C virus (HCV) infection should be under control by 2030.AimOur aim was to describe the size and temporal changes in reported cases of chronic HCV infection in Denmark and Sweden and to estimate the size of the hidden (undiagnosed) population born before 1965.MethodsWe extracted all HCV infections reported to national surveillance systems in Denmark and Sweden from 1990 to 2020. Prediction of the size of the hidden HCV-infected population was restricted to the cohort born before 1965 and cases reported up to 2017. We applied a model based on removal sampling from binomial distributions, estimated the yearly probability of diagnosis, and deducted the original HCV-infected population size.ResultsDenmark (clinician-based) reported 10 times fewer hepatitis C cases annually than Sweden (laboratory and clinician-based), peaking in 2007 (n = 425) and 1992 (n = 4,537), respectively. In Denmark, the birth year distribution was monophasic with little change over time. In recent years, Sweden has had a bimodal birth year distribution, suggesting ongoing infection in the young population. In 2017, the total HCV-infected population born before 1965 was estimated at 10,737 living persons (95% confidence interval (CI): 9,744-11,806), including 5,054 undiagnosed, in Denmark and 16,124 (95% CI: 13,639-18,978), including 10,580 undiagnosed, in Sweden.ConclusionsThe reporting of HCV cases in Denmark and Sweden was different. For Denmark, the estimated hidden population was larger than the current national estimate, whereas in Sweden the estimate was in line with the latest published numbers.

[From treating in the dark towards eliminating hepatitis C].

Before the hepatitis C virus (HCV) was identified, patients with hepatitis C were treated with interferon. Alanine aminotranferase levels decreased in 25-50% of treated patients, but only 10-20% had been cured, i.e. became HCV-RNA-negative. Cure rates were improved to 40-60% by prolonging the duration of therapy and adding ribavirin, but it was not until the introduction of direct acting antivirals, that a cure for all patients was achieved. The time is now to eliminate hepatitis C, and in this review we argue, that it will require outreach and point-of-care testing and treating, but we expect Denmark to fulfil the WHO elimination goals before 2030.

Characterization of a Novel Hepatitis C Virus Genotype 1 Subtype from a Patient Failing 4 Weeks of Glecaprevir-Pibrentasvir Treatment.

Limited information is available in relation to surveillance, genotyping, genome sequences, and treatment outcomes for rare hepatitis C virus variants. Here, we have characterized a novel subtype of major hepatitis C virus genotype 1, which was deep sequenced before and after treatment failure with 4 weeks of glecaprevir and pibrentasvir.

Emergency department testing is feasible but ineffective to eliminate hepatitis C in Denmark.

BACKGROUND: As direct-acting antiviral treatment for hepatitis C virus (HCV) is widely available in Denmark, the hindrance to achieving elimination lies in identifying infections. Effective identification relies on screening in high-risk populations. Here, we report the outcomes of a risk-based, point-of-care (POC) screening strategy in a Danish emergency department (ED). METHODS: During a three-month period, ED patients at Odense University Hospital were screened for risk factors and offered POC HCV-antibody (HCV-Ab) testing. Reactive results were followed up by confirmatory venepuncture testing. The main outcome measure was prevalence of HCV-antibodies. Secondary outcome measures were prevalence of risk factors and an evaluation of feasibility of ED screening. RESULTS: During study times, 1831 (55.7%) of 3288 presentations to the ED were eligible for screening. Six hundred and seventy-three (36.8%) were approached, of which 514 (28.1%) participated and 159 (8.7%) declined. Of 514 participants, 339 (66%) reported one or more risk factors, and 489 (95.1%) underwent HCV-Ab testing. Four (0.8%) had a reactive HCV-Ab test. No active infections of HCV were found. The risk factor of having injected drugs was present in all HCV-Ab positive patients. Compared to participants, patients who could not be approached had a lower prevalence of previously diagnosed hepatitis C- and risk-factor-associated diagnoses. CONCLUSIONS: The risk factor of injecting drug use had the highest yield for HCV-Ab positivity. Additional risk factors did not contribute to case-finding. This screening strategy was feasible but ineffective. Further testing strategies will be necessary to identify the remaining hepatitis C patients in Denmark.

Inferior cure rate in pilot study of 4-week glecaprevir/pibrentasvir treatment with or without ribavirin of chronic hepatitis C.

BACKGROUND & AIMS: Shortening the treatment duration for chronic hepatitis C may increase feasibility and reduce the cost of cure. The aims of this study were to compare 4 weeks of glecaprevir/pibrentasvir (GLE/PIB) treatment with and without ribavirin for patients with chronic hepatitis C and favourable baseline characteristics and to monitor the development of resistance-associated substitutions (RAS) and re-treatment outcomes if treatment failed. METHODS: We performed an open-label single-centre randomized controlled trial, in which patients with chronic hepatitis C were randomized 1:1 to GLE/PIB ± ribavirin, stratified by genotype 3. The main inclusion criteria were treatment-naive patients, aged 18-49 with all genotypes accepted, and absence of liver fibrosis, determined by liver stiffness measurement less than 8 kPa. Viral genome sequences were determined by deep sequencing at baseline and at the time of relapse. RESULTS: A total of 32 patients started treatment. Sustained virological response at week 12 (SVR12) was 59% (10/17) for GLE/PIB without ribavirin and 73% (11/15) for GLE/PIB with ribavirin. Drug target-specific NS5A RAS were detected at baseline for 45% (5/11) of patients with treatment failure and for 14% (3/21) of patients who achieved SVR12. Ten failure patients were retreated 12 weeks with sofosbuvir-based regimens; all have been cured. CONCLUSIONS: In this pilot study of 4-week treatment with GLE/PIB with and without ribavirin, we found that baseline RAS were more frequent in patients with virological failure. Development of RAS did occur after short treatment but did not result in retreatment failure with a different regimen. EudraCT no: 2017-005179-21.

Presence of interferon-λ 4, male gender, absent/mild steatosis and low viral load augment antibody levels to hepatitis C virus.

OBJECTIVES: Despite recombinant interferon-λ 4 (IFN-λ4) demonstrating anti-viral activity in vitro and the ancestral functional gene (IFNL4) being conserved in all other primates, there has been speculation that IFN-λ4 may be detrimental in humans. In light of recent rekindled interest in humoral immunity, this study aimed at evaluating the impact of baseline characteristics, including IFNL4, on antibody levels to hepatitis C virus (HCV). MATERIALS AND METHODS: Pretreatment sera from 279 well-characterized North European Caucasians with chronic HCV genotype 2 or 3 infection having undergone liver biopsy were analyzed regarding IFNL4 (rs12979860) and anti-HCV antibody levels using a commercially available assay. RESULTS: Patients producing IFN-λ4 had higher signal to cut-off (S/CO) anti-HCV antibody ratios as compared with those lacking IFN-λ4 (IFNL4rs12979860 CT/TT versus CC, p<.0001, Mann-Whitney U-test). Additionally, in univariate analyses S/CO was significantly higher in men than women (p<.001), as well as in patients with absent/mild interface hepatitis (Ishak grade 0-2 versus 3-4, p = .009), and absent/mild steatosis (grade 0-1 versus 2-3, p = .0005). Also, an inverse correlation with HCV RNA level (rs= -0.14, p = .02) was noted. In multivariate analysis IFN-λ4, gender, steatosis and viral load remained independently associated. CONCLUSIONS: To our knowledge, this is the first report that demonstrates that the ability to produce IFN-λ4, in addition to male gender, absent/mild steatosis, and lower viral load, augments antibody levels against HCV. This indicates that IFN-λ4 may be associated with T helper cell 2 (Th2) immune skewing, which might have clinical implications beyond HCV infection. ClinicalTrials.gov Identifier: NCT00143000.

Global evolutionary analysis of chronic hepatitis C patients revealed significant effect of baseline viral resistance, including novel non-target sites, for DAA-based treatment and retreatment outcome.

Direct-acting antivirals (DAAs) have proven highly effective against chronic hepatitis C virus (HCV) infection. However, some patients experience treatment failure, associated with resistance-associated substitutions (RASs). Our aim was to investigate the complete viral coding sequence in hepatitis C patients treated with DAAs to identify RASs and the effects of treatment on the viral population. We selected 22 HCV patients with sustained virologic response (SVR) to match 21 treatment-failure patients in relation to HCV genotype, DAA regimen, liver cirrhosis and previous treatment experience. Viral-titre data were compared between the two patient groups, and HCV full-length open reading frame deep-sequencing was performed. The proportion of HCV NS5A-RASs at baseline was higher in treatment-failure (82%) than matched SVR patients (25%) (p = .0063). Also, treatment failure was associated with slower declines in viraemia titres. Viral population diversity did not differ at baseline between SVR and treatment-failure patients, but failure was associated with decreased diversity probably caused by selection for RAS. The NS5B-substitution 150V was associated with sofosbuvir treatment failure in genotype 3a. Further, mutations identified in NS2, NS3-helicase and NS5A-domain-III were associated with DAA treatment failure in genotype 1a patients. Six retreated HCV patients (35%) experienced 2nd treatment failure; RASs were present in 67% compared to 11% with SVR. In conclusion, baseline RASs to NS5A inhibitors, but not virus population diversity, and lower viral titre decline predicted HCV treatment failure. Mutations outside of the DAA targets can be associated with DAA treatment failure. Successful DAA retreatment in patients with treatment failure was hampered by previously selected RASs.