Patterns of hepatitis C virus RNA levels during acute infection: the InC3 study

Hepatitis C

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

Controlled Human Infection Model for Hepatitis C Virus Vaccine Development: Trial Design Considerations

The design of a clinical trial for a controlled human infection model (CHIM) to accelerate hepatitis C virus (HCV) vaccine development requires careful consideration. The design of a potential approach to HCV CHIM is outlined, involving initial sentinel cohorts to establish the safety and curability of the viral inoculum followed by larger cohorts to establish the spontaneous clearance rate for each inoculum. The primary endpoint would be HCV clearance by 24 weeks post-inoculation, recognizing that the prevention of chronic infection would be the primary goal of HCV vaccine candidates. Additional considerations are discussed, including the populations to be enrolled, the required monitoring approach, indications for antiviral therapy, and the required sample size for different CHIM approaches. Finally, safety considerations for CHIM participants are discussed.

Direct-Acting Antiviral Therapy for Treatment of Acute and Recent Hepatitis C Virus Infection: A Narrative Review

Following the discovery of hepatitis C virus (HCV) in 1989, 3 decades of basic, translational, and clinical research culminated in the development of direct-acting antiviral (DAA) therapy-curative oral treatment for HCV infection. The availability of DAA therapy revolutionized HCV clinical management, including acute (duration of infection <6 mo) and recent (duration of infection <12 mo) infection. Several DAA regimens, including the contemporary pan-genotypic combinations of sofosbuvir-velpatasvir and glecaprevir-pibrentasvir, have been shown to be safe and effective among people with acute and recent HCV infection, highlighting their potential in an HCV controlled human infection model. This article describes the natural history and management of acute and recent HCV infection in the era of DAA therapy and outlines a strategy for use of DAA therapies in the setting of an HCV controlled human infection model.

Optimal Frequency of Hepatitis C Virus (HCV) RNA Testing for Detection of Acute HCV Infection Among At-risk People With Human Immunodeficiency Virus: A Multicenter Study

Using 3-stage pooled-plasma hepatitis C virus (HCV) RNA testing performed quarterly among at-risk people with human immunodeficiency virus (PWH), we found that if testing had been performed every 6 or 12 months, 58.6%-91.7% of PWH who recently acquired HCV would be delayed for diagnosis and might contribute to onward HCV transmission with longer durations.

Mathematical modeling of plus-strand RNA virus replication to identify broad-spectrum antiviral treatment strategies

Plus-strand RNA viruses are the largest group of viruses. Many are human pathogens that inflict a socio-economic burden. Interestingly, plus-strand RNA viruses share remarkable similarities in their replication. A hallmark of plus-strand RNA viruses is the remodeling of intracellular membranes to establish replication organelles (so-called "replication factories"), which provide a protected environment for the replicase complex, consisting of the viral genome and proteins necessary for viral RNA synthesis. In the current study, we investigate pan-viral similarities and virus-specific differences in the life cycle of this highly relevant group of viruses. We first measured the kinetics of viral RNA, viral protein, and infectious virus particle production of hepatitis C virus (HCV), dengue virus (DENV), and coxsackievirus B3 (CVB3) in the immuno-compromised Huh7 cell line and thus without perturbations by an intrinsic immune response. Based on these measurements, we developed a detailed mathematical model of the replication of HCV, DENV, and CVB3 and show that only small virus-specific changes in the model were necessary to describe the in vitro dynamics of the different viruses. Our model correctly predicted virus-specific mechanisms such as host cell translation shut off and different kinetics of replication organelles. Further, our model suggests that the ability to suppress or shut down host cell mRNA translation may be a key factor for in vitro replication efficiency which may determine acute self-limited or chronic infection. We further analyzed potential broad-spectrum antiviral treatment options in silico and found that targeting viral RNA translation, especially polyprotein cleavage, and viral RNA synthesis may be the most promising drug targets for all plus-strand RNA viruses. Moreover, we found that targeting only the formation of replicase complexes did not stop the viral replication in vitro early in infection, while inhibiting intracellular trafficking processes may even lead to amplified viral growth.

Author summary

Plus-strand RNA viruses comprise a large group of related and medically relevant viruses. The current global pandemic of COVID-19 caused by the SARS-coronavirus-2 as well as the constant spread of diseases such as dengue and chikungunya fever show the necessity of a comprehensive and precise analysis of plus-strand RNA virus infections. Plus-strand RNA viruses share similarities in their life cycle. To understand their within-host replication strategies, we developed a mathematical model that studies pan-viral similarities and virus-specific differences of three plus-strand RNA viruses, namely hepatitis C, dengue, and coxsackievirus. By fitting our model to in vitro data, we found that only small virus-specific variations in the model were required to describe the dynamics of all three viruses. Furthermore, our model predicted that ribosomes involved in viral RNA translation seem to be a key player in plus-strand RNA replication efficiency, which may determine acute or chronic infection outcome. Furthermore, our in-silico drug treatment analysis suggests that targeting viral proteases involved in polyprotein cleavage, in combination with viral RNA replication, may represent promising drug targets with broad-spectrum antiviral activity.

Characterization of Acute HCV Infection and Transmission Networks in People Who Currently Inject Drugs in Catalonia: Usefulness of Dried Blood Spots

BACKGROUND AND AIMS

Accurate identification of recent HCV infections is critical for tracing the extent and mechanisms of ongoing transmission. We aimed to validate dried blood spot (DBS) samples for the assessment of Hepatitis C virus (HCV) genetic diversity and to determine epidemiological parameters including incidence, determinants of acute infection, and phylogenetic clustering in people who inject drugs (PWID).

APPROACH AND RESULTS

HCV nonstructural protein 5B next-generation sequencing was performed from plasma and/or DBS in 220 viremic PWID from the HepCdetect II study. No significant differences were found in consensus sequences or Shannon entropy (SE) intrahost diversity estimate between paired plasma/DBS specimens. SE values were used to identify acute infections with 93.3% sensitivity (95% CI, 0.81-1.06) and 95.0% specificity (95% CI, 0.88-1.02) in a set of well-defined controls. An acute HCV infection (either primary infection or reinfection) was detected in 13.5% of viremic participants and was associated with age ≤30 years (OR, 8.09), injecting less than daily (OR, 4.35), ≤5 years of injected drug use (OR, 3.43), sharing cocaine snorting straws (OR, 2.89), and being unaware of their HCV status (OR, 3.62). Annualized HCV incidence was estimated between 31 and 59/100 person-years. On phylogenetic analysis, 46.8% of viremic cases were part of a transmission pair or cluster; age ≤30 years (OR, 6.16), acute infection (OR, 5.73), and infection with subtype 1a (OR, 4.78) were independently associated with this condition.

CONCLUSIONS

The results obtained from plasma and DBS characterize PWID with acute infection and those involved in ongoing HCV transmission and allow estimating incidence from cross-sectional data. This information is critical for the design and assessment of targeted harm reduction programs and test-and-treat interventions and to facilitate monitoring of HCV elimination in this key population.

Interventions to reduce acute hepatitis C virus in HIV-positive MSM

PURPOSE OF REVIEW

The WHO has set ambitious targets for hepatitis C virus (HCV) elimination by 2030. In this review, we explore the possibility of HCV micro-elimination in HIV-positive (+) MSM, discussing strategies for reducing acute HCV incidence and the likely interventions required to meet these targets.

RECENT FINDINGS

With wider availability of directly acting antivirals (DAAs) in recent years, reductions in acute HCV incidence have been reported in some cohorts of HIV+ MSM. Recent evidence demonstrates that treatment in early infection is well tolerated, cost effective and may reduce the risk of onward transmission. Modelling studies suggest that to reduce incidence, a combination approach including behavioural interventions and access to early treatment, targeting both HIV+ and negative high-risk groups, will be required. HCV vaccine trials have not yet demonstrated efficacy in human studies, however phase one and two studies are ongoing.

SUMMARY

Some progress towards the WHO HCV elimination targets has been reported. Achieving sustained HCV elimination is likely to require a combination approach including early access to DAAs in acute infection and reinfection, validated and reproducible behavioural interventions and an efficacious HCV vaccine.

Randomized Trial of a Vaccine Regimen to Prevent Chronic HCV Infection

BACKGROUND

A safe and effective vaccine to prevent chronic hepatitis C virus (HCV) infection is a critical component of efforts to eliminate the disease.

METHODS

In this phase 1-2 randomized, double-blind, placebo-controlled trial, we evaluated a recombinant chimpanzee adenovirus 3 vector priming vaccination followed by a recombinant modified vaccinia Ankara boost; both vaccines encode HCV nonstructural proteins. Adults who were considered to be at risk for HCV infection on the basis of a history of recent injection drug use were randomly assigned (in a 1:1 ratio) to receive vaccine or placebo on days 0 and 56. Vaccine-related serious adverse events, severe local or systemic adverse events, and laboratory adverse events were the primary safety end points. The primary efficacy end point was chronic HCV infection, defined as persistent viremia for 6 months.

RESULTS

A total of 548 participants underwent randomization, with 274 assigned to each group. There was no significant difference in the incidence of chronic HCV infection between the groups. In the per-protocol population, chronic HCV infection developed in 14 participants in each group (hazard ratio [vaccine vs. placebo], 1.53; 95% confidence interval [CI], 0.66 to 3.55; vaccine efficacy, -53%; 95% CI, -255 to 34). In the modified intention-to-treat population, chronic HCV infection developed in 19 participants in the vaccine group and 17 in placebo group (hazard ratio, 1.66; 95% CI, 0.79 to 3.50; vaccine efficacy, -66%; 95% CI, -250 to 21). The geometric mean peak HCV RNA level after infection differed between the vaccine group and the placebo group (152.51×10³ IU per milliliter and 1804.93×10³ IU per milliliter, respectively). T-cell responses to HCV were detected in 78% of the participants in the vaccine group. The percentages of participants with serious adverse events were similar in the two groups.

CONCLUSIONS

In this trial, the HCV vaccine regimen did not cause serious adverse events, produced HCV-specific T-cell responses, and lowered the peak HCV RNA level, but it did not prevent chronic HCV infection. (Funded by the National Institute of Allergy and Infectious Diseases; ClinicalTrials.gov number, NCT01436357.).

T-Cell Immunity against the Hepatitis C Virus: A Persistent Research Priority in an Era of Highly Effective Therapy

Approximately 70% of acute hepatitis C virus (HCV) infections become chronic, indicating that the virus is exceptionally well adapted to persist in humans with otherwise normal immune function. Robust, lifelong replication of this small RNA virus does not require a generalized failure of immunity. HCV effectively subverts innate and adaptive host defenses while leaving immunity against other viruses intact. Here, the role of CD4⁺ and CD8⁺ T-cell responses in control of HCV infection and their failure to prevent virus persistence in most individuals are reviewed. Two issues of practical importance remain priorities in an era of highly effective antiviral therapy for chronic hepatitis C. First, the characteristics of successful T-cell responses that promote resolution of HCV infection are considered, as they will underpin development of vaccines that prevent HCV persistence. Second, defects in T-cell immunity that facilitate HCV persistence and whether they are reversed after antiviral cure to provide protection from reinfection are also addressed.

Evaluation of the Aptima HCV Quant Dx Assay for Hepatitis C Virus RNA Detection from Fingerstick Capillary Dried Blood Spot and Venepuncture-Collected Samples

BACKGROUND

Simplified diagnostic strategies are needed increase hepatitis C virus (HCV) testing to determine active infection and link people into treatment. Collection methods such as dried blood spots (DBS) have advantages over standard phlebotomy, especially within marginalized populations.

METHODS

We evaluated the diagnostic performance of the Aptima HCV Quant assay for the quantification and detection of HCV RNA from paired DBS and venepuncture samples. Specimens were collected from participants enrolled in an Australian observational study. We compared HCV RNA detection from DBS against venepuncture samples (gold standard).

RESULTS

One hundred sixty-four participants had paired samples and HCV RNA was detected in 45 (27% [95% confidence interval, 21%-35%]) by the Aptima assay in venepuncture samples. Sensitivity of the Aptima assay for HCV RNA quantification from DBS (≥10 IU/mL in plasma) was 100% and specificity was 100%. Sensitivity for HCV RNA detection from DBS was 95.6% and specificity was 94.1%. A small bias in plasma over DBS was observed with good agreement (R2 = 0.96).

CONCLUSIONS

The Aptima HCV Quant assay detects active infection from DBS samples with acceptable diagnostic performance and is clinically comparable to plasma. These data will strengthen the case for the registration of a DBS kit insert claim, enabling future clinical utility.

Envelope-Specific IgG3 and IgG1 Responses Are Associated with Clearance of Acute Hepatitis C Virus Infection

Hepatitis C virus (HCV) can be cleared naturally in a subset of individuals. However, the asymptomatic nature of acute HCV infection makes the study of the early immune response and defining the correlates of protection challenging. Despite this, there is now strong evidence implicating the humoral immune response, specifically neutralising antibodies, in determining the clearance or chronicity outcomes of primary HCV infection. In general, immunoglobulin G (IgG) plays the major role in viral neutralisation. However, there are limited investigations of anti-HCV envelope protein 2 (E2) isotypes (IgM, IgG, IgA) and IgG subclasses (IgG1-4) in early HCV infection. In this study, using a rare cohort of 14 very recently HCV-infected individuals (4-45 days) with varying disease outcome (n = 7 clearers), the timing and potency of anti-HCV E2 isotypes and IgG subclasses were examined longitudinally, in relation to neutralising antibody activity. Clearance was associated with anti-E2 IgG, specifically IgG1 and IgG3, and appeared essential to prevent the emergence of new HCV variants and the chronic infection outcome. Interestingly, these IgG responses were accompanied by IgM antibodies and were associated with neutralising antibody activity in the subjects who cleared infection. These findings provide novel insights into the early humoral immune response characteristics associated with HCV disease outcome.

HCV incidence is associated with injecting partner age and HCV serostatus mixing in young adults who inject drugs in San Francisco

BACKGROUND

HCV incidence is increasing in the US, notably among younger people who inject drugs (PWID). In a cohort of young adult (age<30 years) PWID in San Francisco we examined whether 'injecting partner mixing' factors, i.e. age of partner and knowledge of their HCV serostatus, were associated with HCV transmission.

METHODS

In 448 susceptible PWID studied prospectively. All participants were asked to report characteristics and behaviors they engaged in with up to 3 injecting partners defined as "people whom you injected the most with" in the past month". These partnerships did not specify that drugs or injecting equipment was shared. HCV incidence was estimated by age of up to 3 injecting partners, categorized as: (i) all <30; (ii) mixed-age (<&≥30); and (iii) all ≥30 years and perceived knowledge of the HCV status of participants' injecting partners' HCV status. Interaction was evaluated between partnership age categories and perceived HCV status of partners.

RESULTS

Between 2006-2018, overall HCV incidence (/100 person years observation [pyo]) was 19.4 (95% CI: 16.4, 22.9). Incidence was highest in those with mixed-age partnerships: 28.5 (95% CI: 21.8, 37.1) and those whose partners were all <30 (23.9; 95% CI: 18.8, 30.4), and lowest if partners were ≥30 (7.5; 95% CI: 4.8, 11.8). In a multivariable analyses adjusting for age, sex (of index), injection frequency, and injection partnership 'monogamy', we found evidence for an interaction: the highest HCV incidence was seen in PWID whose partners were all <30 and who knew at least one of their partners was HCV-positive (58.9, 95% CI: 43.3, 80.0; p<0.01).

CONCLUSIONS

Younger injectors are more likely to acquire HCV from their similarly-aged peers, than older injecting partners. Protective seroadaptive behavior may contribute to reduce incidence. These findings can inform new HCV prevention approaches for young PWID needed to curb the HCV epidemic.

Modeling of patient virus titers suggests that availability of a vaccine could reduce hepatitis C virus transmission among injecting drug users

The major route of hepatitis C virus (HCV) transmission in the United States is injection drug use. We hypothesized that if an HCV vaccine were available, vaccination could affect HCV transmission among people who inject drugs by reducing HCV titers after viral exposure without necessarily achieving sterilizing immunity. To investigate this possibility, we developed a mathematical model to determine transmission probabilities relative to the HCV RNA titers of needle/syringe-sharing donors. We simulated sharing of two types of syringes fitted with needles that retain either large or small amounts of fluid after expulsion. Using previously published viral kinetics data from both naïve subjects infected with HCV and reinfected individuals who had previously cleared an HCV infection, we estimated transmission risk between pairs of serodiscordant injecting drug users, accounting for syringe type, rinsing, and sharing frequency. We calculated that the risk of HCV transmission through syringe sharing increased ~10-fold as viral titers (log₁₀ IU/ml) increased ~25-fold. Cumulative analyses showed that, assuming sharing episodes every 7 days, the mean transmission risk over the first 6 months was >90% between two people sharing syringes when one had an HCV RNA titer >5 log₁₀ IU/ml. For those with preexisting immunity that rapidly controlled HCV, the cumulative risk decreased to 1 to 25% depending on HCV titer and syringe type. Our modeling approach demonstrates that, even with transient viral replication after exposure during injection drug use, HCV transmission among people sharing syringes could be reduced through vaccination if an HCV vaccine were available.

Role of HCV Viremia in Corroborated HCV Transmission Events Within Young Adult Injecting Partnerships

Background

Hepatitis C virus (HCV), a major cause of morbidity and mortality, is common and rising among young persons who inject drugs (PWID). Reducing the level of viremia may be an intervention, yet the impact of viremia on HCV transmission is unknown.

Methods

We conducted a prospective study of injecting partnerships (Partner Study) of young adult (age < 30 years) PWID within the UFO Study, which enrolled those at risk for HCV or with seronegative viremic infection and up to 3 HCV RNA-positive regular injecting partners. We examined the level of HCV viremia and stage of infection in the HCV-positive partner in regression analyses of HCV transmission events that were corroborated via HCV phylogenetic linkage analyses.

Results

We enrolled 69 at-risk/acutely infected PWID. There were 25 new HCV infections (incidence rate, 35.9 per 100 person-years; 95% confidence interval [CI], 24.3-53.2 per 100 person-years); 12/25 (48%) were phylogenetically linked to at least 1 partner. We found no association between the infected partner's quantitative level of HCV viremia and likely transmission in multivariate analyses (adjusted odds ratio [AOR], 0.90; 95% confidence interval [CI], 0.55-1.46); however, seronegative viremic infection in the infected partner was associated with increased transmission (AOR, 28.02; 95% CI, 5.61-139.95).

Conclusions

The HCV viremia level was not associated with increased odds of transmission, yet acute HCV infection (seronegative viremic) was. Explanations include high-risk behavior during acute infection or missed fluctuations in viremia during acute infection. Both point to the need for frequent testing to detect new infection and attempt to prevent onward transmission.

Genomic variability of within-host hepatitis C variants in acute infection

Interactions between the host immune system and the viral variants determine persistence of hepatitis C virus (HCV) infection after the acute phase of infection. This study describes the genetic variability of within-host HCV viral variants in acute infection and correlates it with host- and virus-related traits and infection outcome. Next generation sequence data (Illumina, MiSeq platform) of viral genomes from 116 incident acute infections (within 180 days of infection) were analysed to determine all the single nucleotide polymorphism (SNP) frequencies above a threshold of 0.1%. The variability of the SNPs for the full open reading frame of the genome as well as for each protein coding region were compared using mean standardized Shannon entropy (SE) values calculated separately for synonymous and nonsynonymous mutations. The envelope glycoproteins regions (E1 and E2) had the highest SE values (indicating greater variability) followed by the NS5B region. Nonsynonymous mutations rather than synonymous mutations were the main contributors to genomic variability in acute infection. The mean difference of Shannon entropy was also compared between subjects after categorizing the samples according to host and virus-related traits. Host IFNL3 allele CC polymorphism at rs12979860 (vs others) and viral genotype 1a (vs 3a) were associated with higher genomic variability across the viral open reading frame. Time since infection, host gender or continent of origin was not associated with the viral genomic variability. Viral genomic variability did not predict spontaneous clearance.

Evaluation of the Aptima HCV Quant Dx Assay Using Serum and Dried Blood Spots

Hepatitis C virus (HCV) RNA quantitation is the primary method by which active HCV infections are identified and the response to direct-acting antiviral therapy is monitored. This study describes the evaluation of the Aptima HCV Quant Dx assay (Aptima HCV) performed on the Panther system. The clinical performance of Aptima HCV was compared to that of the Cobas AmpliPrep/Cobas TaqMan HCV test v2.0 (CAP/CTM). Overall agreement was 84.9% (186/219) with a kappa statistic of 0.755 (standard error, 0.037; 95% confidence interval [CI], 0.682 to 0.828). Passing-Bablok regression of log₁₀ IU/ml values revealed a regression line of Y = 1.163 × X - 0.991 (95% CI of the slope, 1.103 to 1.221, and intercept, -1.341 to -0.642). The 95% lower limit of detection (LLOD) for Aptima HCV on dried blood spot (DBS) samples was calculated to be 2.43 log₁₀ IU/ml (267 IU/ml; 95% CI, 2.31 to 2.73 log₁₀ IU/ml [204 to 540 IU/ml]). A comparison of Aptima HCV testing on paired DBS and serum specimens collected from patients at the time of routine blood collection for CAP/CTM demonstrated an overall agreement of 90.1% (82/91) with a kappa statistic of 0.657 (standard error, 0.101; 95% CI, 0.458 to 0.855). In conclusion, Aptima HCV provides a suitable alternative for HCV RNA testing on serum and DBS samples.

Genomic characterization of hepatitis C virus transmitted founder variants with deep sequencing

Transfer of hepatitis C virus (HCV) infection from a donor to a new recipient is associated with a bottleneck of genetic diversity in the transmitted viral variants. Existing data suggests that one, or very few, variants emerge from this bottleneck to establish the infection (transmitted founder [T/F] variants). In HCV, very few T/F variants have been characterized due to the challenges of obtaining early infection samples and of high throughput viral genome sequencing. This study used a large, acute HCV, deep-sequenced dataset from first viremia samples collected in nine prospective cohorts across four countries, to estimate the prevalence of single T/F viruses, and to identify host and virus-related factors associated with infections initiated by a single T/F variant. The short reads generated by Illumina sequencing were used to reconstruct viral haplotypes with two haplotype reconstruction algorithms. The haplotypes were examined for random mutations (Poisson distribution) and a star-like phylogeny to identify T/F viruses. The findings were cross-validated by haplotype reconstructions across three regions of the genome (Core-E2, NS3, NS5A) to minimize the possibility of spurious overestimation of single T/F variants. Of 190 acute infection samples examined, 54 were very early acute infections (HCV antibody negative, RNA positive), and single transmitted founders were identified in 14 (26%, 95% CI: 16-39%) after cross validation across multiple regions of the genome with two haplotype reconstruction algorithms. The presence of a single T/F virus was not associated with any host or virus-related factors, notably viral genotype or spontaneous clearance. In conclusion, approximately one in four new HCV infections originates from a single T/F virus. Resolution of genomic sequences of single T/F variants is the first step in exploring unique properties of these variants in the infection of host hepatocytes.

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.

Community-based screening of hepatitis C with a one-step RNA detection algorithm from dried-blood spots: Analysis of key populations in Barcelona, Spain

Alternative strategies are required to enhance the diagnosis of silent hepatitis C virus (HCV) infections in key populations at risk. Among them, HCV prevalence and bio-behavioural data are scarce for HIV-negative men who have sex with men (MSM) and men and trans-women sex workers. We sought to describe and assess the potential benefits of a community-based one-step HCV screening and confirmatory strategy for these populations in Barcelona. The screening strategy based on a real-time RT-PCR assay for HCV-RNA detection in dried-blood spots (DBS) was validated and implemented in addition to an antibody point-of-care test in a community centre. HCV prevalence was assessed, and bio-behavioural data were collected. The molecular assay was precise, reproducible, sensitive and specific. Four HIV-negative MSM reported being currently infected (0.75% HCV self-reported prevalence). Implementation of DBS testing was easy, and acceptability was >95%, but no silent HCV case was diagnosed (N = 580). High-risk sexual practices and drug use for sex were reported frequently. HIV prevalence was 4.7% in MSM and 10% in sex workers. Self-reported prevalence of other STIs ranged from 11.3% to 36.2%. In conclusion, HCV-RNA testing in DBS showed a good performance, but the assessed one-step strategy does not seem beneficial in this setting. Although no silent HCV infections were detected, the observed high-risk behaviours and prevalence of other STIs suggest that HCV spread should be periodically monitored among these populations in Barcelona by means of behavioural surveillance, rapid antibody testing and molecular confirmation in DBS.

Interleukin gene polymorphisms and susceptibility to HIV-1 infection: a meta-analysis

Some subjects are repeatedly exposed to human immunodeficiency virus (HIV), yet they remain uninfected. This suggests the existence of host-resistance mechanisms. The current study synthesizes the evidence regarding the association between interleukin (IL) gene polymorphisms and HIV susceptibility. Medline, Scopus and the Web of Science databases were systematically searched, and a meta-analysis of case-control studies was conducted. Univariate and bivariate methods were used. The literature search identified 42 eligible studies involving 15,727 subjects. Evidence was obtained on eight single-nucleotide polymorphisms (SNPs): IL1A -889 C>T (rs1800587), IL1B +3953/4 C>T (rs1143634), IL4 -589/90 C>T (rs2243250), IL6 -174 G>C (rs1800795), IL10 -592 C>A (rs1800872), IL10-1082 A>G (rs1800896), IL12B -1188 A>C (rs3212227) and IL28B C>T (rs12979860). The IL1B +3953/4 C>T variant appears to increase the risk of HIV acquisition, under the assumption of a recessive genetic model (odds ratio (OR): 4.47, 95% CI: 2.35-8.52). The AA homozygotes of the IL10 -592 C>A SNP had an increased, marginally nonsignificant, risk (OR: 1.39, 95% CI: 0.97-2.01). It reached, however, significance in sub analyses (OR: 1.49, 95% CI: 1.04-2.12). Finally, the well-studied hepatitis C virus (HCV) infection IL28B (rs12979860) CT/TT genotypes were associated with a 27% decrease in HIV infection risk, especially in populations infected with HCV (OR: 0.73, 95% CI: 0.57-0.95). Interleukin signalling is perhaps important in HIV infection and some interleukin genetic variants may affect the risk of HIV acquisition. Approaches targeting specific genes and genome wide association studies should be conducted to decipher the effect of these polymorphisms.

HCV avidity as a tool for detection of recent HCV infection: Sensitivity depends on HCV genotype

Accurate detection of incident hepatitis C virus (HCV) infection is required to target and evaluate public health interventions, but acute infection is largely asymptomatic and difficult to detect using traditional methods. Our aim was to evaluate a previously developed HCV avidity assay to distinguish acute from chronic HCV infection. Plasma samples collected from recent seroconversion subjects in two large Australian cohorts were tested using the avidity assay, and the avidity index (AI) was calculated. Demographic and clinical characteristics of patients with low/high AI were compared via logistic regression. Sensitivity and specificity of the assay for recent infection and the mean duration of recent infection (MDRI) were estimated stratified by HCV genotype. Avidity was assessed in 567 samples (from 215 participants), including 304 with viraemia (defined as ≥250 IU/mL). An inverse relationship between AI and infection duration was found in viraemic samples only. The adjusted odds of a low AI (<30%) decreased with infection duration (odds ratio [OR] per week of 0.93; 95% CI:0.89-0.97), and were lower for G1 compared with G3 samples (OR = 0.14; 95% CI:0.05-0.39). Defining recent infection as <26 weeks, sensitivity (at AI cut-off of 20%) was estimated at 48% (95% CI:39-56%), 36% (95% CI:20-52%), and 65% (95% CI:54-75%) and MDRI was 116, 83, and 152 days for all genotypes, G1, and G3, respectively. Specificity (≥52 weeks infection duration, all genotypes) was 96% (95% CI:90-98%). HCV avidity testing has utility for detecting recent HCV infection in patients, and for assessing progress in reaching incidence targets for eliminating transmission, but variation in assay performance across genotype should be recognized.

Estimating the Time to Diagnosis and the Chance of Spontaneous Clearance During Acute Hepatitis C in Human Immunodeficiency Virus-Infected Individuals

BACKGROUND

Hepatitis C virus (HCV) infection is often asymptomatic, and the date of infection is almost impossible to determine. Furthermore, spontaneous clearance (SC) may occur, but little is known about its time of occurrence.

METHODS

Data on human immunodeficiency virus (HIV)-HCV coinfected individuals were used to inform a stochastic simulation model of HCV viral load kinetics, alanine aminotransferase (ALT), and HCV antibodies during acute hepatitis C. The dates of diagnosis and potential SC were estimated through a Bayesian approach. Hepatitis C virus diagnosis was assumed to be based on an elevated ALT level detected during a control visit for HIV-infected individuals, which occurred every 3 months (scenario A) or every 6 months (scenario B).

RESULTS

We found that HCV diagnosis occurred after a median of 115 days and 170 days of infection in scenarios A and B, respectively. Among spontaneous clearers, SC occurred after a median time of 184 days after infection. Seven percent (scenario B) to 10% (scenario A) of SCs appeared more than 6 months after diagnosis, and 3% (both scenarios) of SCs appeared more than 1 year after diagnosis.

CONCLUSIONS

Acute hepatitis C diagnosis occurs late in HIV-HCV coinfected individuals. Screening for HCV in HIV-infected individuals should be performed frequently to reduce delays. Our findings about late occurrence of SC support "wait and see" strategies for treatment initiation from an individual basis. However, early treatment initiation may reduce HCV transmission.

Phylogenetic analysis of full-length, early infection, hepatitis C virus genomes among people with intravenous drug use: the InC3 Study

Cross-continental phylogenetic analysis is important to understand subtle molecular differences of currently circulating hepatitis C virus (HCV) subtypes. Existence of such differences can be crucial in pursuing a universal hepatitis C vaccine. We characterized molecular epidemiology of early HCV infections identified across nine cohorts [North America (n=4), Australia (n=4) and Europe (n=1)] in the International Collaborative of Incident HIV and Hepatitis C in Injecting Cohorts (InC³ ). One hundred and ninety-two full-length HCV genomes were amplified from plasma of incident infections and subjected to next generation sequencing to establish the largest cross-continental, full-length acute HCV genomic data set available to date. Genomes from the most common subtypes (1a: n=94, 2b: n=15 and 3a: n=68) were used in phylogenetic analysis. Using full genome trees, 78 sequences (44%) were found to lie within 29 phylogenetic clusters/pairs defined on the basis of molecular similarity of consensus sequences. Of these, 26 each had exclusively Australian or North American sequences indicating a strong geographical bias for molecular similarity. On further analysis of behavioural and demographic associations, binary logistic regression analysis showed that older age and non-Caucasian ethnicity were significantly associated with clustering. HCV probably evolves in micro-epidemics within geographically isolated communities.

Analysis of resistance-associated substitutions in acute hepatitis C virus infection by deep sequencing across six genotypes and three continents

Several direct-acting antivirals (DAAs) have been approved for the treatment of chronic hepatitis C virus (HCV) infections, opening the door to highly effective interferon-free treatment regimens. Resistance-associated substitutions (RASs) have been reported both in treatment-naïve patients and following treatment with protease (NS3), phosphoprotein (NS5A) and polymerase (NS5B) inhibitors. The prevalence of naturally occurring RASs in untreated HCV-infected individuals has mostly been analysed in those infected with genotype 1 (GT1), in the late phase of infection, and only within limited regions of the genome. Furthermore, the geographic distribution of RASs remains poorly characterized. In this study, we used next-generation sequencing to analyse full-length HCV genomes for the prevalence of RASs in acute HCV infections identified in nine international prospective cohorts. RASs were analysed in 179 participants infected with all six major HCV genotypes (GT1-GT6), and the geographic distribution of RASs was assessed in 107 GT1a and GT3a samples. While RASs were detected at varied frequencies across the three genomic regions, and between genotypes, RASs relevant to multiple DAAs in the leading IFN-free regimens were rarely detected in combination. Low-frequency RASs (<10% of the viral population) were also shown to have a GT-specific distribution. The main RASs with geographic associations were NS3 Q80K in GT1a samples and NS5B N142T in GT3a. These data provide the backdrop for prospective surveillance of RASs during DAA treatment scale-up.

Clinical epidemiology of acute hepatitis C in South America

There is scarce data pertaining to acute hepatitis C (aHC) infection in South America. We aimed to describe clinical characteristics and evolution of aHC in a South American cohort. A retrospective survey was conducted at 13 hepatology units. All patients ≥16 years old with aHC diagnosis were included. Demographic, clinical and outcome information were registered in a standardized ad hoc questionnaire. Sixty-four patients were included. The majority were middle-aged (median age: 46 years) and female (65.6%); most of them were symptomatic at diagnosis (79.6%). HCV-1 was the most prevalent genotype (69.2%). Five patients had liver failure: three cases of severe acute hepatitis, one case of fulminant hepatitis and one case of acute-on-chronic liver failure. Nosocomial exposure was the most prevalent risk factor. Evolution was assessed in 46 patients. In the untreated cohort, spontaneous resolution occurred in 45.8% and was associated with higher values of AST/ALT and with the absence of intermittent HCV RNA viremia (P = 0.01, 0.05, and 0.01, respectively). In the treated cohort, sustained virological response was associated with nosocomial transmission and early treatment initiation (P = 0.04 each). The prevalence of nosocomial transmission in this South-American cohort of aHC stresses the importance of following universal precautions to prevent HCV infection. J. Med. Virol. 89:276-283, 2017. © 2016 Wiley Periodicals, Inc.

Traceability, reproducibility and clinical evaluation of Sansure Realtime HCV RNA assay

Background

Accurate quantitative detection of hepatitis C virus (HCV) RNA is critical for diagnosis of acute or chronic HCV infection, and for follow-up of virologic response during HCV targeted therapy. In the present study, traceability and reproducibility of a novel China-certified domestic Sansure HCV RNA diagnostic assay (Sansure, Changsha, Hunan, China) was evaluated and the clinical performance of this assay was also analyzed.

Methods

Traceability of the Sansure HCV RNA assay to the WHO international standard for HCV (genotype 1a) was detected across multiple centers. Reproducibility, accuracy (the differences of observed average concentrations and expected concentrations) and precision were assessed using series dilutions of World HCV RNA performance panel WWHV303-02 (HCV-1b), WWHV303-04(HCV-2a), WWHV303-11(HCV-3a) and WWHV303-19 (HCV-6a). In addition, both Sansure HCV RNA and CAP/CTM HCV (Roche, Branchburg, NJ, USA) assays were used to detect HCV RNA in 346 EDTA anti-coagulated plasma samples from previous HCV-infected patients, during and after antiviral therapy.

Results

The Sansure assay showed good traceability by agreeing with the HCV-1a WHO standard across all five concentrations tested (25, 50, 100, 1000, 10000 IU/ml). The differences between observed average concentrations and expected concentrations were all within 0.2 log₁₀ IU/ml. HCV WWHV303 standards across 4 HCV genotypes (1b, 2a, 3a and 6a) were used for evaluation of reproducibility and the accuracy of the test were all within 0.2 log₁₀ IU/ml. The inter-assay variations across the above 4 HCV genotypes were all less than 0.03 on each evaluated concentration, indicating good precision of Sansure HCV RNA assay. In clinical practice, concordant results were determined in 99.42 % (344/346) samples (215 positive and 129 negative samples). Two specimens with negative HCV RNA results by Sansure assay were detected positive by CAP/CTM HCV test. Correlation analysis indicated a significantly positive correlation in detected HCV RNA concentrations (r = 0.9439, P < 0.0001). HCV RNA levels in 95.35 % (205/215) specimens were within mean difference ± 1.96 SD as tested by both assays.

Conclusions

With the advantages of traceability, reproducibility and lower price, Sansure HCV RNA assay represented an alternative option for HCV RNA detection in hospital and medical institution in China.

Immunopathogenesis of Hepatitis C Virus Infection

Despite advances in therapy, hepatitis C virus infection remains a major global health issue with 3 to 4 million incident cases and 170 million prevalent chronic infections. Complex, partially understood, host-virus interactions determine whether an acute infection with hepatitis C resolves, as occurs in approximately 30% of cases, or generates a persistent hepatic infection, as occurs in the remainder. Once chronic infection is established, the velocity of hepatocyte injury and resultant fibrosis is significantly modulated by immunologic as well as environmental factors. Immunomodulation has been the backbone of antiviral therapy despite poor understanding of its mechanism of action.

Hepatitis C virus infection and spontaneous clearance in HTLV-1 and HIV co-infected patients in Salvador, Bahia, Brazil

BACKGROUND

While 20-40% of patients with hepatitis C virus (HCV) monoinfection will spontaneously clear the virus, less is known regarding clearance with coinfections. HCV, human immunodeficiency virus (HIV), and human T-cell lymphotrophic virus 1 and 2 (HTLV-1/2) coinfection occurs due to shared routes of transmission and is prevalent in Brazil.

OBJECTIVES

To compare the proportion of patients who have spontaneously cleared HCV in patients with HCV monoinfection to patients coinfected by HCV/HIV, or HCV/HIV/HTLV-1.

METHODS

Using medical records from two clinics in Salvador, Brazil, including demographic data and serological markers of HCV, HIV and HTLV-I/II, cross-sectional data was obtained from 197 patients. Patients who were anti-HCV positive and HCV RNA negative, and who did not receive HCV treatment were defined as having cleared infection.

RESULTS

Nineteen patients (9.5%) showed evidence of spontaneous HCV clearance; with clearance in 9 of 108 (8.3%) patients in the HCV monoinfected group, 5 of 68 (7.4%) patients with HCV/HIV, and 5 of 21 (23.8%) patients with HCV/HIV/HTLV. Demographic data were not associated with HCV clearance status. Patients coinfected with both HIV and HTLV-1 had increased odds (5.50; 95% CI 1.00, 30.17) of spontaneous clearance of HCV compared with patients who were HIV negative or of unknown HIV status.

CONCLUSION

Our study found that patients coinfected with HIV and HTLV-1 were more likely to spontaneously clear hepatitis C virus than patients with HIV/HCV or HCV alone. The effects of HTLV coinfection on the immune response of such patients may be associated with these findings.

Enhancing the detection and management of acute hepatitis C virus infection

Acute HCV infection refers to the 6-month period following infection acquisition, although this definition is somewhat arbitrary. While spontaneous clearance occurs in approximately 25%, the majority will develop chronic HCV infection with the potential for development of cirrhosis, end stage liver disease and hepatocellular carcinoma. Detection of acute HCV infection has been hampered by its asymptomatic or non-specific presentation, lack of specific diagnostic tests and the inherent difficulties in identifying and following individuals at highest risk of transmitting and acquiring HCV infection, such as people who inject drugs (PWID). However, recognition of those with acute infection may have individual and population level benefits and could represent an ideal opportunity for intervention. Despite demonstration that HCV treatment is feasible and successful in PWID, treatment uptake remains low with multiple barriers to care at an individual and systems level. Given the burden of HCV-related disease among PWID, strategies to enhance HCV assessment, treatment and prevention in this group are urgently needed. As the therapeutic landscape of chronic HCV management is revolutionised by the advent of simple, highly effective directly-acting antiviral (DAA) therapy, similar opportunities may exist in acute infection. This review will discuss issues surrounding improving the detection and management of acute HCV infection, particularly in PWID.

Acute Hepatitis C Virus Infection Induces Consistent Changes in Circulating MicroRNAs That Are Associated with Nonlytic Hepatocyte Release

Plasma microRNAs (miRNAs) change in abundance in response to disease and have been associated with liver fibrosis severity in chronic hepatitis C virus (HCV) infection. However, the early dynamics of miRNA release during acute HCV infection are poorly understood. In addition, circulating miRNA signatures have been difficult to reproduce among separate populations. We studied plasma miRNA abundance during acute HCV infection to identify an miRNA signature of early infection. We measured 754 plasma miRNAs by quantitative PCR array in a discovery cohort of 22 individuals before and during acute HCV infection and after spontaneous resolution (n = 11) or persistence (n = 11) to identify a plasma miRNA signature. The discovery cohort derived from the Baltimore Before and After Acute Study of Hepatitis. During acute HCV infection, increases in miR-122 (P < 0.01) and miR-885-5p (Pcorrected < 0.05) and a decrease in miR-494 (Pcorrected < 0.05) were observed at the earliest time points after virus detection. Changes in miR-122 and miR-885-5p were sustained in persistent (P < 0.001) but not resolved HCV infection. The circulating miRNA signature of acute HCV infection was confirmed in a separate validation cohort that was derived from the San Francisco-based You Find Out (UFO) Study (n = 28). As further confirmation, cellular changes of signature miRNAs were examined in a tissue culture model of HCV in hepatoma cells: HCV infection induced extracellular release of miR-122 and miR-885-5p despite unperturbed intracellular levels. In contrast, miR-494 accumulated intracellularly (P < 0.05). Collectively, these data are inconsistent with necrolytic release of hepatocyte miRNAs into the plasma during acute HCV infection of humans.

IMPORTANCE

MicroRNAs are small noncoding RNA molecules that emerging research shows can transmit regulatory signals between cells in health and disease. HCV infects 2% of humans worldwide, and chronic HCV infection is a major cause of severe liver disease. We profiled plasma miRNAs in injection drug users before, during, and (in the people with resolution) after HCV infection. We discovered miRNA signatures of acute and persistent viremia and confirmed these findings two ways: (i) in a separate cohort of people with newly acquired HCV infection and (ii) in an HCV cell culture system. Our results demonstrate that acute HCV infection induces early changes in the abundance of specific plasma miRNAs that may affect the host response to HCV infection.