Phylogenetic clustering networks among heterosexual migrants with new HIV diagnoses post-migration in Australia

Background

It is estimated that approximately half of new HIV diagnoses among heterosexual migrants in Victoria, Australia, were acquired post-migration. We investigated the characteristics of phylogenetic clusters in notified cases of HIV among heterosexual migrants.

Methods

Partial HIV pol sequences obtained from routine clinical genotype tests were linked to Victorian HIV notifications with the following exposures listed on the notification form: heterosexual sexual contact, injecting drug use, bisexual sexual contact, male-to male sexual contact or heterosexual sexual contact in combination with injecting drug use, unknown exposure. Those with heterosexual sexual contact as the only exposure were the focus of this study, with the other exposures included to better understand transmission networks. Additional reference sequences were extracted from the Los Alamos database. Maximum likelihood methods were used to infer the phylogeny and the robustness of the resulting tree was assessed using bootstrap analysis. Phylogenetic clusters were defined on the basis of bootstrap and genetic distance.

Results

HIV pol sequences were available for 332 of 445 HIV notifications attributed to only heterosexual sexual contact in Victoria from 2005–2014. Forty-three phylogenetic clusters containing at least one heterosexual migrant were detected, 30 (70%) of which were pairs. The characteristics of these phylogenetic clusters varied considerably by cluster size. Pairs were more likely to be composed of people living with HIV from a single country of birth (p = 0.032). Larger clusters (n≥3) were more likely to contain people born in Australian/New Zealand (p = 0.002), migrants from more than one country of birth (p = 0.013) and viral subtype-B, the most common subtype in Australia (p = 0.006). Pairs were significantly more likely to contain females (p = 0.037) and less likely to include HIV diagnoses with male-to-male sexual contact reported as a possible exposure (p<0.001) compared to larger clusters (n≥3).

Conclusion

Migrants appear to be at elevated risk of HIV acquisition, in part due to intimate relationships between migrants from the same country of origin, and in part due to risks associated with the broader Australian HIV epidemic. However, there was no evidence of large transmission clusters driven by heterosexual transmission between migrants. A multipronged approach to prevention of HIV among migrants is warranted.

Measuring hepatitis C virus elimination as a public health threat: Beyond global targets

An increasing number of countries are committing to meet the World Health Organization (WHO) targets to eliminate hepatitis C virus (HCV) as a public health threat by 2030. These include service coverage targets (90% diagnosed and 80% of diagnosed patients treated) and impact targets (80% and 65% reductions in incidence and mortality, respectively, compared to 2015 levels). Currently, a dozen countries are on track to reach 2030 WHO HCV targets. However, while striving for the WHO targets is important, it should be recognized that progress on impact targets is derived from mathematical models projecting decreases in incidence and mortality on a global scale. Despite HCV treatment access in many counties for a number of years, limited empirical data are available to evaluate progress towards elimination. In some countries, substantial incidence and mortality reductions based on reaching the WHO service coverage targets may be unachievable. For example, in countries with ageing hepatitis C-infected populations, even if they have a quality hepatitis C response, high hepatitis C-related morbidity at baseline may not be reversible even with increased HCV treatment uptake and diagnosis. Finally, WHO targets are not necessarily easily or reliably measurable. Measuring relative impact targets requires high-quality data at baseline (ie 2015) and longitudinal data to assess temporal trends. In this commentary, we propose alternative additional measures to track progress on reducing the HCV burden, offer examples where the WHO targets may not be informative or achievable, and potential practical solutions.

Australia needs to increase testing to achieve hepatitis C elimination

Objectives

To assess progress in Australia toward the 2030 WHO hepatitis C elimination targets two years after the introduction of highly effective direct‐acting antiviral (DAA) treatments.

Design

Analysis of quarterly data on government‐subsidised hepatitis C RNA testing and hepatitis C treatment in Australia, January 2013 – June 2018. Changes in testing and treatment levels associated with DAA availability were assessed in an autoregressive integrated moving average (ARIMA) statistical model, and the impact by 2030 of different levels of testing and treatment were estimated using a mathematical model.

Major outcome measures

Hepatitis C prevalence among people who inject drugs; annual hepatitis C incidence relative to 2015 levels; projections for the hepatitis C care cascade in 2030.

Results

The mean annual number of treatments initiated for people with hepatitis C increased from 6747 during 2013–2015 (before the introduction of DAAs) to 28 022 during 2016–18; the mean annual number of diagnostic RNA tests increased from 17 385 to 23 819. If current trends in testing and treatment continue (ie, 2018 testing numbers are maintained but treatment numbers decline by 50%), it is projected that by 2030 only 72% of infected people would be treated (by 2025 all people diagnosed with hepatitis C would be treated). The incidence of hepatitis C in 2030 would be 59% lower than in 2015, well short of the WHO target of an 80% reduction. The identification and testing of people exposed to hepatitis C must be increased by at least 50% for Australia to reach the WHO elimination targets.

Conclusion

Hepatitis C elimination programs in Australia should focus on increasing testing rates and linkage with care to maintain adequate levels of treatment.

Staying hepatitis C negative: A systematic review and meta-analysis of cure and reinfection in people who inject drugs

BACKGROUND AND AIMS

Direct-acting antivirals (DAAs) are highly effective in treating hepatitis C. However, there is concern that cure rates may be lower, and reinfection rates higher, among people who inject drugs. We conducted a systematic review of treatment outcomes achieved with DAAs in  people who inject drugs (PWID).

METHODS

A search strategy was used to identify studies that reported sustained viral response (SVR), treatment discontinuation, adherence or reinfection in recent PWID and/or opioid substitution therapy (OST) recipients. Study quality was assessed using the Newcastle-Ottawa Scale. Meta-analysis of proportions was used to estimate pooled SVR and treatment discontinuation rates. The pooled relative risk of achieving SVR and pooled reinfection rate were calculated using generalized mixed effects linear models.

RESULTS

The search identified 8075 references; 26 were eligible for inclusion. The pooled SVR for recent PWID was 88% (95% CI, 83%-92%) and 91% (95% CI 88%-95%) for OST recipients. The relative risk of achieving SVR for recent PWID compared to non-recent PWID was 0.99 (95% CI, 0.94-1.06). The pooled treatment discontinuation was 2% (95% CI, 1%-4%) for both recent PWID and OST recipients. Amongst recent PWID, the pooled incidence of reinfection was 1.94 per 100 person years (95% CI, 0.87-4.32). In OST recipients, the incidence of reinfection was 0.55 per 100 person years (95% CI, 0.17-1.76).

CONCLUSIONS

Treatment outcomes were similar in recent PWID compared to non-PWID treated with DAAs. People who report recent injecting or OST recipients should not be excluded from hepatitis C treatment.

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.

Linkage and retention in HCV care for HIV-infected populations: early data from the DAA era

Introduction

There is currently no published data on the effectiveness of DAA treatment for elimination of HCV infection in HIV‐infected populations at a population level. However, a number of relevant studies and initiatives are emerging. This research aims to report cascade of care data for emerging HCV elimination initiatives and studies that are currently being evaluated in HIV/HCV co‐infected populations in the context of implementation science theory.

Methods

HCV elimination initiatives and studies in HIV co‐infected populations that are currently underway were identified. Context, intervention characteristics and cascade of care data were synthesized in the context of implementation science frameworks.

Results

Seven HCV elimination initiatives and studies were identified in HIV co‐infected populations, mainly operating in high‐income countries. Four were focused mainly on HCV elimination in HIV‐infected gay and bisexual men (GBM), and three included a combination of people who inject drugs (PWID), GBM and other HIV‐infected populations. None were evaluating treatment delivery in incarcerated populations. Overall, HCV RNA was detected in 4894 HIV‐infected participants (range within studies: 297 to 994): 48% of these initiated HCV treatment (range: 21% to 85%; within studies from a period where DAAs were broadly available the total is 57%, range: 36% to 74%). Among studies with treatment completion data, 96% of 1109 initiating treatment completed treatment (range: 94% to 99%). Among those who could be assessed for sustained virological response at 12 weeks (SVR12), 1631 of 1757 attained SVR12 (93%, range: 86% to 98%).

Conclusions

Early results from emerging research on HCV elimination in HIV‐infected populations suggest that HCV treatment uptake is higher than reported levels prior to DAA treatment availability, but approximately half of patients remain untreated. These results are among diagnosed populations and additional effort is required to increase diagnosis rates. Among those who have initiated treatment, completion and SVR rates are promising. More data are required in order to evaluate the effectiveness of these elimination programmes in the long term, assess which intervention components are effective, and whether they need to be tailored to particular population groups.

Treatment access is only the first step to hepatitis C elimination: experience of universal anti-viral treatment access in Australia

BACKGROUND

Global targets to eliminate hepatitis C (HCV) might be met by sustained treatment uptake.

AIM

To describe factors facilitating HCV treatment uptake and potential challenges to sustaining treatment levels after universal access to direct-acting anti-virals (DAA) across Australia.

METHODS

We analysed national Pharmaceutical Benefits Scheme data to determine the number of DAA prescriptions commenced before and after universal access from March 2016 to June 2017. We inferred facilitators and barriers to treatment uptake, and challenges that will prevent local and global jurisdictions reaching elimination targets.

RESULTS

In 2016, 32 877 individuals (14% of people living with HCV in Australia) commenced HCV DAA treatment, and 34 952 (15%) individuals commenced treatment in the first year of universal access. Treatment uptake peaked at 13 109 DAA commencements per quarter immediately after universal access, but more than halved (to 5320 in 2017 Q2) within 12 months. General practitioners have written 24% of all prescriptions but with a significantly increased proportion over time (9% in 2016 Q1 to 37% in 2017 Q2). In contrast, hepatology or infectious diseases specialists have written a declining share from 74% to 38% during the same period. General practitioners provided a greater proportion (47%) of care in regional/remote areas than major cities.

CONCLUSIONS

Broad treatment access led to rapid initial increases in treatment uptake, but this uptake has not been sustained. Our results suggest achieving global elimination targets requires more than treatment availability: people with HCV need easy access to testing and linkage to care in community settings employing a diverse prescriber base.

Incarceration history and risk of HIV and hepatitis C virus acquisition among people who inject drugs: a systematic review and meta-analysis

BACKGROUND

People who inject drugs (PWID) experience a high prevalence of incarceration and might be at high risk of HIV and hepatitis C virus (HCV) infection during or after incarceration. We aimed to assess whether incarceration history elevates HIV or HCV acquisition risk among PWID.

METHODS

In this systematic review and meta-analysis, we searched MEDLINE, Embase, and PsycINFO databases for studies in any language published from Jan 1, 2000 until June 13, 2017 assessing HIV or HCV incidence among PWID. We included studies that measured HIV or HCV incidence among community-recruited PWID. We included only studies reporting original results and excluded studies that evaluated incident infections by self-report. We contacted authors of cohort studies that met the inclusion or exclusion criteria, but that did not report on the outcomes of interest, to request data. We extracted and pooled data from the included studies using random-effects meta-analyses to quantify the associations between recent (past 3, 6, or 12 months or since last follow-up) or past incarceration and HIV or HCV acquisition (primary infection or reinfection) risk among PWID. We assessed the risk of bias of included studies using the Newcastle-Ottawa Scale. Between-study heterogeneity was evaluated using the I2 statistic and the P-value for heterogeneity.

FINDINGS

We included published results from 20 studies and unpublished results from 21 studies. These studies originated from Australasia, western and eastern Europe, North and Latin America, and east and southeast Asia. Recent incarceration was associated with an 81% (relative risk [RR] 1·81, 95% CI 1·40-2·34) increase in HIV acquisition risk, with moderate heterogeneity between studies (I2=63·5%; p=0·001), and a 62% (RR 1·62, 95% CI 1·28-2·05) increase in HCV acquisition risk, also with moderate heterogeneity between studies (I2=57·3%; p=0·002). Past incarceration was associated with a 25% increase in HIV (RR 1·25, 95% CI 0·94-1·65) and a 21% increase in HCV (1·21, 1·02-1·43) acquisition risk.

INTERPRETATION

Incarceration is associated with substantial short-term increases in HIV and HCV acquisition risk among PWID and could be a significant driver of HCV and HIV transmission among PWID. These findings support the need for developing novel interventions to minimise the risk of HCV and HIV acquisition, including addressing structural risks associated with drug laws and excessive incarceration of PWID.

FUNDING

Engineering and Physical Sciences Research Council, National Institute for Health Research, National Institutes of Health.

Eliminating hepatitis C: The importance of frequent testing of people who inject drugs in high-prevalence settings

Modelling suggests that more frequent screening of people who inject drugs (PWID) and an improved care cascade are required to achieve the WHO hepatitis C virus (HCV) elimination target of an 80% reduction in incidence by 2030. We determined the testing frequencies (2-yearly, annually, 6-monthly and 3-monthly) and retention in care required among PWID to achieve the HCV incidence reduction target through treatment as prevention in low (25%), medium (50%) and high (75%) chronic HCV prevalence settings. Mathematical modelling of HCV transmission among PWID, capturing testing, treatment and other features of the care cascade were employed. In low-prevalence settings, 2-yearly antibody testing of PWID was estimated to reach the elimination target by 2027-2030 depending on retention in care, with annual testing reducing the time by up to 3 years. In medium-prevalence settings, if close to 90% testing coverage were achieved, then annual antibody testing of PWID would be sufficient. If testing coverage were lower (80%), 6-monthly antibody testing with at least 70% retention in care or annual HCV RNA/cAg testing would be required. In high-prevalence settings, even 3-monthly HCV RNA/cAg testing of PWID was unable to achieve the incidence reduction target. Thus, for geographical areas or subpopulations with high prevalence, WHO incidence targets are unlikely to be met without 3-monthly RNA/cAg testing accompanied by other prevention measures. Novel testing strategies, such as rapid point-of-care antibody testing or replacing antibody testing with RNA/cAg tests as a screening tool, can provide additional population-level impacts to compensate for imperfect follow-up or testing coverage.

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.

Heterogeneity in hepatitis C treatment prescribing and uptake in Australia: a geospatial analysis of a year of unrestricted treatment access

Background and aim

Direct-acting antiviral (DAA) treatments became available for all people living with hepatitis C virus (HCV) in Australia in March 2016. We assess variations in treatment rates and prescribing patterns across Australia's 338 Statistical Area 3 (SA3) geographical units.

Methods

Geocoded DAA treatment initiation data were analysed for the period 1 March 2016 to 30 June 2017. Regression models tested associations between the population demographics and healthcare service coverage of geographical areas and (a) their treatment rates; and (b) the proportion of prescriptions written by specialists compared to non-specialists.

Results

Across the 320 areas (95%) recording treatments, a median 76 (interquartile range [IQR] 35-207, range 4-3834) per 100,000 were initiated, corresponding to an estimated median 7.9% (IQR 2.9-23.6%, range 0-100%) treatment uptake. Major cities, areas of socioeconomic advantage and areas with lower proportions of the population born overseas had the highest per capita treatment rates. Non-specialists prescribed 46% (20,323/44,382) of treatment initiations. Prescriptions were written by non-specialists only in 163 areas (51%), while in other areas a median 40.0% (IQR 21.8-62.5%) of prescriptions were written by non-specialists. Non-specialist prescribing was higher in regional areas, as well as areas that had greater proportions of Indigenous Australians.

Conclusions

High national-level treatment uptake of 20% in Australia masks underlying health system limitations; more than half of geographical areas may have treated less than 8% of people living with HCV. Areas of socioeconomic disadvantage and areas with a higher proportion of the population born overseas may need targeting with interventions to improve treatment uptake.

The role of living context in prescription opioid injection and the associated risk of hepatitis C infection

BACKGROUND AND AIMS

Prescription opioid injection (POI) is a leading risk factor for hepatitis C virus (HCV). Residential context relates to high‐risk injection behaviour. This study assessed whether residence in the inner city (versus surrounding areas in Montréal Island) modified the effects of correlates of POI or the relationship between POI and HCV incidence.

DESIGN

Prospective cohort study.

SETTING

Montréal, Canada.

PARTICIPANTS

A total of 854 people who inject drugs (18% female, 25% age < 30 years), living on Montréal Island, were interviewed every 3–6 months from 2004 to 2012.

MEASUREMENTS

Study visits included HCV antibody testing and an interviewer‐administered questionnaire. Generalized estimating equations were used to test whether place of residence modified the effects of correlates of POI. Cox regression was used to test whether place of residence modified the relationship between POI and HCV incidence.

FINDINGS

At baseline, inner‐city participants were more likely to report POI in the past month (40 versus 25%, P < 0.001). The association between POI and heroin injection, syringe sharing and sharing of injecting equipment varied according to place of residence and was greater in the inner city. The hazard of HCV infection associated with POI was greater among inner‐city participants compared to those in the surrounding areas [adjusted hazard ratio (HR) = 3.38, 95% confidence interval (CI) = 1.88–6.07 versus HR = 1.26, 95% CI = 0.65–2.42, P = 0.025].

CONCLUSIONS

Among people who inject prescription opioids in Montréal, Canada, those who live in inner‐city areas are more likely to engage in injecting‐related risk behaviours and have a higher risk of hepatitis C virus infection than those who live in the suburbs.

Venue-Based Networks May Underpin HCV Transmissions amongst HIV-Infected Gay and Bisexual Men

Background

This study aimed to investigate the potential influence of venue-based networks on HCV transmission in HIV-positive gay and bisexual men (GBM).

Methods

This was a prospectively recruited cohort of HIV-infected GBM with recently-acquired HCV infection resident in Melbourne and Sydney. Clinical and demographic data were collected together with blood samples for HCV sequencing. Phylogenies were inferred and clusters of individuals infected with HCV with genetic sequence homology were identified. Venues used for sourcing sexual partners were identified; sourcing partners from the same venue was considered a potential social link. Using the Jaccard similarity coefficient, associations were identified between the network of sites where men sourced sex partners and transmission relationships as defined by phylogenetic clustering.

Results

Forty individuals were recruited, of whom 62.5% were considered to have sexually- and 37.5% IDU-acquired HCV. Venue use was consistent with men being members of a more sexually adventurous gay community subculture. Six phylogenetically-determined pairs or clusters were identified, comprising fifteen (15/28, 53.6%) individuals. Participants belonging to phylogenetic clusters were observed within the same networks. There was a significant correlation between the network and phylogenetic clustering when both cities were considered simultaneously (p = 0.005), raising the possibility that social connections may be important for HCV transmissions.

Conclusions

Venue-based network elicitation is a promising approach for elucidating HCV transmissions amongst HIV-infected GBM. Public health approaches targeting individuals and venues prominent within networks may reduce onward HCV transmission.

Response to treatment following recently acquired hepatitis C virus infection in a multicentre collaborative cohort

Pegylated interferon therapy is highly effective in recently acquired HCV. The optimal timing of treatment, regimen and influence of host factors remains unclear. We aimed to measure sustained virological response (SVR) during recent HCV infection and identify predictors of response. Data were from five prospective cohorts of high-risk individuals in Australia, Canada, Germany and the United States. Individuals with acute or early chronic HCV who commenced pegylated interferon therapy were included. The main outcome was SVR, and predictors were assessed using logistic regression. Among 516 with documented recent HCV infection, 237 were treated (pegylated interferon n = 161; pegylated interferon/ribavirin n = 76) (30% female, median age 35 years, 56% ever injected drugs, median duration of infection 6.2 months). Sixteen per cent (n = 38) were HIV/HCV co-infected. SVR among those with HCV mono-infection was 64% by intention to treat; SVR was 68% among HCV/HIV co-infection. Independent predictors of SVR in HCV mono-infection were duration of HCV infection (the odds of SVR declined by 8% per month of infection, aOR 0.92, 95% CI 0.85-0.99, P = 0.033), IFNL4 genotype (adjusted OR 2.27, 95% CI 1.13-4.56, P = 0.021), baseline HCV RNA <400 000 IU/mL (aOR 2.06, 95% CI 1.03-4.12, P = 0.041) and age ≥40 years (vs <30: aOR 2.92, 95% CI 1.31-6.49, P = 0.009), with no difference by drug regimen, HCV genotype, symptomatic infection or gender. The effect of infection duration on odds of SVR was greater among genotype-1 infection. Interferon-based HCV treatment is highly effective in recent HCV infection. Duration of infection, IFNL4 genotype and baseline HCV RNA levels can predict virological response and may inform clinical decision-making.

Many hepatitis C reinfections that spontaneously clear may be undetected: Markov-chain Monte Carlo analysis of observational study data

Hepatitis C virus (HCV) reinfection rates are probably underestimated due to reinfection episodes occurring between study visits. A Markov model of HCV reinfection and spontaneous clearance was fitted to empirical data. Bayesian post-estimation was used to project reinfection rates, reinfection spontaneous clearance probability and duration of reinfection. Uniform prior probability distributions were assumed for reinfection rate (more than 0), spontaneous clearance probability (0-1) and duration (0.25-6.00 months). Model estimates were 104 per 100 person-years (95% CrI: 21-344), 0.84 (95% CrI: 0.59-0.98) and 1.3 months (95% CrI: 0.3-4.1) for reinfection rate, spontaneous clearance probability and duration, respectively. Simulation studies were used to assess model validity, demonstrating that the Bayesian model estimates provided useful information about the possible sources and magnitude of bias in epidemiological estimates of reinfection rates, probability of reinfection clearance and duration or reinfection. The quality of the Bayesian estimates improved for larger samples and shorter test intervals. Uncertainty in model estimates notwithstanding, findings suggest that HCV reinfections frequently and quickly result in spontaneous clearance, with many reinfection events going unobserved.

Factors associated with hepatitis C virus RNA levels in early chronic infection: the InC3 study

Improved understanding of natural history of hepatitis C virus (HCV) RNA levels in chronic infection provides enhanced insights into immunopathogenesis of HCV and has implications for the clinical management of chronic HCV infection. This study assessed factors associated with HCV RNA levels during early chronic infection in a population with well-defined early chronic HCV infection. Data were from an international collaboration of nine prospective cohorts studying acute HCV infection (InC(3) study). Individuals with persistent HCV and detectable HCV RNA during early chronic infection (one year [±4 months] postinfection) were included. Distribution of HCV RNA levels during early chronic infection was compared by selected host and virological factors. A total of 308 individuals were included. Median HCV RNA levels were significantly higher among males (vs females; 5.15 vs 4.74 log IU/mL; P < 0.01) and among individuals with HIV co-infection (vs no HIV; 5.89 vs 4.86; P = 0.02). In adjusted logistic regression, male sex (vs female, adjusted odds ratio [AOR]: 1.93; 95%CI: 1.01, 3.69), interferon lambda 4 (IFNL4) rs12979860 CC genotype (vs TT/CT; AOR: 2.48; 95%CI: 1.42, 4.35), HIV co-infection (vs no HIV; AOR: 3.27; 95%CI: 1.35, 7.93) and HCV genotype G2 (vs G3; AOR: 5.40; 95%CI: 1.63, 17.84) were independently associated with high HCV RNA levels (>5.6 log IU/mL = 400 000 IU/mL). In conclusion, this study demonstrated that IFNL4 rs12979860 CC genotype, male sex, HIV co-infection and HCV genotype G2 are associated with high HCV RNA levels in early chronic infection. These factors exert their role as early as one year following infection.

Hepatitis C Virus Reinfection and Spontaneous Clearance of Reinfection--the InC3 Study

BACKGROUND

We aimed to characterize the natural history of hepatitis C virus (HCV) reinfection and spontaneous clearance following reinfection (reclearance), including predictors of HCV reclearance.

METHODS

Data were synthesized from the 9 prospective cohorts of the International Collaboration of Incident Human Immunodeficiency Virus and HCV in Injecting Cohorts study, which evaluated HCV infection outcomes among people who inject drugs. Participants with primary HCV infection were classified as having achieved viral suppression if they had negative results of at least 1 subsequent HCV RNA test. Those with positive results of an HCV RNA test following viral suppression were investigated for reinfection. Viral sequence analysis was used to identify reinfection (defined as detection of heterologous virus with no subsequent detection of the original viral strain).

RESULTS

Among 591 participants with acute primary HCV infection, 118 were investigated for reinfection. Twenty-eight participants were reinfected (12.3 cases/100 person-years; 95% confidence interval [CI], 8.5-17.8). Peak HCV RNA level was lower during reinfection than primary infection (P = .011). The proportion of individuals with reclearance 6 months after reinfection was 52% (95% CI, 33%-73%). After adjustment for study site, females with the IFNL4 (formerly IFNL3 and IL28B) rs12979860 CC genotype detected were more likely to have reclearance (hazard ratio, 4.16; 95% CI, 1.24-13.94; P = .021).

CONCLUSIONS

Sex and IFNL4 genotype are associated with spontaneous clearance after reinfection.

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

BACKGROUND

Understanding the patterns of HCV RNA levels during acute hepatitis C virus (HCV) infection provides insights into immunopathogenesis and is important for vaccine design. This study evaluated patterns of HCV RNA levels and associated factors among individuals with acute infection.

METHODS

Data were from an international collaboration of nine prospective cohorts of acute HCV (InC3 Study). Participants with well-characterized acute HCV infection (detected within three months post-infection and interval between the peak and subsequent HCV RNA levels ≤ 120 days) were categorised by a priori-defined patterns of HCV RNA levels: i) spontaneous clearance, ii) partial viral control with persistence (≥ 1 log IU/mL decline in HCV RNA levels following peak) and iii) viral plateau with persistence (increase or <1 log IU/mL decline in HCV RNA levels following peak). Factors associated with HCV RNA patterns were assessed using multinomial logistic regression.

RESULTS

Among 643 individuals with acute HCV, 162 with well-characterized acute HCV were identified: spontaneous clearance (32%), partial viral control with persistence (27%), and viral plateau with persistence (41%). HCV RNA levels reached a high viraemic phase within two months following infection, with higher levels in the spontaneous clearance and partial viral control groups, compared to the viral plateau group (median: 6.0, 6.2, 5.3 log IU/mL, respectively; P = 0.018). In the two groups with persistence, Interferon lambda 3 (IFNL3) CC genotype was independently associated with partial viral control compared to viral plateau (adjusted odds ratio [AOR]: 2.75; 95%CI: 1.08, 7.02). In the two groups with viral control, female sex was independently associated with spontaneous clearance compared to partial viral control (AOR: 2.86; 95%CI: 1.04, 7.83).

CONCLUSIONS

Among individuals with acute HCV, a spectrum of HCV RNA patterns is evident. IFNL3 CC genotype is associated with initial viral control, while female sex is associated with ultimate spontaneous clearance.