Spontaneous viral clearance following acute hepatitis C infection: a systematic review of longitudinal studies

Prevalence of diagnosed HIV infection among persons with hepatitis C virus infection: England, 2008-2014

OBJECTIVES

In persons with hepatitis C virus (HCV) infection, HIV coinfection leads to faster progression to advanced liver disease. The aim of our study was to estimate diagnosed HIV prevalence among people with evidence of current HCV infection (polymerase chain reaction positive) and examine predictors of coinfection.

METHODS

Adults (≥ 15 years old) with a current HCV infection reported to the Public Health England (PHE) sentinel surveillance of blood-borne viruses were linked to the PHE national HIV database using a deterministic methodology. Descriptive and multivariate analyses were conducted.

RESULTS

Between 2008 and 2014, 5.0% (999/20 088) of adults with a current HCV infection were diagnosed with HIV coinfection. The majority acquired HIV through sex between men (441; 64.9%), followed by injecting drug use (153; 22.5%) and heterosexual contact (84; 12.4%). Of persons who were coinfected, 65.5% had been diagnosed with HIV infection > 6 months before their HCV diagnosis, 41.4% of whom had a negative anti-HCV test between their HIV and HCV diagnoses. In a multivariable model among persons with current HCV infection, an HIV diagnosis was more likely among men [adjusted odds ratio (aOR) 3.29; 95% confidence interval (CI) 2.60-4.16] and persons of black ethnicity (aOR 3.19; 95% CI 1.36-7.46), and less likely among older adults (aOR 0.85 per 10-year increase; 95% CI 0.79-0.92) and persons of Asian ethnicity (aOR 0.59; 95% CI 0.41-0.86).

CONCLUSIONS

Our results indicate that the majority of diagnosed HIV and current HCV coinfections are among men who have sex with men. Safer sex campaigns should include awareness of transmission of HCV among MSM living with HIV.

Hepatitis C virus infection spontaneous clearance: Has it been underestimated?

OBJECTIVES

Hepatitis C virus (HCV) clearance rate (f_clearance) is defined as the proportion of infected persons who will spontaneously clear their infection after acute infection. We aimed to estimate f_clearance using a novel approach that avoids limitations in existing estimates, and to clarify the link between f_clearance and HCV viremic rate-the latter being the proportion of RNA positivity among those antibody positive.

METHODS

A mathematical model was developed to describe HCV transmission. f_clearance was estimated by fitting the model to probability-based and nationally representative population-based data for Egypt (Egypt 2008 and Egypt 2015) and USA (NHANES A and NHANES B). Uncertainty and sensitivity analyses were conducted.

RESULTS

f_clearance was estimated at 39.9% (95% uncertainty interval (UI): 34.3%-46.4%) and 33.5% (95% UI: 29.2%-38.3%) for Egypt 2008 and Egypt 2015 data, respectively; and at 29.6% (23.0%-37.1%) and 39.9% (31.2%-51.0%) for NHANES A and NHANES B data, respectively. f_clearance was found related to HCV viremic rate through (approximately) the formula f_clearance=1.16 (1-HCV viremic rate). HCV viremic rate was higher with higher risk of HCV exposure. Robustness of results was demonstrated in uncertainty and sensitivity analyses.

CONCLUSION

One-third of HCV-infected persons clear their infection spontaneously, higher than earlier estimates-the immune-system capacity to clear HCV infection may have been underestimated.

Behavioural, not biological, factors drive the HCV epidemic among HIV-positive MSM: HCV and HIV modelling analysis including HCV treatment-as-prevention impact

Background

Uncertainty surrounds why hepatitis C virus (HCV) is concentrated among HIV-positive men who have sex with men (MSM). We used mathematical modelling to explore reasons for these infection patterns, and implications for HCV treatment-as-prevention.

Methods

Using a joint MSM HIV/HCV transmission model parameterized with UK behavioural data, we considered how biological (heightened HCV infectivity and reduced spontaneous clearance among HIV-positive MSM) and/or behavioural factors (preferential sexual mixing by HIV status and risk heterogeneity) could concentrate HCV infection in HIV-positive MSM as commonly observed (5-20 times the HCV prevalence in HIV-negative MSM; defined as the HCV ratio). We explored how HCV treatment-as-prevention impact varies under differing HCV ratios.

Results

Biological factors produced low HCV ratios (< 3), not explaining the skewed epidemic. However, combining preferential mixing by HIV status with sexual risk behaviour heterogeneity produced high HCV ratios (> 10) that were highly sensitive to both factors. Irrespective of the HCV ratio or behavioural/biological factors, HCV treatment of HIV-diagnosed MSM markedly reduced the HCV prevalence among HIV-positive MSM, but less impact was achieved among all MSM for lower HCV ratios.

Conclusions

Sexual behaviour patterns likely drive observed HCV infection patterns among HIV-positive MSM. Changes in these patterns could disseminate HCV amongst HIV-negative MSM, limiting the impact of targeting HCV treatment to HIV-diagnosed MSM.

Barriers to and facilitators of hepatitis C virus screening and testing: A scoping review

BACKGROUND

As part of the global effort to eliminate hepatitis C virus (HCV), it is important to understand the barriers to and facilitators of HCV screening and testing.

OBJECTIVE

To examine the barriers and facilitators experienced by health care providers offering HCV screening and testing and patients seeking HCV testing.

METHODS

A literature search was conducted using Embase, Medline and Scopus databases to collect studies published between January 2012 and July 2017. We extracted the following data: author, year of publication, study design, population, setting, country, method of data collection, and knowledge and awareness outcomes.

RESULTS

A total of 16 articles were identified. Barriers to HCV screening and testing among patients included low self-perceived risk of acquiring HCV, perceived stigma and fear of a positive result. Facilitators of HCV screening and testing, as reported by patients, included increased knowledge of transmission and manifestations of HCV infection and having HCV testing included as part of routine care with or without HIV testing. Barriers to offering HCV screening and testing included time constraints, lack of specific knowledge about HCV and discomfort in asking about risk behaviours. Facilitators of offering HCV screening and testing included testing reminders and working in locations with a higher HCV caseload.

CONCLUSION

Lack of knowledge and fear of stigma and discrimination remain barriers to HCV testing at the patient level and lack of time, knowledge and discomfort in asking about risk behaviours remain barriers to offering HCV testing by health care providers. This identifies potential areas for future public health action.

Modelling how responsiveness to interferon improves interferon-free treatment of hepatitis C virus infection

Direct-acting antiviral agents (DAAs) for hepatitis C treatment tend to fare better in individuals who are also likely to respond well to interferon-alpha (IFN), a surprising correlation given that DAAs target specific viral proteins whereas IFN triggers a generic antiviral immune response. Here, we posit a causal relationship between IFN-responsiveness and DAA treatment outcome. IFN-responsiveness restricts viral replication, which would prevent the growth of viral variants resistant to DAAs and improve treatment outcome. To test this hypothesis, we developed a multiscale mathematical model integrating IFN-responsiveness at the cellular level, viral kinetics and evolution leading to drug resistance at the individual level, and treatment outcome at the population level. Model predictions quantitatively captured data from over 50 clinical trials demonstrating poorer response to DAAs in previous non-responders to IFN than treatment-naïve individuals, presenting strong evidence supporting the hypothesis. Model predictions additionally described several unexplained clinical observations, viz., the percentages of infected individuals who 1) spontaneously clear HCV, 2) get chronically infected but respond to IFN-based therapy, and 3) fail IFN-based therapy but respond to DAA-based therapy, resulting in a comprehensive understanding of HCV infection and treatment. An implication of the causal relationship is that failure of DAA-based treatments may be averted by adding IFN, a strategy of potential use in settings with limited access to DAAs. A second, wider implication is that individuals with greater IFN-responsiveness would require shorter DAA-based treatment durations, presenting a basis and a promising population for response-guided therapy.

Management of acute HCV infection in the era of direct-acting antiviral therapy

The management of acute HCV infection has not been standardized following the availability of direct-acting antiviral agents (DAAs) for chronic HCV infection, and substantial uncertainty exists regarding the optimal treatment regimen and duration. Despite the lack of direct evidence, the 2016 American Association for the Study of Liver Diseases (AASLD)-Infectious Diseases Society of America (IDSA) guidelines supported "the same regimens for acute HCV as recommended for chronic HCV infection … owing to high efficacy and safety", whereas the 2016 European Association for the Study of the Liver (EASL) guidelines recommended sofosbuvir-ledipasvir, sofosbuvir-velpatasvir or sofosbuvir plus daclatasvir for 8 weeks in acute HCV infection, with a longer duration of 12 weeks recommended for those infected with HIV and/or baseline HCV RNA levels >1,000,000 IU/ml. This Review outlines the epidemiology, natural history and diagnosis of acute HCV infection and provides contemporary information on DAAs for acute and recent HCV infection. The Review also discusses the 2016 AASLD-IDSA and EASL recommendations for acute HCV infection management in light of available evidence and highlights key differences in study populations and design that influence interpretation. We focus on populations at high risk of HCV transmission and acquisition, including people who inject drugs and HIV-positive men who have sex with men, and highlight the potential effects of diagnosis and treatment of acute HCV infection in contributing to HCV elimination.

A Surveillance-Based Hepatitis C Care Cascade, New York City, 2017

OBJECTIVES

The care cascade, a method for tracking population-level progression from diagnosis to cure, is an important tool in addressing and monitoring the hepatitis C virus (HCV) epidemic. However, little agreement exists on appropriate care cascade steps or how best to measure them. The New York City (NYC) Department of Health and Mental Hygiene (DOHMH) sought to construct a care cascade by using laboratory surveillance data with clinically relevant categories that can be readily updated over time.

METHODS

We identified all NYC residents ever reported to the DOHMH surveillance registry with HCV through June 30, 2017 (n = 175 896). To account for outmigration, death, or treatment before negative RNA results became reportable to the health department, we limited the population to people with any test reported since July 1, 2014. Of these residents, we identified the proportion with a reported positive RNA test and estimated the proportion treated and cured since July 2014 by using DOHMH-developed surveillance-based algorithms.

RESULTS

Of 78 886 NYC residents ever receiving a diagnosis of HCV and tested since July 1, 2014, a total of 70 397 (89.2%) had ever been reported as RNA positive through June 30, 2017; 36 875 (46.7%) had initiated treatment since July 1, 2014, and 23 766 (30.1%) appeared cured during the same period.

CONCLUSION

A substantial gap exists between confirming HCV infection and initiating treatment, even in the era of direct-acting antivirals. Using this cascade, we will monitor progress in improved treatment and cure of HCV in NYC.

Modeling how reversal of immune exhaustion elicits cure of chronic hepatitis C after the end of treatment with direct-acting antiviral agents

A fraction of chronic hepatitis C patients treated with direct‐acting antivirals (DAAs) achieved sustained virological responses (SVR), or cure, despite having detectable viremia at the end of treatment (EOT). This observation, termed EOT⁺/SVR, remains puzzling and precludes rational optimization of treatment durations. One hypothesis to explain EOT⁺/SVR, the immunologic hypothesis, argues that the viral decline induced by DAAs during treatment reverses the exhaustion of cytotoxic T lymphocytes (CTLs), which then clear the infection after treatment. Whether the hypothesis is consistent with data of viral load changes in patients who experienced EOT⁺/SVR is unknown. Here, we constructed a mathematical model of viral kinetics incorporating the immunologic hypothesis and compared its predictions with patient data. We found the predictions to be in quantitative agreement with patient data. Using the model, we unraveled an underlying bistability that gives rise to EOT⁺/SVR and presents a new avenue to optimize treatment durations. Infected cells trigger both activation and exhaustion of CTLs. CTLs in turn kill infected cells. Due to these competing interactions, two stable steady states, chronic infection and viral clearance, emerge, separated by an unstable steady state with intermediate viremia. When treatment during chronic infection drives viremia sufficiently below the unstable state, spontaneous viral clearance results post‐treatment, marking EOT⁺/SVR. The duration to achieve this desired reduction in viremia defines the minimum treatment duration required for ensuring SVR, which our model can quantify. Estimating parameters defining the CTL response of individuals to HCV infection would enable the application of our model to personalize treatment durations.

Assessing hepatitis C spontaneous clearance and understanding associated factors-A systematic review and meta-analysis

New advances in the treatment of hepatitis C provide high levels of sustained viral response but their expense limits availability in publicly funded health systems. The aim of this review was to estimate the proportion of patients who will spontaneously clear HCV, to identify factors that are associated with clearance and to support better targeting of directly acting antivirals. We searched Ovid EMBASE, Ovid MEDLINE and PubMed from 1 January 1994 to 30 June 2015 for studies reporting hepatitis C spontaneous clearance and/or demographic, clinical and behavioural factors associated with clearance. We undertook meta-analyses to estimate the odds of clearance for each predictor. Forty-three studies met the inclusion criteria, representing 20 110 individuals, and 6 of these studies included sufficient data to estimate spontaneous clearance. The proportion achieving clearance within 3, 6, 12 and 24 months following infection were, respectively, 19.8% (95% CI: 2.6%-47.5%), 27.9% (95% CI: 17.2%-41.8%), 36.1% (95% CI: 23.5%-50.9%) and 37.1% (95% CI: 23.7%-52.8%). Individuals who had not spontaneously cleared by 12 months were unlikely to do so. The likelihood of spontaneous clearance was lower in males and individuals with HIV co-infection, the absence of HBV co-infection, asymptomatic infection, black or nonindigenous race, nongenotype 1 infection, older age and alcohol or drug problems. This study suggests that patients continue to spontaneously clear HCV for at least 12 months following initial infection. However, injecting drug users are comparatively less likely to achieve clearance; thus, they should be considered a priority for early treatment given the continuing risks that these individuals pose for onwards transmission.

Should organs from hepatitis C-positive donors be used in hepatitis C-negative recipients for liver transplantation?

Given the scarcity of donated organs and the frequency of death on the waiting list, strategies that could improve the available supply of high-quality liver grafts are much needed. Direct-acting antiviral agent (DAA) regimens have proved to be highly effective to treat hepatitis C virus (HCV), even in the setting of posttransplantation. The question arises as to whether transplant communities should consider the utilization of HCV-positive donors into HCV-negative recipients. This review summarizes risk of transmission, treatment options with success rate, and ethical considerations for usage of HCV-positive donors. Liver Transplantation 24 831-840 2018 AASLD.

Hepatitis C Virus Infection and Vaccine Development

In the twenty-seven years since the discovery of hepatitis C virus (HCV) the majority of individuals exposed to HCV establish a persistent infection, which is a leading cause of chronic liver disease, cirrhosis and hepatocellular carcinoma. In developed nations, the cure rates of HCV infection could be over 90% with direct-acting antiviral (DAA) regimens, which has made the great progress in global eradication. However, the cost of these treatments is so expensive that the patients in developing nations, where the disease burden is the most severe, could not afford it, which highly restricted its access. Additionally, the largely asymptomatic nature of infection facilitates continued transmission in risk groups due to limited surveillance. Consequently a protective vaccine and likely emergence of drug-resistant viral variants call for further studies of HCV biology. In the current review, the development and the progress of preventive and therapeutic vaccines against the HCV have been reviewed in the context of peptide vaccines, recombinant protein vaccines, HCV-like particle, DNA vaccines and viral vectors expressing HCV genes.

Impact of current and scaled-up levels of hepatitis C prevention and treatment interventions for people who inject drugs in three UK settings-what is required to achieve the WHO's HCV elimination targets?

AIMS

To estimate the impact of existing high-coverage needle and syringe provision (HCNSP, defined as obtaining more than one sterile needle and syringe per injection reported) and opioid substitution therapy (OST) on hepatitis C virus (HCV) transmission among people who inject drugs (PWID) in three UK settings and to determine required scale-up of interventions, including HCV treatment, needed to reach the World Health Organization (WHO) target of reducing HCV incidence by 90% by 2030.

DESIGN

HCV transmission modelling using UK empirical estimates for effect of OST and/or HCNSP on individual risk of HCV acquisition.

SETTING AND PARTICIPANTS

Three UK cities with varying chronic HCV prevalence (Bristol 45%, Dundee 26%, Walsall 19%), OST (72-81%) and HCNSP coverage (28-56%).

MEASUREMENTS

Relative change in new HCV infections throughout 2016-30 if current interventions were stopped. Scale-up of HCNSP, OST and HCV treatment required to achieve the WHO elimination target.

FINDINGS

Removing HCNSP or OST would increase the number of new HCV infections throughout 2016 to 2030 by 23-64 and 92-483%, respectively. Conversely, scaling-up these interventions to 80% coverage could achieve a 29 or 49% reduction in Bristol and Walsall, respectively, whereas Dundee may achieve a 90% decrease in incidence with current levels of intervention because of existing high levels of HCV treatment (47-58 treatments per 1000 PWID). If OST and HCNSP are scaled-up, Walsall and Bristol can achieve the same impact by treating 14 or 40 per 1000 PWID annually, respectively (currently two and nine treatments per 1000 PWID), while 18 and 43 treatments per 1000 PWID would be required if OST and HCNSP are not scaled-up.

CONCLUSIONS

Current opioid substitution therapy and high-coverage needle and syringe provision coverage is averting substantial hepatitis C transmission in the United Kingdom. Maintaining this coverage while getting current drug injectors onto treatment can reduce incidence by 90% by 2030.

Estimates of state-level chronic hepatitis C virus infection, stratified by race and sex, United States, 2010

Background

Hepatitis C virus (HCV) is the most common blood-borne viral infection in the United States. Previously, we used data from the National Health and Nutrition Examination Survey (NHANES) and mortality data from the National Vital Statistics System (NVSS) to estimate the prevalence of HCV antibodies (anti-HCV) and HCV RNA among all U.S. states. However, demographic differences in HCV burden at the state-level have not been systematically described. This analysis quantified the HCV burden stratified by sex and race (and associated disparities) for each U.S. state.

Methods

Building on our previous method, we used three publicly available data sources to estimate HCV RNA prevalence among noninstitutionalized adults stratified by sex and race group. We used a small-area estimation approach that included direct standardization of NHANES demographic data with logistic regression modeling of HCV-related mortality data as an adjustment factor to estimate the state-level prevalence and total persons with chronic HCV infection for sex and race groups in all U.S. states.

Results

Nationally, males had an estimated HCV RNA prevalence of 1.56% (95% CI: 1.37–1.84%) and females had a prevalence of 0.75% (95% CI: 0.63–0.96%). Stratified by race, national estimated prevalence of HCV RNA was highest among non-Hispanic black (2.43, 95% CI: 2.10–2.90%), followed by non-Hispanic white (1.05, 95% CI: 0.90–1.27%) and Hispanic/other (0.74, 95% CI: 0.59–1.04%). Males in most jurisdictions (41/51) have an HCV RNA prevalence that is between 1.5 and 2.5 times higher than their female counterparts.

Conclusions

HCV infection disparities by sex are mostly consistent across the country. However, race differences in HCV infection differ by state and tailored prevention and treatment efforts specific to the local HCV epidemic are needed to reduce race disparities.

Electronic supplementary material

The online version of this article (10.1186/s12879-018-3133-6) contains supplementary material, which is available to authorized users.

Eliminating HIV/HCV co-infection in gay and bisexual men: is it achievable through scaling up treatment?

INTRODUCTION

Broad availability of direct-acting antiviral therapy for hepatitis C virus (HCV) raises the possibility that HCV prevalence and incidence can be reduced through scaling-up treatment, leading to the elimination of HCV. High rates of linkage to HIV care among HIV-infected gay and bisexual men may facilitate high uptake of HCV treatment, possibly making HCV elimination more achievable in this group. Areas covered: This review covers HCV elimination in HIV-infected gay and bisexual men, including epidemiology, spontaneous clearance and long term sequelae in the absence of direct-acting antiviral therapy; direct-acting antiviral therapy uptake and effectiveness in this group; HCV reinfection following successful treatment; and areas for further research. Expert commentary: Early data from the direct-acting antiviral era suggest that treatment uptake is increasing among HIV infected GBM, and SVR rates are very promising. However, in order to sustain current treatment rates, additional interventions at the behavioral, physician, and structural levels may be required to increase HCV diagnosis, including prompt detection of HCV reinfection. Timely consideration of these issues is required to maximize the population-level impact of HCV direct-acting antiviral therapy. Potential HCV transmissions from HIV-uninfected GBM, across international borders, and from those who are not GBM also warrant consideration.

Genotyping & diagnostic methods for hepatitis C virus: A need of low-resource countries

Hepatitis C virus (HCV) infection is a blood borne and transfusion-transmitted infection (TTI). It has emerged as one of the major health challenges worldwide. In India, around 12-18 million peoples are infected with HCV, but in terms of prevalence percentage, its looks moderate due to large population. The burden of the HCV infection increases due to lack of foolproof screening of blood and blood products before transfusion. The qualified screening and quantification of HCV play an important role in diagnosis and treatment of HCV-related diseases. If identified early, HCV infection can be managed and treated by recently available antiviral therapies with fewer side effects. However, its identification at chronic phase makes its treatment very challenging and sometimes ineffective. The drugs therapy for HCV infection treatment is also dependent on its genotype. Different genotypes of HCV differ from each other at genomic level. The RNA viruses (such as HCV) are evolving perpetually due to interaction and integration among people from different regions and countries which lead to varying therapeutic response in HCV-infected patients in different geographical regions. Therefore, proper diagnosis for infecting virus and then exact determination of genotype become important for targeted treatment. This review summarizes the general information on HCV, and methods used for its diagnosis and genotyping.

Innate and Adaptive Immune Responses in Chronic HCV Infection

Hepatitis C virus (HCV) remains a public health problem of global importance, even in the era of potent directly-acting antiviral drugs. In this chapter, I discuss immune responses to acute and chronic HCV infection. The outcome of HCV infection is influenced by viral strategies that limit or delay the initiation of innate antiviral responses. This delay may enable HCV to establish widespread infection long before the host mounts effective T and B cell responses. HCV's genetic agility, resulting from its high rate of replication and its error prone replication mechanism, enables it to evade immune recognition. Adaptive immune responses fail to keep up with changing viral epitopes. Neutralizing antibody epitopes may be hidden by decoy structures, glycans, and lipoproteins. T cell responses fail due to changing epitope sequences and due to exhaustion, a phenomenon that may have evolved to limit immune-mediated pathology. Despite these difficulties, innate and adaptive immune mechanisms do impact HCV replication. Immune-mediated clearance of infection is possible, occurring in 20-50% of people who contract the disease. New developments raise hopes for effective immunological interventions to prevent or treat HCV infection.

HIV treatment as prevention among people who inject drugs - a re-evaluation of the evidence

Background

Population-level associations between community measures of HIV viral load and HIV incidence have been interpreted as evidence for HIV anti-retroviral treatment (ART) as prevention among people who inject drugs (PWID). However, investigation of concurrent HCV and HIV incidence trends allows examination of alternative explanations for the fall in HIV incidence. We estimate the contribution of ART and reductions in injecting risk for reducing HIV incidence in Vancouver between 1996 and 2007.

Methods

A deterministic model of HIV and HCV transmission among PWID was calibrated to the baseline (1996) HIV and HCV epidemic among PWID in Vancouver. While incorporating parameter uncertainty, the model projected what levels of ART protection and decreases in injecting risk could reproduce the observed reduction in HIV and HCV incidence for 1996-2007, and so what impact would have been achieved with just ART or just reductions in injecting risk.

Results

Model predictions suggest the estimated reduction (84%) in HCV incidence for 1996-2007 required a 59% (2.5-97.5 percentile range 49-76%) reduction in injecting risk, which accounted for nine-tenths of the observed decrease in HIV incidence; the remainder was achieved with a moderate ART efficacy for reducing sexual HIV infectivity (70%, 51-89%) and an uncertain ART efficacy for reducing injection-related HIV infectivity (44%, 0-96%). Despite this uncertainty, projections suggest that the decrease in injecting risk reduced HIV incidence by 76% (63-85%) and ART further reduced HIV incidence by 8% (2-19%), or on its own by 3% (-34-37%).

Conclusions

Observed declines in HIV incidence in Vancouver between 1996 and 2007 should be seen as a success for intensive harm reduction, whereas ART probably played a small role.

Healing livers, saving lives: Hepatitis C screening in an era of cure

Chronic hepatitis C affects more than 3 million people in the United States. In the past, drug therapy with interferon and ribavirin resulted in low overall cure rates and early discontinuation due to adverse reactions. The new direct-acting antivirals offer not only a shorter duration of treatment with fewer adverse reactions, but greatly improved overall cure rates as high as 96%. Updated national screening recommendations (including a one-time screening for patients born between 1945 and 1965), combined with timely referral and treatment, offer a prime opportunity for healthcare providers to improve public health outcomes and reduce healthcare costs.

Cost-effectiveness of hepatitis C screening and treatment linkage intervention in US methadone maintenance treatment programs

BACKGROUND

We evaluated the cost-effectiveness of a hepatitis C (HCV) screening and active linkage to care intervention in US methadone maintenance treatment (MMT) patients using data from a randomized trial conducted in New York City and San Francisco.

METHODS

We used a decision analytic model to compare 1) no intervention; 2) HCV screening and education (control); and 3) HCV screening, education, and care coordination (active linkage intervention). We also explored an alternative strategy wherein HCV/HIV co-infected participants linked elsewhere. Trial data include population characteristics (67% male, mean age 48, 58% HCV infected) and linkage rates. Data from published sources include treatment efficacy and HCV re-infection risk. We projected quality-adjusted life years (QALYs) and lifetime medical costs using an established model of HCV (HEP-CE). Incremental cost-effectiveness ratios (ICERs) are in 2015 US$/QALY discounted 3% annually.

RESULTS

The control strategy resulted in a projected 35% linking to care within 6 months and 31% achieving sustained virologic response (SVR). The intervention resulted in 60% linking and 54% achieving SVR with an ICER of $24,600/QALY compared to no intervention from the healthcare sector perspective and was a more efficient use of resources than the control strategy. The intervention had an ICER of $76,500/QALY compared to the alternative strategy. From a societal perspective, the intervention had a net monetary benefit of $511,000-$975,600.

CONCLUSIONS

HCV care coordination interventions that include screening, education and active linkage to care in MMT settings are likely cost-effective at a conventional $100,000/QALY threshold for both HCV mono-infected and HIV co-infected patients.

Diagnosis and Management of Hepatitis C Infection in Primary Care Settings

Hepatitis C virus (HCV) infection is a significant health problem worldwide, and is the leading cause of cirrhosis, hepatocellular carcinoma, and liver transplantation in the United States. The management of HCV has changed significantly over the last 5 years, as treatments have become simpler and more efficacious. Medication efficacy is now greater than 90%, with a high barrier to resistance and few side effects. This review is a collaboration between primary care and hepatology providers to explore all aspects of HCV management: acute versus chronic HCV infection, transmission and testing, and diagnosis and treatment. Specific medications for the treatment of HCV infection are considered, and patient and medication factors including genotype, liver disease status, and comorbidities affecting medication choice are discussed. This is a new era for the management of HCV infection, and interested primary care physicians, family doctors, and general internists can be at the forefront of diagnosis, management, and treatment of HCV.

Should we treat acute hepatitis C? A decision and cost-effectiveness analysis

It is not standard practice to treat patients with acute hepatitis C virus (HCV) infection. However, as the incidence of HCV in the United States continues to rise, it may be time to re-evaluate acute HCV management in the era of direct-acting antiviral (DAA) agents. In this study, a microsimulation model was developed to analyze the trade-offs between initiating HCV therapy in the acute versus chronic phase of infection. By simulating the lifetime clinical course of patients with acute HCV infection, we were able to project long-term outcomes such as quality-adjusted life years (QALYs) and costs. We found that treating acute HCV versus deferring treatment until the chronic phase increased QALYs by 0.02 and increased costs by $483 in patients not at risk of transmitting HCV. The resulting incremental cost-effectiveness ratio was $19,991 per QALY, demonstrating that treatment of acute HCV was cost-effective using a willingness-to-pay threshold of $100,000 per QALY. In patients at risk of transmitting HCV, treating acute HCV became cost-saving, increasing QALYs by 0.03 and decreasing costs by $3,655.

CONCLUSION

Immediate treatment of acute HCV with DAAs can improve clinical outcomes and be highly cost-effective or cost-saving compared with deferring treatment until the chronic phase of infection. If future studies continue to demonstrate effective HCV cure with shorter 6-week treatment duration, then it may be time to revisit current HCV guidelines to incorporate recommendations that account for the clinical and economic benefits of treating acute HCV in the era of DAAs. (Hepatology 2018;67:837-846).

Hepatitis C virus-induced natural killer cell proliferation involves monocyte-derived cells and the OX40/OX40L axis

BACKGROUND & AIMS

Natural killer (NK) cells are found at increased frequencies in patients with hepatitis C virus (HCV). NK cell activation has been shown to correlate with HCV clearance and to predict a favourable treatment response. The aim of our study was to dissect mechanisms leading to NK cell activation and proliferation in response to HCV.

METHODS

NK cell phenotype, proliferation, and function were assessed after the 6-day co-culture of human peripheral blood mononuclear cells with either HCV replicon-containing HuH6 hepatoblastoma cells or HCV-infected HuH7.5 cells. The results obtained were confirmed by immunohistochemistry of liver biopsies from patients with HCV and from HCV-negative controls.

RESULTS

In HCV-containing co-cultures, a higher frequency of NK cells upregulated the expression of the high-affinity IL-2 receptor chain CD25, proliferated more rapidly, and produced higher amounts of interferon γ compared with NK cells from control co-cultures. This NK cell activation was dependent on IL-2, cell-cell contact-mediated signals, and HCV replicon-exposed monocytes. The tumour necrosis factor-receptor superfamily member OX40 was induced on the activated CD25^± NK cell subset and this induction was abrogated by the depletion of CD14⁺ monocytes. Moreover, OX40L was upregulated on CD14^± monocyte-derived cells co-cultured with HCV-containing cells and also observed in liver biopsies from patients with HCV. Importantly, blocking of the OX40/OX40L interaction abolished both NK cell activation and proliferation.

CONCLUSIONS

Our results uncover a previously unappreciated cell-cell contact-mediated mechanism of NK cell activation and proliferation in response to HCV, mediated by monocyte-derived cells and the OX40/OX40L axis. These results reveal a novel mode of crosstalk between innate immune cells during viral infection.

LAY SUMMARY

Using a cell-culture model of hepatitis C virus (HCV) infection, our study revealed that natural killer (NK) cells become activated and proliferate when they are co-cultured with HCV-containing liver cells. The mechanism of this activation involves crosstalk with other innate immune cells and a cell-cell contact interaction mediated by the cell surface molecules OX40 and OX40L. Our study reveals a novel pathway leading to NK cell proliferation and activation against virus-infected cells that might be of relevance in antiviral immunity.

Treatment of hepatitis C virus infection for adults and children: updated Swedish consensus guidelines 2017

AIM

Following the approval of two new therapeutic combinations within the European Union in 2017, the former Swedish recommendations for the treatment of hepatitis C virus (HCV) infection from 2016 were deemed in need of updating.

MATERIALS AND METHODS

An expert meeting to this end was held in Stockholm, Sweden in October 2017.

RESULTS AND CONCLUSIONS

An interferon-free combination of direct-acting antiviral agents is now recommended for all patients with chronic HCV infection, regardless of liver fibrosis stage, in order to limit morbidity and spread of the disease. An extended discussion of treatment for people who inject drugs in order to diminish transmission is included.

Model projections on the impact of HCV treatment in the prevention of HCV transmission among people who inject drugs in Europe

BACKGROUND & AIMS

Prevention of hepatitis C virus (HCV) transmission among people who inject drugs (PWID) is critical for eliminating HCV in Europe. We estimated the impact of current and scaled-up HCV treatment with and without scaling up opioid substitution therapy (OST) and needle and syringe programmes (NSPs) across Europe over the next 10 years.

METHODS

We collected data on PWID HCV treatment rates, PWID prevalence, HCV prevalence, OST, and NSP coverage from 11 European settings. We parameterised an HCV transmission model to setting-specific data that project chronic HCV prevalence and incidence among PWID.

RESULTS

At baseline, chronic HCV prevalence varied from <25% (Slovenia/Czech Republic) to >55% (Finland/Sweden), and <2% (Amsterdam/Hamburg/Norway/Denmark/Sweden) to 5% (Slovenia/Czech Republic) of chronically infected PWID were treated annually. The current treatment rates using new direct-acting antivirals (DAAs) may achieve observable reductions in chronic prevalence (38-63%) in 10 years in Czech Republic, Slovenia, and Amsterdam. Doubling the HCV treatment rates will reduce prevalence in other sites (12-24%; Belgium/Denmark/Hamburg/Norway/Scotland), but is unlikely to reduce prevalence in Sweden and Finland. Scaling-up OST and NSP to 80% coverage with current treatment rates using DAAs could achieve observable reductions in HCV prevalence (18-79%) in all sites. Using DAAs, Slovenia and Amsterdam are projected to reduce incidence to 2 per 100 person years or less in 10 years. Moderate to substantial increases in the current treatment rates are required to achieve the same impact elsewhere, from 1.4 to 3 times (Czech Republic and France), 5-17 times (France, Scotland, Hamburg, Norway, Denmark, Belgium, and Sweden), to 200 times (Finland). Scaling-up OST and NSP coverage to 80% in all sites reduces treatment scale-up needed by 20-80%.

CONCLUSIONS

The scale-up of HCV treatment and other interventions is needed in most settings to minimise HCV transmission among PWID in Europe.

LAY SUMMARY

Measuring the amount of HCV in the population of PWID is uncertain. To reduce HCV infection to minimal levels in Europe will require scale-up of both HCV treatment and other interventions that reduce injecting risk (especially OST and provision of sterile injecting equipment).

Three variants in the nicotinamide adenine dinucleotide phosphate oxidase complex are associated with HCV-related liver damage

Approximately 71 million people are chronically infected with the hepatitis C virus (HCV), a potentially lethal pathogen. HCV generates oxidative stress correlating with disease severity. HCV proteins increase reactive oxygen species production by stimulating nicotinamide adenine dinucleotide phosphate oxidase (NOX) activity. Reactive oxygen species are necessary for host defense and cell signaling; however, elevated NOX activity contributes to cancer, and NOX overexpression is associated with hepatic fibrosis. Our aim was to investigate whether single nucleotide polymorphisms (SNPs) in NOX family members are associated with HCV-related liver damage. Three hundred and thirty-one individuals of European ancestry and 90 individuals of African ancestry, all diagnosed with HCV, were genotyped for 243 tagSNPs in NOX enzymes and their regulatory factors. Pathology scores were available for 288 Caucasians and 71 Africans, and mortality status was determined for all subjects. SNPs were tested for association with pathology scores and as predictors of mortality. In Africans, homozygosity for the A allele of rs12753665 (neutrophil cytosolic factor 2) and homozygosity for the T allele of rs760519 (neutrophil cytosolic factor 4) were associated with and predictive of higher rates of advanced fibrosis and cirrhosis compared to other genotypes after controlling for age and sex. In Caucasians, homozygosity for the T allele of rs2292464 (dual oxidase 1) was associated with and predictive of decreased periportal inflammation after controlling for age and sex. No SNPs were significant predictors of mortality. Conclusion: In this exploratory study, three NOX-related polymorphisms in two ethnic groups were significantly associated with hepatic inflammation and fibrosis. Future studies investigating these SNPs in larger cohorts of patients with HCV are warranted. (Hepatology Communications 2017;1:973-982).

Genotype-related variations in proinflammatory and regulatory cytokine levels in treated and treatment-naive HCV-infected patients

Hepatitis C virus (HCV) modulates immune-related inflammatory responses to induce milder reactions leading to virus persistence. In this regard, the present study aimed to investigate the link between the HCV genotypes and the proinflammatory and regulatory cytokine levels. Ninety patients with hepatitis C infection (68 treatment-naive and 22 treated patients) and 76 healthy blood donors were studied. The serum levels of IFN-γ, IL-10, IL-17A, and IL-21 were measured by ELISA in the patients and healthy controls. IL-10, IL-17A, and IL-21 levels were significantly higher in HCV patients than in the healthy controls. The same cytokines were also higher in genotype 3a-infected patients compared with genotype 1a-infected patients. Interestingly, in treated patients, lower serum levels of IL-17A and IL-21 were detected in G3a-infected individuals, but not in those infected with G1a. G3a viral load displayed a significant correlation with IL-21 and IL-17A levels. In addition, G1a viral load correlated with IL-10 levels. In G3a-infected patients, a significant association was found between IL-17A serum levels and ALT. We found differences in IL-21 and IL-17A serum levels among HCV-infected patients which were genotype dependent. Since Th17-associated cytokines are associated with the progression of liver disease in HCV patients, IL-17A and IL-21 can be used as important biological markers for evaluating the immunopathogenesis of chronic hepatitis. Our results suggest that HCV G3a along with immune responses such as cytokines in HCV patients should be taken into account when interpreting clinical data and IFN-based therapeutic response.

Characterizing hepatitis C virus epidemiology in Egypt: systematic reviews, meta-analyses, and meta-regressions

Egypt is the most affected nation by hepatitis C virus (HCV) and needs a comprehensive characterization of HCV epidemiology to inform the scale-up of treatment and prevention programs. Systematic reviews, meta-analyses, and meta-regressions were conducted. A total of 25 incidence, 259 prevalence, and 47 genotype studies were identified. Incidence and prevalence levels were high across all populations. Genotype 4 accounted for 94.1% of infections with a relative Shannon Diversity Index of only 14.4%. Pooled mean HCV prevalence was estimated at 11.9% (95% CI = 11.1–12.6%) among the general population, 55.6% (95% CI = 49.4–61.7%) among populations at high risk, 14.3% (95% CI = 10.3–18.8%) among populations at intermediate risk, 56.0% (95% CI = 50.4–61.6%) among populations with liver-related conditions, and 35.0% (95% CI = 27.3–43.1%) among special clinical populations. Mean HCV viremic rate was estimated at 66.7% (95% CI = 61.7–71.5%). Meta-regression indicated 6% lower odds for HCV prevalence for each one-year increment in publication year (AOR = 0.94; 95% CI = 0.92–0.96). HCV prevalence is high with evidence for ongoing transmission mainly through healthcare. Genotype diversity is low with genotype 4 dominance. Two-thirds of antibody-positive Egyptians are chronically infected and need treatment. Clinical populations should be prioritized for screening. Despite the large-scale epidemic, prevalence appears to be declining rapidly consistent with a contracting epidemic.

Population-based estimate of hepatitis C virus prevalence in Ontario, Canada

Background

Hepatitis C virus (HCV) is the most burdensome infectious illness in Canada. Current screening strategies miss a significant proportion of cases, leaving many undiagnosed. Elevated HCV prevalence in those born between 1945 and 1965 has prompted calls for birth-cohort screening in this group. However, Canada lacks population-level data to support this recommendation. We performed a serosurvey to obtain population-based HCV prevalence estimates in Ontario residents born between 1945–1974, to generate evidence for birth-cohort screening recommendations.

Methods

We tested anonymized residual sera in five-year age-sex bands from Ontario for anti-HCV antibody. We performed descriptive epidemiological analysis and used a logistic regression model to determine HCV risk-factors.

Results

Of 10,006 sera analyzed, 155 (1.55%, 95% confidence interval (CI) 1.32, 1.81) were positive for HCV antibody. Individuals born between 1950–1964 had a significantly higher combined prevalence of 1.92% (95% CI 1.56, 2.34) compared to 1.14% (95% CI 0.69, 1.77) (p = 0.04) for those born between 1970–1974. For males, comprising 107/155 (69.03%) of positive samples, the highest prevalence was 3.00% (95% CI 1.95, 4.39) for the 1960–1964 birth-cohort. For females, the highest prevalence was 1.56% (95% CI 0.83, 2.65) for those born between 1955–1959. Male sex was significantly associated with positive HCV serostatus.

Interpretation

HCV prevalence in Ontario is highest among those in this birth cohort, and higher than previous estimates. The prevalence estimates presented in our study provide important data to underpin birth-cohort screening recommendations.

Cost-Effectiveness of One-Time Hepatitis C Screening Strategies Among Adolescents and Young Adults in Primary Care Settings

Background

High hepatitis C virus (HCV) rates have been reported in young people who inject drugs (PWID). We evaluated the clinical benefit and cost-effectiveness of testing among youth seen in communities with a high overall number of reported HCV cases.

Methods

We developed a decision analytic model to project quality-adjusted life years (QALYs), costs (2016 US$), and incremental cost-effectiveness ratios (ICERs) of 9 strategies for 1-time testing among 15- to 30-year-olds seen at urban community health centers. Strategies differed in 3 ways: targeted vs routine testing, rapid finger stick vs standard venipuncture, and ordered by physician vs by counselor/tester using standing orders. We performed deterministic and probabilistic sensitivity analyses (PSA) to evaluate uncertainty.

Results

Compared to targeted risk-based testing (current standard of care), routine testing increased the lifetime medical cost by $80 and discounted QALYs by 0.0013 per person. Across all strategies, rapid testing provided higher QALYs at a lower cost per QALY gained and was always preferred. Counselor-initiated routine rapid testing was associated with an ICER of $71000/QALY gained. Results were sensitive to offer and result receipt rates. Counselor-initiated routine rapid testing was cost-effective (ICER <$100000/QALY) unless the prevalence of PWID was <0.59%, HCV prevalence among PWID was <16%, reinfection rate was >26 cases per 100 person-years, or reflex confirmatory testing followed all reactive venipuncture diagnostics. In PSA, routine rapid testing was the optimal strategy in 90% of simulations.

Conclusions

Routine rapid HCV testing among 15- to 30-year-olds may be cost-effective when the prevalence of PWID is >0.59%.

Hepatitis C infection in patients with hereditary bleeding disorders: epidemiology, natural history, and management

Hereditary bleeding disorders include a group of diseases with abnormalities of coagulation. Prior to 1990, infection with hepatitis C virus (HCV) was mainly transmitted via pooled plasma products as a treatment for hereditary bleeding disorders. Anti-HCV positivity in these patients may be as high as >70% in some areas, while some of them have also been coinfected with human immunodeficiency virus. Since about 20% of HCV-infected patients clear the infection naturally, chronic HCV infection represents a significant health problem in this group of patients. Mortality due to chronic HCV infection is estimated to be >10 times higher in patients with hemophilia than in the general population, and is mainly due to liver cirrhosis and hepatocellular carcinoma. The antiviral treatment of HCV in patients with hereditary bleeding disorders is not different from that of any other infected patients. Nevertheless, many patients with hereditary bleeding disorders have declined (Peg)interferon-based treatment because of side effects. In recent years, multiple orally administrated direct-acting antivirals (DAAs) have been approved for HCV treatment. Unfortunately, there is not much experience from treating these patients with DAA regimens, as major studies and real-life data did not include adequate numbers of patients with inherited hemorrhagic disorders. However, the available data indicate that DAAs have an excellent safety profile with a sustained virological response rate of >90%.

HLA-B, HLA-C and KIR improve the predictive value of IFNL3 for Hepatitis C spontaneous clearance

IFNL3 is the strongest predictor of spontaneous resolution (SR) of hepatitis C virus (HCV), however, consideration of IFNL3 genotype alone is of limited clinical value for the prediction of SR or chronic HCV infection. The objective of this study was to analyze the impact of HLA-B, HLA-C and KIRs on SR, as well as their additive effects on the predictive value of the IFNL3 genotype. We conducted a retrospective study of HIV patients that included both SR and chronic HCV patients. In our study, 61.6% of patients with IFNL3 CC achieved SR, and 81.5% with non-CC genotypes did not achieve SR. HLA-B*44, HLA-C*12, and KIR3DS1 were identified as predictive factors for SR, with percentages of 77.4%, 85.7% and 86.2%, respectively, for patients who did not experience SR. The presence of at least one of these three markers, defined as a genetically unfavorable profile (GUP), combined with the IFNL3 non-CC genotype showed a value of 100% for non-SR. The absence of the three markers, defined as a genetically favorable profile (GFP), in addition to the IFNL3 CC genotype showed a percentage of 74.1% for SR. The combination of these markers in addition to the IFNL3 genotype improves the predictive value of IFNL3 for SR of acute HCV infection in HIV patients, which would be clinically valuable.

A Biomolecular Network Driven Proteinic Interaction in HCV Clearance

Hepatitis C virus infection causes chronic liver disease that leads to cancer-related mortality. Presently around 30% of the HCV (infected) affected population get rid of the infection through spontaneous disease clearance. This phenomenon is conducted by a set of reported immune candidate genes. Hence, this study focuses only on these immune-response related genes with aid of network approach, where the idea is to disseminate the network for better understanding of key functional genes and their transcription control activity. Based on the network analysis the IFNG, TNF, IFNB1, STAT1, NFKB1, STAT3, SOCS1, and MYD88 genes are prioritized as hub genes along with their common transcription factors (TFs), IRF9, NFKB1, and STAT1. The dinucleotide frequency of TF binding elements indicated GG-rich motifs in these regulatory elements. On the other hand, gene enrichment report suggests the regulation of response to interferon gamma signaling pathway, which plays central role in the spontaneous HCV clearance. Therefore, our study tends to prioritize the genes, TFs, and their regulatory pathway towards HCV clearance. Even so, the resultant hub genes and their TFs and TF binding elements could be crucial in underscoring the clearance activity in specific populations.

Scaling-up HCV prevention and treatment interventions in rural United States-model projections for tackling an increasing epidemic

BACKGROUND AND AIMS

Effective strategies are needed to address dramatic increases in hepatitis C virus (HCV) infection among people who inject drugs (PWID) in rural settings of the United States. We determined the required scale-up of HCV treatment with or without scale-up of HCV prevention interventions to achieve a 90% reduction in HCV chronic prevalence or incidence by 2025 and 2030 in a rural US setting.

DESIGN

An ordinary differential equation model of HCV transmission calibrated to HCV epidemiological data obtained primarily from an HIV outbreak investigation in Indiana.

SETTING

Scott County, Indiana (population 24 181), USA, a rural setting with negligible baseline interventions, increasing HCV epidemic since 2010, and 55.3% chronic HCV prevalence among PWID in 2015.

PARTICIPANTS

PWID.

MEASUREMENTS

Required annual HCV treatments per 1000 PWID (and initial annual percentage of infections treated) to achieve a 90% reduction in HCV chronic prevalence or incidence by 2025/30, either with or without scaling-up syringe service programmes (SSPs) and medication-assisted treatment (MAT) to 50% coverage. Sensitivity analyses considered whether this impact could be achieved without re-treatment of re-infections, and whether greater intervention scale-up was required due to the increasing epidemic in this setting.

FINDINGS

To achieve a 90% reduction in incidence and prevalence by 2030, without MAT and SSP scale-up, 159 per 1000 PWID (initially 24.9% of infected PWID) need to be HCV-treated annually. However, with MAT and SSP scaled-up, treatment rates are halved (89 per 1000 annually or 14.5%). To reach the same target by 2025 with MAT and SSP scaled-up, 121 per 1000 PWID (19.9%) need treatment annually. These treatment requirements are threefold higher than if the epidemic was stable, and the impact targets are unattainable without retreatment.

CONCLUSIONS

Combined scale-up of hepatitis C virus treatment and prevention interventions is needed to decrease the increasing burden of hepatitis C virus incidence and prevalence in rural Indiana, USA, by 90% by 2025/30.

Association of interferon lambda polymorphisms with elevated baseline viral loads in chronic hepatitis C virus genotype 6 infection

Globally, hepatitis C virus (HCV) is one of the major causes of hepatocellular carcinoma and liver cirrhosis. For clinical decision making, genetic variation in the interferon-λ (IFNL) cluster has been utilised as a baseline predictor of natural and interferon-based treatment-induced viral clearance. In Vietnam, where HCV genotypes 1 (g1) and g6 predominate, no prior studies have been conducted investigating associations of IFNL3/4 polymorphisms with spontaneous clearance (SC) or HCV viral load (VL) in chronic infection. In this study, we have investigated the host genetic variations in IFNL loci to determine the association of IFNL3/4 polymorphisms with HCV SC and baseline VLs in a Vietnamese HCV-seropositive cohort. The majority of the cohort harboured major homozygous polymorphisms in IFNL3/4 cluster (i.e. rs12979860-CC: 82.7%; rs8099917-TT: 84.8% and rs368234815-TT/TT: 85.5%) and the SC rates in these groups were 15.8%, 16.3% and 15.7%, respectively. In the minor allele groups, the resolution rates were lower (12% in rs12979860 non-CC, 9.1% in rs8099917 non-TT and 9.5% in rs368234815 non-TT/TT). Furthermore, in individuals harbouring minor alleles, females achieved higher SC rates than males. HCV g6-infected rs12979860 major homozygous individuals had significantly higher viral loads than individuals with minor alleles (CC: 6.56 log IU/ml vs. non-CC: 5.66 log IU/ml; P = 0.021). The association between IFNL3/4 genotypes with elevated HCV VL observed in HCV g6-infected individuals may have implications for the progression of liver disease in Southeast Asian countries where this viral genotype predominates and therefore warrants further studies.

Virus like particles as a platform for cancer vaccine development

Cancers have killed millions of people in human history and are still posing a serious health problem worldwide. Therefore, there is an urgent need for developing preventive and therapeutic cancer vaccines. Among various cancer vaccine development platforms, virus-like particles (VLPs) offer several advantages. VLPs are multimeric nanostructures with morphology resembling that of native viruses and are mainly composed of surface structural proteins of viruses but are devoid of viral genetic materials rendering them neither infective nor replicative. In addition, they can be engineered to display multiple, highly ordered heterologous epitopes or peptides in order to optimize the antigenicity and immunogenicity of the displayed entities. Like native viruses, specific epitopes displayed on VLPs can be taken up, processed, and presented by antigen-presenting cells to elicit potent specific humoral and cell-mediated immune responses. Several studies also indicated that VLPs could overcome the immunosuppressive state of the tumor microenvironment and break self-tolerance to elicit strong cytotoxic lymphocyte activity, which is crucial for both virus clearance and destruction of cancerous cells. Collectively, these unique characteristics of VLPs make them optimal cancer vaccine candidates. This review discusses current progress in the development of VLP-based cancer vaccines and some potential drawbacks of VLPs in cancer vaccine development. Extracellular vesicles with close resembling to viral particles are also discussed and compared with VLPs as a platform in cancer vaccine developments.

NK cells in self-limited HCV infection exhibit a more extensively differentiated, but not memory-like, repertoire

Natural killer (NK) cells have long been thought of as a purely innate immune cell population, but increasing reports have described developmental and functional qualities of NK cells that are commonly associated with cells of the adaptive immune system. Of these features, the ability of NK cells to acquire functional qualities associated with immunological memory and continuous differentiation resulting in the formation of specific NK cell repertoires has recently been highlighted in viral infection settings. By making use of a unique cohort of monitored, at-risk intravenous drug users in this study, we were able to dissect the phenotypic and functional parameters associated with NK cell differentiation and NK cell memory in patients 3 years after acute HCV infection and either the subsequent self-clearance or progression to chronicity. We observed increased expression of cytolytic mediators and markers CD56^bright and NKp46⁺ of NK cells in patients with chronic, but not self-limited HCV infection. Patients with a self-limited infection expressed higher levels of differentiation-associated markers CD57 and KIRs, and lower levels of NKG2A. A more extensively differentiated NK cell phenotype is associated with self-clearance in HCV patients, while the NK cells of chronic patients exhibited more naïve and effector NK cell phenotypic and functional characteristics. The identification of these distinct NK cell repertoires may shed light on the role NK cells play in determining the outcome of acute HCV infections, and the underlying immunological defects that lead to chronicity.

Hepatitis C disease transmission and treatment uptake: impact on the cost-effectiveness of new direct-acting antiviral therapies

BACKGROUND

Hepatitis C virus (HCV) treatment can reduce the incidence of future infections through removing opportunities for onward transmission. This benefit is not captured in conventional cost-effectiveness evaluations of treatment and is particularly relevant in patient groups with a high risk of transmission, such as those people who inject drugs (PWID), where the treatment rates have been historically low. This study aimed to quantify how reduced HCV transmission changes the cost-effectiveness of new direct-acting antiviral (DAA) regimens as a function of treatment uptake rates.

METHODS

An established model of HCV disease transmission and progression was used to quantify the impact of treatment uptake (10-100%), within the PWID population, on the cost-effectiveness of a DAA regimen versus pre-DAA standard of care, conducted using daclatasvir plus sofosbuvir in the UK setting as an illustrative example.

RESULTS

The consequences of reduced disease transmission due to treatment were associated with additional net monetary benefit of £24,304-£90,559 per patient treated at £20,000/QALY, when 10-100% of eligible patients receive treatment with 100% efficacy. Dependent on patient genotype, the cost-effectiveness of HCV treatment using daclatasvir plus sofosbuvir improved by 36-79% versus conventional analysis, at 10-100% treatment uptake in the PWID population.

CONCLUSIONS

The estimated cost-effectiveness of HCV treatment was shown to improve as more patients are treated, suggesting that the value of DAA regimens to the NHS could be enhanced by improved treatment uptake rates among PWID. However, the challenge for the future will lie in achieving increased rates of treatment uptake, particularly in the PWID population.

Utilization of Organs From Donors According to Hepatitis C Antibody and Nucleic Acid Testing Status: Time for Change

Previous studies have grouped all donors positive for hepatitis C virus (HCV) antibody (Ab). Only recently has donor HCV nucleic acid testing (NAT) become routine, and the impact of Ab and NAT status on organ utilization is unknown. Using the United Network for Organ Sharing database, we identified 9290 donors from 2015 to 2016 for whom both HCV Ab and NAT data were available and compared organ utilization by HCV status. Overall, 93.8% of donors were Ab negative and NAT negative (Ab-NAT-), 0.15% were Ab negative and NAT positive, 1.8% were Ab positive and NAT negative (Ab+NAT-), and 4.2% were both Ab and NAT positive (Ab+NAT+). Ab-NAT- donors donated at the highest rate for all organs except livers, of which Ab+NAT- donors donated at a higher rate (81.2% vs 73.2%, p = 0.03). Livers were discarded for reasons related to abnormal biopsies in Ab+NAT+ donors, whereas kidneys from Ab- or NAT-positive donors were discarded for reasons related to HCV status. Using a propensity score-matched model, we estimated that using Ab+NAT- donors at the same rate as Ab-NAT- donors could result in 48 more kidney donors, 37 more heart donors, and 15 more lung donors annually. We urge the use of HCV Ab+NAT- donors for appropriately selected and consenting recipients.

Hepatitis C virus viremic rate in the Middle East and North Africa: Systematic synthesis, meta-analyses, and meta-regressions

OBJECTIVES

To estimate hepatitis C virus (HCV) viremic rate, defined as the proportion of HCV chronically infected individuals out of all ever infected individuals, in the Middle East and North Africa (MENA).

METHODS

Sources of data were systematically-gathered and standardized databases of the MENA HCV Epidemiology Synthesis Project. Meta-analyses were conducted using DerSimonian-Laird random-effects models to determine pooled HCV viremic rate by risk population or subpopulation, country/subregion, sex, and study sampling method. Random-effects meta-regressions were conducted to identify predictors of higher viremic rate.

RESULTS

Analyses were conducted on 178 measures for HCV viremic rate among 19,593 HCV antibody positive individuals. In the MENA region, the overall pooled mean viremic rate was 67.6% (95% CI: 64.9-70.3%). Across risk populations, the pooled mean rate ranged between 57.4% (95% CI: 49.4-65.2%) in people who inject drugs, and 75.5% (95% CI: 61.0-87.6%) in populations with liver-related conditions. Across countries/subregions, the pooled mean rate ranged between 62.1% (95% CI: 50.0-72.7%) and 70.4% (95% CI: 65.5-75.1%). Similar pooled estimates were further observed by risk subpopulation, sex, and sampling method. None of the hypothesized population-level predictors of higher viremic rate were statistically significant.

CONCLUSIONS

Two-thirds of HCV antibody positive individuals in MENA are chronically infected. Though there is extensive variation in study-specific measures of HCV viremic rate, pooled mean estimates are similar regardless of risk population or subpopulation, country/subregion, HCV antibody prevalence in the background population, or sex. HCV viremic rate is a useful indicator to track the progress in (and coverage of) HCV treatment programs towards the set target of HCV elimination by 2030.

Epidemiology, transmission, diagnosis, and outcome of Hepatitis C virus infection

Hepatitis C infection is one of the main causes of chronic liver disorders worldwide. Nearly three percent (3%) of the world population has an HCV infection. Prevalence of HCV infection was higher in some groups such as injected drug users (IDUs) and HIV positive populations. Acute hepatitis has proven asymptomatic in most cases, and delay of diagnosis might lead to late onset of hepatocellular carcinoma and cirrhosis. Some host characteristics such as age, gender, body mass index, and viral properties are associated with HCV outcome hepatitis. Although disease progression is typically slow, some risk factors such as alcohol abuse and coinfection of patients with HBV and HIV can worsen the disease. On the other hand, viral overload is one of the main causes of prediction of HCV infection outcome. Prevalence of HCV infection will increase if we do not consider means of transmission, virus behaviors, and immunologic responses. Rapid diagnostic tests can help us to create preventive strategies among undeveloped villages and prisoners. Screening and training of the high-risk population such as IV drug users, dialysis patients, and hemophiliacs must be one of main HCV preventive programs. The present review is intended to help health policymakers to design suitable preventive and management programs.

Is elimination of hepatitis C from the UK by 2030 a realistic goal?

INTRODUCTION

Highly effective, combination therapy for chronic hepatitis C virus (HCV) infection is now available. Current cure rates are close to 100% and applicable to all patients irrespective of race, age, severity of liver disease or viral genotype. Remarkably for persistent infection, current treatment is recommended for as little as 12 weeks; recent studies suggest even shorter courses. In contrast to interferon-based therapy, present regimens have few side effects and serious adverse events are rare. The success and safety of these regimens has stimulated interest in the possible eventual elimination of HCV. Barriers to elimination include cost of drugs and finding patients in the community less likely to interact with medical services who are a potential reservoir of infection.

SOURCES OF DATA

Pubmed.

AREAS OF AGREEMENT

Antiviral agents already available are highly effective.

AREAS OF CONTROVERSY

The cost of the newer antiviral agents is very high, restricting treatment numbers in the UK in 2015/16 and focusing therapy on those patients with significant fibrosis. Recently, patients with less severe disease have been offered therapy, but delivery may be slowed by high costs. Many believe that insufficient pressure has been brought to bear to reduce costs. Eventual elimination will depend first on reducing treatment costs for those known to have chronic HCV infection and then finding patients in the community with infection unaware of their illness or reluctant/unable to engage with medical services.

AREAS FOR DEVELOPING RESEARCH

Determining the most effective strategies to identify 'invisible' patients in the community with chronic HCV infection.

Assessing the impact and cost-effectiveness of needle and syringe provision and opioid substitution therapy on hepatitis C transmission among people who inject drugs in the UK: an analysis of pooled data sets and economic modelling

Background

There is limited evidence of the impact of needle and syringe programmes (NSPs) and opioid substitution therapy (OST) on hepatitis C virus (HCV) incidence among people who inject drugs (PWID), nor have there been any economic evaluations.

Objective(s)

To measure (1) the impact of NSP and OST, (2) changes in the extent of provision of both interventions, and (3) costs and cost-effectiveness of NSPs on HCV infection transmission.

Design

We conducted (1) a systematic review; (2) an analysis of existing data sets, including collating costs of NSPs; and (3) a dynamic deterministic model to estimate the impact of differing OST/NSP intervention coverage levels for reducing HCV infection prevalence, incidence and disease burden, and incremental cost-effectiveness ratios to measure the cost-effectiveness of current NSP provision versus no provision.

Setting

Cost-effectiveness analysis and impact modelling in three UK sites. The pooled analysis drew on data from the UK and Australia. The review was international.

Participants

PWID.

Interventions

NSP coverage (proportion of injections covered by clean needles) and OST.

Outcome

New cases of HCV infection.

Results

The review suggested that OST reduced the risk of HCV infection acquisition by 50% [rate ratio (RR) 0.50, 95% confidence interval (CI) 0.40 to 0.63]. Weaker evidence was found in areas of high (≥ 100%) NSP coverage (RR 0.77, 95% CI 0.38 to 1.54) internationally. There was moderate evidence for combined high coverage of NSPs and OST (RR 0.29, 95% CI 0.13 to 0.65). The pooled analysis showed that combined high coverage of NSPs and OST reduced the risk of HCV infection acquisition by 29–71% compared with those on minimal harm reduction (no OST, ≤ 100% NSP coverage). NSPs are likely to be cost-effective and are cost-saving in some settings. The impact modelling suggest that removing OST (current coverage 81%) and NSPs (coverage 54%) in one site would increase HCV infection incidence by 329% [95% credible interval (CrI) 110% to 953%] in 2031 and at least double (132% increase; 95% CrI 51% to 306%) the number of new infections over 15 years. Increasing NSP coverage to 80% has the largest impact in the site with the lowest current NSP coverage (35%), resulting in a 27% (95% CrI 7% to 43%) decrease in new infections and 41% (95% CrI 11% to 72%) decrease in incidence by 2031 compared with 2016. Addressing homelessness and reducing the harm associated with the injection of crack cocaine could avert approximately 60% of HCV infections over the next 15 years.

Limitations

Findings are limited by the misclassification of NSP coverage and the simplified intervention definition that fails to capture the integrated services that address other social and health needs as part of this.

Conclusions

There is moderate evidence of the effectiveness of OST and NSPs, especially in combination, on HCV infection acquisition risk. Policies to ensure that NSPs can be accessed alongside OST are needed. NSPs are cost-saving in some sites and cost-effective in others. NSPs and OST are likely to prevent considerable rates of HCV infection in the UK. Increasing NSP coverage will have most impact in settings with low coverage. Scaling up other interventions such as HCV infection treatment are needed to decrease epidemics to low levels in higher prevalence settings.

Future work

To understand the mechanisms through which NSPs and OST achieve their effect and the optimum contexts to support implementation.

Funding

The National Institute for Health Research Public Health Research programme.

Reaching hepatitis C virus elimination targets requires health system interventions to enhance the care cascade

BACKGROUND

Modelling suggests that achieving the World Health Organization's elimination targets for hepatitis C virus (HCV) is possible by scaling up use of direct-acting antiviral (DAA) therapy. However, poor linkage to health services and retention in care presents a major barrier, in particular among people who inject drugs (PWID). We identify and assess the cost-effectiveness of additional health system interventions required to achieve HCV elimination targets in Australia, a setting where all people living with HCV have access to DAA therapy.

METHODS

We used a dynamic HCV transmission and liver-disease progression mathematical model among current and former PWID, capturing testing, treatment and other features of the care cascade. Interventions tested were: availability of point-of-care RNA testing; increased testing of PWID; using biomarkers in place of liver stiffness measurement; and scaling up primary care treatment delivery.

RESULTS

The projected treatment uptake in Australia reduced the number of people living with HCV from approximately 230,000 in 2015 to approximately 24,000 by 2030 and reduced incidence by 45%. However, the majority (74%) of remaining infections were undiagnosed and among PWID. Scaling up primary care treatment delivery and using biomarkers in place of liver stiffness measurement only reduced incidence by a further 1% but saved AU$32 million by 2030, with no change to health outcomes. Additionally replacing HCV antibody testing with point-of-care RNA testing increased healthcare cost savings to AU$62 million, increased incidence reduction to 64% and gained 11,000 quality-adjusted life years, but critically, additional screening of PWID was required to achieve HCV elimination targets.

CONCLUSION

Even with unlimited and unrestricted access to HCV DAA treatment, interventions to improve the HCV cascade of care and target PWID will be required to achieve elimination targets.

Seroprevalence of HCV and HIV infection among clients of the nation's longest-standing statewide syringe exchange program: A cross-sectional study of Community Health Outreach Work to Prevent AIDS (CHOW)

BACKGROUND

The Community Health Outreach Work to Prevent AIDS (CHOW) Project is the first and longest-standing statewide integrated and funded needle and syringe exchange program (SEP) in the US. Initiated on O'ahu in 1990, CHOW expanded statewide in 1993. The purpose of this study is to estimate the prevalences of hepatitis C virus (HCV) and human immunodeficiency virus (HIV) infection, and to characterize risk behaviors associated with infection among clients of a long-standing SEP through the analysis of the 2012 CHOW evaluation data.

METHODS

A cross-sectional sample of 130 CHOW Project clients was selected from January 1, 2012 through December 31, 2012. Questionnaires captured self-reported exposure information. HIV and HCV antibodies were detected via rapid, point-of-care FDA-approved tests. Log-binomial regressions were used to estimate prevalence proportion ratios (PPRs). A piecewise linear log-binomial regression model containing 1 spline knot was used to fit the age-HCV relationship.

RESULTS

The estimated seroprevalence of HCV was 67.7% (95% confidence interval [CI]=59.5-75.8%). HIV seroprevalence was 2.3% (95% CI=0-4.9%). Anti-HCV prevalence demonstrated age-specific patterns, ranging from 31.6% through 90.9% in people who inject drugs (PWID) <30 to ≥60 years respectively. Age (continuous/year) prior to spline knot at 51.5 years (adjusted PPR [APPR]=1.03; 95% CI=1.02-1.05) and months exchanging syringes (quartiles) (APPR=1.92; 95% CI=1.3-3.29) were independently associated with anti-HCV prevalence.

CONCLUSION

In Hawai'i, HCV prevalence among PWID is hyperendemic demonstrating age- and SEP duration-specific trends. Relatively low HIV prevalence compared with HCV prevalence reflects differences in transmissibility of these 2 blood-borne pathogens and suggests much greater efficacy of SEP for HIV prevention.