Hepatitis C virus incidence among young street-involved IDUs in relation to injection experience

Hepatitis C treatment uptake among people who inject drugs in Oslo, Norway: A registry-based study

BACKGROUND

Improving HCV treatment uptake among people who inject drugs (PWID) is crucial to achieving the WHO elimination targets. The aims were to evaluate HCV treatment uptake and HCV RNA prevalence in a large cohort of PWID in Norway.

METHODS

Registry-based observational study where all users of the City of Oslo's low-threshold social and health services for PWID between 2010-2016 (n = 5330) were linked to HCV notifications (1990-2019) and dispensions of HCV treatment, opioid agonist treatment (OAT) and benzodiazepines (2004-2019). Cases were weighted to account for spontaneous HCV clearance. Treatment rates were calculated using person-time of observation, and factors associated with treatment uptake were analysed using logistic regression. HCV RNA prevalence was estimated among individuals alive by the end of 2019.

RESULTS

Among 2436 participants with chronic HCV infection (mean age 46.8 years, 30.7% female, 73.3% OAT), 1118 (45.9%) had received HCV treatment between 2010-2019 (88.7% DAA-based). Treatment rates increased from 1.4/100 PY (95% CI 1.1-1.8) in the pre-DAA period (2010-2013) to 3.5/100 PY (95% CI 3.0-4.0) in the early DAA period (2014-2016; fibrosis restrictions) and 18.4/100 PY (95% CI 17.2-19.7) in the late DAA period (2017-2019; no restrictions). Treatment rates for 2018 and 2019 exceeded a previously modelled elimination threshold of 50/1000 PWID. Treatment uptake was less likely among women (aOR 0.74; 95% CI 0.62-0.89) and those aged 40-49 years (aOR 0.74; 95% CI 0.56-0.97), and more likely among participants with current OAT (aOR 1.21; 95% CI 1.01-1.45). The estimated HCV RNA prevalence by the end of 2019 was 23.6% (95% CI 22.3-24.9).

CONCLUSION

Although HCV treatment uptake among PWID increased, strategies to improve treatment among women and individuals not engaged in OAT should be addressed.

Investigating the sociodemographic and behavioural factors associated with hepatitis C virus testing amongst people who inject drugs in England, Wales and Northern Ireland: A quantitative cross-sectional analysis

BACKGROUND

Hepatitis C virus (HCV) transmission in the UK is driven by injecting drug use. We explore HCV testing uptake amongst people who inject drugs (PWID) in England, Wales and Northern Ireland, and identify factors associated with i) ever having an HCV test amongst people who have ever injected drugs, and ii) recently having an HCV test (within the current or previous year) amongst people who currently inject drugs (reported injecting drugs within the last year).

METHODS

We analysed data from the 2019 'Unlinked Anonymous Monitoring Survey' of PWID, using logistic regression.

RESULTS

Of 3,127 PWID, 2,065 reported injecting drugs within the last year. Most (86.7%) PWID had a lifetime history of HCV testing. In multivariable analysis, higher odds of ever testing were associated with: female sex (aOR=1.54; 95%CI 1.11-2.14), injecting duration ≥3 years (aOR=2.94; 95%CI 2.13-4.05), ever receiving used needles/syringes (aOR=1.74; 95%CI 1.29-2.36), ever being on opioid agonist treatment (aOR=2.91; 95%CI 2.01-4.21), ever being imprisoned (aOR=1.86; 95%CI 1.40-2.48) and ever being homeless (aOR=1.54; 95%CI 1.14-2.07). Amongst PWID who had injected drugs within the last year, 49.9% had recently undertaken an HCV test. After adjustment, factors associated with higher odds of undertaking a recent HCV test included: injecting crack in the last year (aOR=1.29; 95%CI 1.03-1.61), experiencing a non-fatal overdose in the last year (aOR=1.39; 95%CI 1.05-1.85), ever being on opioid agonist treatment (aOR=1.48; 95%CI 0.97-2.25), receiving HCV information in the last year (aOR=1.99; 95%CI 1.49-2.65) and using a healthcare service in the last year (aOR=1.80; 95%CI 1.21-2.67).

CONCLUSION

Results suggest that PWID who have experienced homelessness and incarceration - amongst the most vulnerable and marginalised in the PWID population - are engaging with HCV testing, but overall there remain missed testing opportunities. Recent initiates to injecting have highest HCV infection risk but lower odds of testing, and peer-education may help target this group.

Modeling Hepatitis C Elimination Among People Who Inject Drugs in New Hampshire

Importance

The success of direct-acting antiviral therapies for chronic hepatitis C virus (HCV) infection led the World Health Organization to set elimination targets by 2030. For the United States to achieve these benchmarks, public health responses must target high-risk populations, such as people who inject drugs (PWID), a group with high rates of HCV incidence and low rates of treatment uptake.

Objective

To evaluate potential improvements in the HCV care cascade among PWID, focusing on improved testing, treatment uptake, and access to harm reduction.

Design, Setting, and Participants

This decision analytic model used a differential equation-based dynamic transmission model based on data from New Hampshire, an illustrative state with a large number of PWID and limited HCV treatment infrastructure. Surveillance data through 2020 was used for model parameterization, and the final analysis was conducted in May 2021.

Main Outcomes and Measures

Model forecasts of chronic HCV cases and advanced-stage HCV outcomes from 2022 to 2045.

Results

A total of 6 scenarios were tested: (1) the base case, (2) improved harm reduction, (3) improved testing, (4) improved treatment, (5) improved testing and treatment, and (6) improved testing, treatment, and harm reduction. All scenarios with improved testing, treatment uptake, and/or access to harm reduction were associated with decreases in forecasted HCV prevalence and HCV-associated mortality compared with the base case. Improving harm reduction, testing, and treatment individually were forecast to reduce prevalence of HCV in 2045 from 69.7% in the base case to 62.8%, 45.7%, and 35.5%, respectively. Combining treatment and testing improvements was associated with a 2045 prevalence of 0.3%; adding harm reduction improvements was associated with further reductions in prevalence forecasts (to 0.2%), with fewer total treatments (10 960 vs 13 219 from 2022-2045).

Conclusions and Relevance

In this modeling study, no single intervention was projected to achieve World Health Organization HCV elimination targets. Scenarios with improvements in both testing and treatment were associated with a prevalence of less than 3% by 2030 and achieved elimination targets. Adding improvements in harm reduction was associated with faster reductions in prevalence and fewer treatments.

High prevalence of hepatitis C virus infection and low level of awareness among people who recently started injecting drugs in a cross-sectional study in Germany, 2011-2014: missed opportunities for hepatitis C testing

Background

In Germany, risk of hepatitis C virus (HCV) infection is highest among people who inject drugs (PWID). New injectors (NI) are particularly vulnerable for HCV-acquisition, but little is known about health seeking behaviour and opportunities for intervention in this group. We describe characteristics, HCV prevalence, estimated HCV incidence and awareness of HCV-status among NIs and missed opportunities for hepatitis C testing.

Methods

People who had injected drugs in the last 12 months were recruited into a cross-sectional serobehavioural study using respondent-driven sampling in 8 German cities, 2011–2014. Data on sociodemographic characteristics, previous HCV testing and access to care were collected through questionnaire-based interviews. Capillary blood was tested for HCV. People injecting drugs < 5 years were considered NI.

Results

Of 2059 participants with available information on duration of injection drug use, 232 (11% were NI. Estimated HCV incidence among NI was 19.6 infections/100 person years at risk (95% CI 16–24). Thirty-six percent of NI were HCV-positive (thereof 76% with detectable RNA) and 41% of those HCV-positive were unaware of their HCV-status. Overall, 27% of NI reported never having been HCV-tested. Of NI with available information, more than 80% had attended low-threshold drug services in the last 30 days, 24% were released from prison in the last 12 months and medical care was most commonly accessed in hospitals, opioid substitution therapy (OST)-practices, practices without OST and prison hospitals.

Conclusion

We found high HCV-positivity and low HCV-status awareness among NI, often with missed opportunities for HCV-testing. To increase early diagnosis and facilitate treatment, HCV-testing should be offered in all facilities, where NI can be reached, especially low-threshold drug services and addiction therapy, but also prisons, hospitals and practices without OST.

Correlates of hepatitis C viral clustering among people who inject drugs in Baltimore

This study examines correlates of hepatitis C virus (HCV) genetic clustering among community-recruited people who inject drugs enrolled in the AIDS Linked to the IntraVenous Experience cohort in Baltimore between 1988 and 1989. HCV RNA was extracted and the core/envelope-1 region was sequenced. Clusters were identified from maximum likelihood trees with 1000 bootstrap replicates using a 70% aLRT and a 4% genetic-distance threshold in Cluster Picker. Overall, 46% of participants were in a cluster, including 122 genotype-1a and 36 genotype-1b clusters with an average of 2-3 genetically linked HCV infections. The largest cluster consists of 9 participants. In univariable analysis, black race (PR = 1.66 [95% CI: 1.12-2.45]), age <35 years (PR = 1.18 [95% CI: 1.02-1.37]), and injection drug use of cocaine alone (PR = 1.30 [95% CI: 1.02-1.65]) were significantly associated with being in a cluster. Conversely, a history of medication-associated treatment (MAT) was negatively associated with being in a cluster (PR = 0.82 [95% CI: 0.71-0.95]). In multivariable analysis, black race (APR = 1.62 [95% CI: 1.11-2.38]) remained independently associated being in a cluster while MAT (APR = 0.85 [95% CI: 0.74-0.99]) remained negatively associated with clustering. Our findings suggest strong locally-propagated transmission networks during the early epidemic that was driven by younger PWID. In light of the current opioid epidemic in the US, these findings suggest an urgent need for preventive interventions to mitigate the growth of large HCV transmission networks.

Factors Associated with Frequency of Recent Initiation of Others into Injection Drug Use Among People Who Inject Drugs in Los Angeles and San Francisco, CA, USA, 2016-17

Objective: Drug injection initiation is often assisted by a person who injects drugs (PWID). How often PWID provide this assistance has not been examined. We examine frequency of injection initiation assistance and factors associated with high (4+) and low frequency (1-3) initiation assistance as compared to no initiation assistance among PWID. Methods: Participants were 979 Californian PWID. PWID were interviewed about providing injection initiation assistance in the last 6 months among other items. Multinomial regression analysis was used to examine factors associated with levels of frequency of injection initiation assistance. Results: Among participants, 132 (14%) had initiated 784 people into injection (mean = 5.94 [standard deviation = 20.13]; median = 2, interquartile range = 1,4) in the last 6 months. PWID engaged in high frequency initiation (26% of sample) assisted 662 new initiates (84% of total). Using multinomial regression analysis with no initiating as the referent group, we found that high frequency initiating was statistically associated with higher injection frequency, having a paying sex partner, taking someone to a shooting gallery, and providing injection assistance. Lower frequency initiation was statistically associated with having a paying sex partner, illegal income source, and providing injection assistance. Conclusion: Differences between high and low frequency initiators were not found. Sex work and assisting with drug injection were linked to initiating others. Individual-level interventions that reduce this behavior among PWID and structural interventions such as safe consumption sites and opioid medication treatments that interrupt the social process of injection initiation should be considered as ways to reduce injection initiations.

Hepatitis C elimination among people who inject drugs: Challenges and recommendations for action within a health systems framework

The burden of hepatitis C infection is considerable among people who inject drugs (PWID), with an estimated prevalence of 39%, representing an estimated 6.1 million people who have recently injected drugs living with hepatitis C infection. As such, PWID are a priority population for enhancing prevention, testing, linkage to care, treatment and follow-up care in order to meet World Health Organization (WHO) hepatitis C elimination goals by 2030. There are many barriers to enhancing hepatitis C prevention and care among PWID including poor global coverage of harm reduction services, restrictive drug policies and criminalization of drug use, poor access to health services, low hepatitis C testing, linkage to care and treatment, restrictions for accessing DAA therapy, and the lack of national strategies and government investment to support WHO elimination goals. On 5 September 2017, the International Network of Hepatitis in Substance Users (INHSU) held a roundtable panel of international experts to discuss remaining challenges and future priorities for action from a health systems perspective. The WHO health systems framework comprises six core components: service delivery, health workforce, health information systems, medical procurement, health systems financing, and leadership and governance. Communication has been proposed as a seventh key element which promotes the central role of affected community engagement. This review paper presents recommended strategies for eliminating hepatitis C as a major public health threat among PWID and outlines future priorities for action within a health systems framework.

A comparison of two biological markers of recent hepatitis C virus (HCV) infection: implications for the monitoring of interventions and strategies to reduce HCV transmission among people who inject drugs

BackgroundMonitoring hepatitis C virus (HCV) incidence is important for assessing intervention impact. Longitudinal studies of people who inject drugs (PWID), using repeated biological tests, are costly; alternatively, incidence can be estimated using biological markers of recent infection in cross-sectional studies.AimWe aimed to compare incidence estimates obtained from two different biological markers of recent infection in a cross-sectional study to inform monitoring approaches for HCV elimination strategies.MethodSamples from an unlinked anonymous bio-behavioural survey of PWID were tested for two recent infection markers: HCV RNA with anti-HCV negative ('RNA') and low-avidity anti-HCV with HCV RNA present ('avidity'). These two markers were used separately and in combination to estimate HCV incidence.ResultsBetween 2011 and 2013, 2,816 anti-HIV-negative PWID (25% female) who had injected during the preceding year were either HCV-negative or had one of the two markers of recent infection: 57 (2.0%) had the RNA marker and 90 (3.2%) the avidity marker. The two markers had similar distributions of risk and demographic factors. Pooled estimated incidence was 12.3 per 100 person-years (pyrs) (95% credible interval: 8.8-17.0) and not significantly different to avidity-only (p = 0.865) and RNA-only (p = 0.691) estimates. However, the RNA marker is limited by its short duration before anti-HCV seroconversion and the avidity marker by uncertainty around its duration.ConclusionBoth markers have utility in monitoring HCV incidence among PWID. When HCV transmission is high, one marker may provide an accurate estimate of incidence; when it is low or decreasing, a combination may be required.

A large HCV transmission network enabled a fast-growing HIV outbreak in rural Indiana, 2015

Background

A high prevalence (92.3%) of hepatitis C virus (HCV) co-infection among HIV patients identified during a large HIV outbreak associated with injection of oxymorphone in Indiana prompted genetic analysis of HCV strains.

Methods

Molecular epidemiological analysis of HCV-positive samples included genotyping, sampling intra-host HVR1 variants by next-generation sequencing (NGS) and constructing transmission networks using Global Hepatitis Outbreak and Surveillance Technology (GHOST).

Findings

Results from the 492 samples indicate predominance of HCV genotypes 1a (72.2%) and 3a (20.4%), and existence of 2 major endemic NS5B clusters involving 49.8% of the sequenced strains. Among 76 HIV co-infected patients, 60.5% segregated into 2 endemic clusters. NGS analyses of 281 cases identified 826,917 unique HVR1 sequences and 51 cases of mixed subtype/genotype infections. GHOST mapped 23 transmission clusters. One large cluster (n = 130) included 50 cases infected with ≥2 subtypes/genotypes and 43 cases co-infected with HIV. Rapid strain replacement and superinfection with different strains were found among 7 of 12 cases who were followed up.

Interpretation

GHOST enabled mapping of HCV transmission networks among persons who inject drugs (PWID). Findings of numerous transmission clusters, mixed-genotype infections and rapid succession of infections with different HCV strains indicate a high rate of HCV spread. Co-localization of HIV co-infected patients in the major HCV clusters suggests that HIV dissemination was enabled by existing HCV transmission networks that likely perpetuated HCV in the community for years. Identification of transmission networks is an important step to guiding efficient public health interventions for preventing and interrupting HCV and HIV transmission among PWID.

Fund

US Centers for Disease Control and Prevention, and US state and local public health departments.

Economically Efficient Hepatitis C Virus Treatment Prioritization Improves Health Outcomes

BACKGROUND

The total cost of treating the 3 million Americans chronically infected with hepatitis C virus (HCV) represents a substantial affordability challenge requiring treatment prioritization. This study compares the health and economic outcomes of alternative treatment prioritization schedules.

METHODS

We developed a multiyear HCV treatment budget allocation model to evaluate the tradeoffs of 7 prioritization strategies. We used optimization to identify the priority schedule that maximizes population net monetary benefit (NMB). We compared prioritization schedules in terms of the number of individuals treated, the number of individuals who progress to end-stage liver disease (ESLD), and population total quality-adjusted life years (QALYs). We applied the model to the population of treatment-naive patients with a total annual HCV treatment budget of US$8.6 billion.

RESULTS

First-come, first-served (FCFS) treats the fewest people with advanced fibrosis, prevents the fewest cases of ESLD, and gains the fewest QALYs. A schedule developed from optimizing population NMB prioritizes treatment in the first year to patients with moderate to severe fibrosis who are younger than 65 years, followed by older individuals with moderate to severe fibrosis. While this strategy yields the greatest population QALYs, prioritization by disease severity alone prevents more cases of ESLD. Sensitivity analysis indicated that the differences between prioritization schedules are greater when the budget is smaller. A 10% annual treatment price reduction enabled treatment 1 year sooner to several patient subgroups, specifically older patients and those with less severe liver fibrosis.

CONCLUSION

In the absence of a sufficient budget to treat all patients, explicit prioritization targeting younger people with more severe disease first provides the greatest health benefits. We provide our spreadsheet model so that decision makers can compare health tradeoffs of different budget levels and various prioritization strategies with inputs tailored to their population.

The role of prevention strategies in achieving HCV elimination in Canada: what are the remaining challenges?

Background

The worldwide economic, health, and social consequences of drug use disorders are devastating. Injection drug use is now a major factor contributing to hepatitis C virus (HCV) transmission globally, and it is an important public health concern.

Methods

This article presents a narrative review of scientific evidence on public health strategies for HCV prevention among people who inject drugs (PWID) in Canada.

Results

A combination of public health strategies including timely HCV detection and harm reduction (mostly needle and syringe programmes and opioid substitution therapy) have helped to reduce HCV transmission among PWID. The rising prevalence of pharmaceutical opioid and methamphetamine use and associated HCV risk in several Canadian settings has prompted further innovation in harm reduction, including supervised injection facilities and low-threshold opioid substitution therapies. Further significant decreases in HCV incidence and prevalence, and in corresponding disease burden, can only be accomplished by reducing transmission among high-risk persons and enhancing access to HCV treatment for those at the greatest risk of disease progression or viral transmission. Highly effective and tolerable direct-acting antiviral therapies have transformed the landscape for HCV-infected patients and are a valuable addition to the prevention toolkit. Curing HCV-infected persons, and thus eliminating new infections, is now a real possibility.

Conclusions

Prevention strategies have not yet ended HCV transmission, and sharing of injecting equipment among PWID continues to challenge the World Health Organization goal of eliminating HCV as a global public health threat by 2030. Future needs for research, intervention implementation, and uptake in Canada are discussed.

Needle and syringe programmes and opioid substitution therapy for preventing HCV transmission among people who inject drugs: findings from a Cochrane Review and meta-analysis

AIMS

To estimate the effects of needle and syringe programmes (NSP) and opioid substitution therapy (OST), alone or in combination, for preventing acquisition of hepatitis C virus (HCV) in people who inject drugs (PWID).

METHODS

Systematic review and meta-analysis. Bibliographic databases were searched for studies measuring concurrent exposure to current OST (within the last 6 months) and/or NSP and HCV incidence among PWID. High NSP coverage was defined as regular NSP attendance or ≥ 100% coverage (receiving sufficient or greater number of needles and syringes per reported injecting frequency). Studies were assessed using the Cochrane risk of bias in non-randomized studies tool. Random-effects models were used in meta-analysis.

RESULTS

We identified 28 studies (n = 6279) in North America (13), United Kingdom (five), Europe (four), Australia (five) and China (one). Studies were at moderate (two), serious (17) critical (seven) and non-assessable risk of bias (two). Current OST is associated with 50% [risk ratio (RR) =0.50, 95% confidence interval (CI) = 0.40-0.63] reduction in HCV acquisition risk, consistent across region and with low heterogeneity (I2  = 0, P = 0.889). Weaker evidence was found for high NSP coverage (RR = 0.79, 95% CI = 0.39-1.61) with high heterogeneity (I2  = 77%, P = 0.002). After stratifying by region, high NSP coverage in Europe was associated with a 56% reduction in HCV acquisition risk (RR = 0.44, 95% CI = 0.24-0.80) with low heterogeneity (I2  = 12.3%, P = 0.337), but not in North America (RR = 1.58, I2  = 89.5%, P = < 0.001). Combined OST/NSP is associated with a 74% reduction in HCV acquisition risk (RR = 0.26, 95% CI = 0.07-0.89, I2  = 80% P = 0.007). According to Grades of Recommendation Assessment, Development and Evaluation (GRADE) criteria, the evidence on OST and combined OST/NSP is low quality, while NSP is very low.

CONCLUSIONS

Opioid substitution therapy reduces risk of hepatitis C acquisition and is strengthened in combination with needle and syringe programmes (NSP). There is weaker evidence for the impact of needle syringe programmes alone, although stronger evidence that high coverage is associated with reduced risk in Europe.

Direct-acting antiviral agents for HCV infection affecting people who inject drugs

Globally, 12 million people are estimated to have injected drugs in the past year, 50% of whom have chronic HCV infection, with people who have previously injected drugs presenting an additional large reservoir of infection. The availability of simple and tolerable interferon-free direct-acting antiviral agents (DAAs) for HCV infection, which have a cure rate of >95% represents one of the most exciting advances in clinical medicine in the past few decades. Adherence and response to DAA therapy among people who inject drugs (PWID) receiving opioid substitution therapy (OST) in clinical trials are comparable to populations without a history of injecting drugs. Further data are required among current PWID not receiving OST. Given the potential prevention benefits of treatment, DAAs have enhanced cost-effectiveness among PWID. As HCV therapy is expanded to populations of PWID with high-risk behaviours for re-exposure, acknowledgement that HCV reinfection will occur is crucial, and appropriate strategies must be in place to maximize prevention of reinfection and offer retreatment for reinfection. This Review will also discuss essential components for broadening access to HCV care for PWID as we strive for the global elimination of HCV infection.

Cessation of Injecting and Preceding Drug Use Patterns Among a Prospective Cohort of Street-Involved Youth

PURPOSE

Injection drug use is prevalent among street-involved youth, but patterns of cessation are poorly described. We identified drug use patterns preceding injection cessation among street-involved youth.

METHODS

From September 2005 to May 2015, we collected data from the At-Risk Youth Study, a prospective cohort of street-involved youth in Vancouver, Canada, and limited the sample to actively injecting youth. The primary outcome was cessation of injecting self-reported at semiannual follow-up visits. We used Cox regression to identify drug use patterns preceding cessation.

RESULTS

Among 383 youth, 65% were male, mean age was 22.3 (standard deviation, 2.5; range, 15-30) years, and 171 (45%) ceased injecting for 6 months or more (crude incidence density 22 per 100 person-years; 95% confidence interval [CI], 19-26). Youth who ceased were less likely to have injected daily (adjusted hazard ratio [AHR], .40; 95% CI, .28-.56), injected heroin (AHR, .40; 95% CI, .29-.56), or injected crystal methamphetamine (AHR, .43; 95% CI, .31-.59) before cessation. Noninjection heroin use was positively associated with injection cessation (AHR, 1.52; 95 CI, 1.12-2.08). Addiction treatment was not associated with cessation. At the time of cessation, 101 (59%) youth continued to use "hard" noninjection drugs such as heroin and crystal methamphetamine.

CONCLUSIONS

Periods of injection cessation were common but frequently accompanied by ongoing noninjection drug use. Findings indicate that trajectories of injection drug use among youth are complex and highlight the need to further explore relationships between ongoing noninjection drug use and injection cessation.

Needle syringe programmes and opioid substitution therapy for preventing hepatitis C transmission in people who inject drugs

BACKGROUND

Needle syringe programmes and opioid substitution therapy for preventing hepatitis C transmission in people who inject drugsNeedle syringe programmes (NSP) and opioid substitution therapy (OST) are the primary interventions to reduce hepatitis C (HCV) transmission in people who inject drugs. There is good evidence for the effectiveness of NSP and OST in reducing injecting risk behaviour and increasing evidence for the effectiveness of OST and NSP in reducing HIV acquisition risk, but the evidence on the effectiveness of NSP and OST for preventing HCV acquisition is weak.

OBJECTIVES

To assess the effects of needle syringe programmes and opioid substitution therapy, alone or in combination, for preventing acquisition of HCV in people who inject drugs.

SEARCH METHODS

We searched the Cochrane Drug and Alcohol Register, CENTRAL, the Cochrane Database of Systematic Reviews (CDSR), the Database of Abstracts of Reviews of Effects (DARE), the Health Technology Assessment Database (HTA), the NHS Economic Evaluation Database (NHSEED), MEDLINE, Embase, PsycINFO, Global Health, CINAHL, and the Web of Science up to 16 November 2015. We updated this search in March 2017, but we have not incorporated these results into the review yet. Where observational studies did not report any outcome measure, we asked authors to provide unpublished data. We searched publications of key international agencies and conference abstracts. We reviewed reference lists of all included articles and topic-related systematic reviews for eligible papers.

SELECTION CRITERIA

We included prospective and retrospective cohort studies, cross-sectional surveys, case-control studies and randomised controlled trials that measured exposure to NSP and/or OST against no intervention or a reduced exposure and reported HCV incidence as an outcome in people who inject drugs. We defined interventions as current OST (within previous 6 months), lifetime use of OST and high NSP coverage (regular attendance at an NSP or all injections covered by a new needle/syringe) or low NSP coverage (irregular attendance at an NSP or less than 100% of injections covered by a new needle/syringe) compared with no intervention or reduced exposure.

DATA COLLECTION AND ANALYSIS

We followed the standard Cochrane methodological procedures incorporating new methods for classifying risk of bias for observational studies. We described study methods against the following 'Risk of bias' domains: confounding, selection bias, measurement of interventions, departures from intervention, missing data, measurement of outcomes, selection of reported results; and we assigned a judgment (low, moderate, serious, critical, unclear) for each criterion.

MAIN RESULTS

We identified 28 studies (21 published, 7 unpublished): 13 from North America, 5 from the UK, 4 from continental Europe, 5 from Australia and 1 from China, comprising 1817 incident HCV infections and 8806.95 person-years of follow-up. HCV incidence ranged from 0.09 cases to 42 cases per 100 person-years across the studies. We judged only two studies to be at moderate overall risk of bias, while 17 were at serious risk and 7 were at critical risk; for two unpublished datasets there was insufficient information to assess bias. As none of the intervention effects were generated from RCT evidence, we typically categorised quality as low. We found evidence that current OST reduces the risk of HCV acquisition by 50% (risk ratio (RR) 0.50, 95% confidence interval (CI) 0.40 to 0.63, I2 = 0%, 12 studies across all regions, N = 6361), but the quality of the evidence was low. The intervention effect remained significant in sensitivity analyses that excluded unpublished datasets and papers judged to be at critical risk of bias. We found evidence of differential impact by proportion of female participants in the sample, but not geographical region of study, the main drug used, or history of homelessness or imprisonment among study samples.Overall, we found very low-quality evidence that high NSP coverage did not reduce risk of HCV acquisition (RR 0.79, 95% CI 0.39 to 1.61) with high heterogeneity (I2 = 77%) based on five studies from North America and Europe involving 3530 participants. After stratification by region, high NSP coverage in Europe was associated with a 76% reduction in HCV acquisition risk (RR 0.24, 95% CI 0.09 to 0.62) with less heterogeneity (I2 =0%). We found low-quality evidence of the impact of combined high coverage of NSP and OST, from three studies involving 3241 participants, resulting in a 74% reduction in the risk of HCV acquisition (RR 0.26 95% CI 0.07 to 0.89).

AUTHORS' CONCLUSIONS

OST is associated with a reduction in the risk of HCV acquisition, which is strengthened in studies that assess the combination of OST and NSP. There was greater heterogeneity between studies and weaker evidence for the impact of NSP on HCV acquisition. High NSP coverage was associated with a reduction in the risk of HCV acquisition in studies in Europe.

Research priorities to achieve universal access to hepatitis C prevention, management and direct-acting antiviral treatment among people who inject drugs

Globally, it is estimated that 71.1 million people have chronic hepatitis C virus (HCV) infection, including an estimated 7.5 million people who have recently injected drugs (PWID). There is an additional large, but unquantified, burden among those PWID who have ceased injecting. The incidence of HCV infection among current PWID also remains high in many settings. Morbidity and mortality due to liver disease among PWID with HCV infection continues to increase, despite the advent of well-tolerated, simple interferon-free direct-acting antiviral (DAA) HCV regimens with cure rates >95%. As a result of this important clinical breakthrough, there is potential to reverse the rising burden of advanced liver disease with increased treatment and strive for HCV elimination among PWID. Unfortunately, there are many gaps in knowledge that represent barriers to effective prevention and management of HCV among PWID. The Kirby Institute, UNSW Sydney and the International Network on Hepatitis in Substance Users (INHSU) established an expert round table panel to assess current research gaps and establish future research priorities for the prevention and management of HCV among PWID. This round table consisted of a one-day workshop held on 6 September, 2016, in Oslo, Norway, prior to the International Symposium on Hepatitis in Substance Users (INHSU 2016). International experts in drug and alcohol, infectious diseases, and hepatology were brought together to discuss the available scientific evidence, gaps in research, and develop research priorities. Topics for discussion included the epidemiology of injecting drug use, HCV, and HIV among PWID, HCV prevention, HCV testing, linkage to HCV care and treatment, DAA treatment for HCV infection, and reinfection following successful treatment. This paper highlights the outcomes of the roundtable discussion focused on future research priorities for enhancing HCV prevention, testing, linkage to care and DAA treatment for PWID as we strive for global elimination of HCV infection.

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.

Elimination of HCV as a public health concern among people who inject drugs by 2030 - What will it take to get there?

INTRODUCTION

Globally, there is a considerable burden of HCV and HIV infections among people who inject drugs (PWID) and transmission of both infections continues. Needle and syringe programme (NSP) and opioid substitution therapy (OST) coverage remains low, despite evidence demonstrating their prevention benefit. Direct-acting antiviral therapies (DAA) with HCV cure >95% among PWID provide an opportunity to reverse rising trends in HCV-related morbidity and mortality and reduce incidence. However, HCV testing, linkage to care, and treatment remain low due to health system, provider, societal, and patient barriers. Between 2015 and 2030, WHO targets include reducing new HCV infections by 80% and HCV deaths by 65%, and increasing HCV diagnoses from <5% to 90% and number of eligible persons receiving HCV treatment from <1% to 80%. This commentary discusses why PWID should be considered as a priority population in these efforts, reasons why this goal could be attainable among PWID, challenges that need to be overcome, and key recommendations for action.

DISCUSSION

Challenges to HCV elimination as a global health concern among PWID include poor global coverage of harm reduction services, restrictive drug policies and criminalization of drug use, poor access to health services, low HCV testing, linkage to care and treatment, restrictions for accessing DAA therapy, and the lack of national strategies and government investment to support WHO elimination goals. Key recommendations for action include reforming drug policies (decriminalization of drug use and/or possession, or providing alternatives to imprisonment for PWID; decriminalization of the use and provision of sterile needles-syringes; and legalization of OST for people who are opioid dependent), scaling up and improving funding for harm reduction services, making health services accessible for PWID, supporting community empowerment and community-based programmes, improving access to affordable diagnostics and medicines, and eliminating stigma, discrimination, and violence against PWID.

CONCLUSIONS

The ambitious targets for HCV elimination set by WHO are achievable in many countries, but will require researchers, healthcare providers, policy makers, affected communities, advocates, the pharmaceutical and diagnostics industries, and governments around the world to work together to make this happen.

High hepatitis C incidence in relation to prescription opioid injection and poly-drug use: Assessing barriers to hepatitis C prevention

BACKGROUND

Prescription opioid (PO) injection and poly-drug use have been associated with hepatitis C virus (HCV) infection among people who inject drugs (PWID). Poly-drug use is often a barrier to key HCV preventive programmes including opioid agonist treatment. The contribution of specific drug combinations to high HCV incidence in poly-drug users has not been assessed previously. Addressing this knowledge gap could enhance HCV treatment and prevention efforts. We examined the association between specific drugs and number of drugs used in addition to injected POs, and HCV seroconversion.

METHODS

PWID participating in a cohort study in Montréal (HEPCO), HCV-seronegative at baseline and followed between 2004 and 2013, were included. Data were collected by interview-administered questionnaires. Blood samples were tested for HCV new infections at each 3-6 month follow-up visit. Time-varying Cox regression models were utilized.

RESULTS

Of 356 participants (81.5% males; mean age: 34.7 years), 123 (34.6%) reported injected POs in the past month at baseline. In univariate analyses, recent use of the following drugs was associated with HCV seroconversion: injected POs, injected cocaine, injected heroin, non-injected tranquilisers, and smoked crack/cocaine. The relative excess risk of HCV seroconversion due to interaction (RER1_HR) was the highest for co-use of injected POs with the following substances: injected cocaine (RER1_HR=3.44), smoked crack/cocaine (RER1_HR=1.27), and non-injected tranquilisers (RER1_HR=0.8). In addition, a significant linear trend (p<0.001) towards higher risk was observed with increasing the number of these three drugs used in combination with injected POs.

CONCLUSION

Specific drugs and number of drugs used in addition to injected POs play a modulating role in the risk of HCV primary infection. Poly-drug use among people who inject POs has to be addressed in order to improve harm reduction programmes and reduce HCV transmission in this high-risk population.

Medical and Behavioral Approaches to Engage People Who Inject Drugs Into Care for Hepatitis C Virus Infection

Direct-acting antivirals for hepatitis C virus infection may revolutionize treatment among persons with substance use disorders. Despite persons with substance use disorders having the highest hepatitis C virus prevalence and incidence, the vast majority have not engaged into care for the infection. Previously, interferon-based treatments, with substantial side effects and the propensity to exacerbate mental health conditions, were major disincentives to pursuit of care for the infection. Direct-acting antivirals with viral eradication rates of >90%, significantly improved side effect profiles, and shorter treatment duration are dramatic improvements over prior treatment regimens that should promote widespread hepatitis C virus care among persons with substance use disorders. The major unmet need is strategies to promote persons with substance use disorders engagement into care for hepatitis C virus. Although physical integration of treatment for substance use and co-occurring conditions has been widely advocated, it has been difficult to achieve. Telemedicine offers an opportunity for virtual integration of behavioral and medical treatments that could be supplemented by conventional interventions such as hepatitis C virus education, case management, and peer navigation. Furthermore, harm reduction and strategies to reduce viral transmission are important to cease reinfection among persons with substance use disorders. Widespread prescription of therapy for hepatitis C virus infection to substance users will be required to achieve the ultimate goal of global virus elimination. Combinations of medical and behavioral interventions should be used to promote persons with substance use disorders engagement into and adherence with direct-acting antiviral-based treatment approaches. Ultimately, either physical or virtual colocation of hepatitis C virus and substance use treatment has the potential to improve adherence and consequently treatment efficacy.

The need for treatment scale-up to impact HCV transmission in people who inject drugs in Montréal, Canada: a modelling study

Background

HCV transmission remains high in people who inject drugs (PWID) in Montréal. New direct-acting antivirals (DAAs), highly effective and more tolerable than previous regimens, make a “Treatment as Prevention” (TasP) strategy more feasible. This study assesses how improvements in the cascade of care could impact hepatitis C burden among PWID in Montréal.

Methods

We used a dynamic model to simulate HCV incidence and prevalence after 10 years, and cirrhosis complications after 10 and 40 years. Eight scenarios of improved cascade of care were examined.

Results

Using a baseline incidence and prevalence of 22.1/100 person-years (PY) and 53.1%, implementing the current cascade of care using DAAs would lead to HCV incidence and prevalence estimates at 10 years of 9.4/100PY and 55.8%, respectively. Increasing the treatment initiation rate from 5%/year initially to 20%/year resulted in large decreases in incidence (6.4/100PY), prevalence (36.6%), and cirrhosis complications (−18%/-37% after 10/40 years). When restricting treatment to fibrosis level ≥ F2 instead of F0 (reference scenario), such decreases in HCV occurrence were unreachable. Improving the whole cascade of care led to the greatest effect by halving both the incidence and prevalence at 10 years, and the number of cirrhosis complications after 40 years.

Conclusions

The current level of treatment access in Montréal is limiting a massive decrease in hepatitis C burden among PWID. A substantial treatment scale-up, regardless of fibrosis level, is necessary. While improving the rest of the cascade of care is necessary to optimize a TasP strategy and control the HCV epidemic, a treatment scale-up is first needed.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-017-2256-5) contains supplementary material, which is available to authorized users.

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.

Injection drug use among children and adolescents in India: Ringing the alarm bells

INTRODUCTION

Injection drug use (IDU) is intricately linked to preventive aspects for human immunodeficiency virus from a public health perspective. No large-scale data are yet available for injectable drug use among children and adolescents in India, apart from few anecdotal reports.

AIMS AND METHODS

The present paper reports on the profile and substance use pattern of 509 child IDU users, among a total sample of over 4000 children using substances across 100 sites from 27 states and 2 UTs in India. It was undertaken in 2012-2013 by the National Commission of Protection for Child Rights in collaboration with the National Drug Dependence Treatment Centre, All India Institute of Medical Sciences, New Delhi. For inclusion, participants had to be 18 years or less, should have used at least one other substance besides tobacco in the last 1 year, and should be living at home/street, in or out of school. Data were gathered using a 95-item semi-structured questionnaire.

RESULTS

A large proportion of ever users of IDU also reported use in the past year (96.5%) and past month (92.7%). Apart from IDU, tobacco, alcohol, cannabis, and pharmaceutical opioids were the most common substances of abuse in order of frequency. There was an interval of about 3 years from the initiation of tobacco to the initiation of IDU. Average age of onset for IDU was a year lesser in males than female users. The street children initiated IDU earlier than out-of-school and schoolgoing children. No quit attempt was made by more than half of the children. More than 40% had frequent familial conflicts, more than half had a familial history of substance use, and three-fourths had drug-using peers.

CONCLUSION

The paper highlights the profile and pattern of children and adolescents using IDU across many parts of India, dispelling the myth that IDU is largely an adult phenomenon in India. There is a clear need to promote different harm reduction and preventive strategies across the "hard-to-reach" younger age groups using injecting drugs.

Estimating the Impact of Expanding Treatment Coverage and Allocation Strategies for Chronic Hepatitis C in a Direct Antiviral Agent Era

Hepatitis C virus (HCV) infection is an important worldwide public health problem, and most of the global HCV burden is in low- to middle-income countries. This study aimed to estimate the future burden of chronic hepatitis C (CHC) and the impact of public health policies using novel antiviral agents in Thailand. A mathematical model of CHC transmission dynamics was constructed to examine the disease burden over the next 20 years using different treatment strategies. We compared and evaluated the current treatment (PEGylated interferon and ribavirin) with new treatments using novel direct-acting antiviral agents among various treatment policies. Thailand’s CHC prevalence was estimated to decrease 1.09%–0.19% in 2015–2035. Expanding treatment coverage (i.e., a five-fold increment in treatment accessibility) was estimated to decrease cumulative deaths (33,007 deaths avoided, 25.5% reduction) from CHC-related decompensated cirrhosis and hepatocellular carcinoma (HCC). The yearly incidence of HCC-associated HCV was estimated to decrease from 2,305 to 1,877 cases yearly with expanding treatment coverage. A generalized treatment scenario (i.e., an equal proportional distribution of available treatment to individuals at all disease stages according to the number of cases at each stage) was predicted to further reduce death from HCC (9,170 deaths avoided, 11.3% reduction) and the annual incidence of HCC (i.e., a further decrease from 1,877 to 1,168 cases yearly, 37.7% reduction), but cumulative deaths were predicted to increase (by 3,626 deaths, 3.7% increase). Based on the extensive coverage scenario and the generalized treatment scenario, we estimated near-zero death from decompensated cirrhosis in 2031. In conclusion, CHC-related morbidity and mortality in Thailand are estimated to decrease dramatically over the next 20 years. Treatment coverage and allocation strategies are important factors that affect the future burden of CHC in resource-limited countries like Thailand.

Risk Factors Associated with Unsafe Injection Practices at the First Injection Episode among Intravenous Drug Users in France: Results from PrimInject, an Internet Survey

Background. New drug use patterns may increase the risk of human immunodeficiency virus and hepatitis infections. In France, new injection patterns among youths with diverse social backgrounds have emerged, which may explain the persistently high rates of hepatitis C virus infection. This study explores factors associated with injection risk behaviours at first injection among users who began injecting in the post-2000 era. Methods. A cross-sectional study was conducted on the Internet from October 2010 to March 2011, through an online questionnaire. Multivariate logistic regression identified the independent correlates of needle sharing and equipment (cooker/cotton filter) sharing. Results. Among the 262 respondents (mean age 25 years), 65% were male. Both risk behaviours were positively associated with initiation before 18 years of age (aOR 3.7 CI 95% 1.3–10.6 and aOR 3.0 CI 95% 1.3–7.0) and being injected by another person (aOR 3.1 CI 95% 1.0–9.9 and aOR 3.0 CI 95% 1.3–7.1). Initiation at a party was an independent correlate of equipment sharing (aOR 2.6 95% CI 1.0–6.8). Conclusions. Results suggest a need for innovative harm reduction programmes targeting a variety of settings and populations, including youths and diverse party scenes. Education of current injectors to protect both themselves and those they might initiate into injection is critically important.

Visits to primary care physicians among persons who inject drugs at high risk of hepatitis C virus infection: room for improvement

The role of primary care physicians (PCP) in hepatitis C virus (HCV) prevention is increasingly emphasized. Yet, little is known about the patterns of contacts with PCP among persons who inject drugs (PWID). We sought to assess the 6-month prevalence of PCP visiting among PWID at risk of HCV infection and to explore the associated factors. Baseline data were collected from HCV-seronegative PWID recruited in HEPCO, an observational Hepatitis Cohort study (2004-2011) in Montreal, Canada. An interviewer-administered questionnaire elicited information on socio-demographic factors, drug use patterns and healthcare services utilization. Blood samples were tested for HCV antibodies. Using the Gelberg-Andersen Behavioral Model, hierarchical logistic regression analyses were conducted to identify predisposing, need and enabling factors associated with PCP visiting. Of the 349 participants (mean age = 34; 80.8% male), 32.1% reported visiting a PCP. In the multivariate model, among predisposing factors, male gender [adjusted odds ratio (AOR) = 0.45 (0.25-0.83)], chronic homelessness [AOR = 0.08 (0.01-0.67)], cocaine injection [AOR = 0.46 (0.28-0.76)] and reporting greater illegal or semi-legal income [AOR = 0.48 (0.27-0.85)] were negatively associated with PCP visits. Markers of need were not associated with the outcome. Among enabling factors, contact with street nurses [AOR = 3.86 (1.49-9.90)] and food banks [AOR = 2.01 (1.20-3.37)] was positively associated with PCP visiting. Only one third of participating PWID reported a recent visit to a PCP. While a host of predisposing factors seems to hamper timely contacts with PCP among high-risk PWID, community-based support services may play an important role in initiating dialogue with primary healthcare services in this population.

Recommendations for the management of hepatitis C virus infection among people who inject drugs

In high income countries, the majority of new and existing hepatitis C virus (HCV) infections occur among people who inject drugs (PWID). In many low and middle income countries large HCV epidemics have also emerged among PWID populations. The burden of HCV-related liver disease among PWID is increasing, but treatment uptake remains extremely low. There are a number of barriers to care which should be considered and systematically addressed, but should not exclude PWID from HCV treatment. The rapid development of interferon-free direct-acting antiviral (DAA) therapy for HCV infection has brought considerable optimism to the HCV sector, with the realistic hope that therapeutic intervention will soon provide near optimal efficacy with well-tolerated, short duration, all oral regimens. Further, it has been clearly demonstrated that HCV treatment is safe and effective across a broad range of multidisciplinary healthcare settings. Given the burden of HCV-related disease among PWID, strategies to enhance HCV assessment and treatment in this group are urgently needed. These recommendations demonstrate that treatment among PWID is feasible and provide a framework for HCV assessment and care. Further research is needed to evaluate strategies to enhance testing, linkage to care, treatment, adherence, viral cure, and prevent HCV reinfection among PWID, particularly as new interferon-free DAA treatments for HCV infection become available.

Methamphetamine injecting is associated with phylogenetic clustering of hepatitis C virus infection among street-involved youth in Vancouver, Canada

BACKGROUND

Among prospective cohorts of people who inject drugs (PWID), phylogenetic clustering of HCV infection has been observed. However, the majority of studies have included older PWID, representing distant transmission events. The aim of this study was to investigate phylogenetic clustering of HCV infection among a cohort of street-involved youth.

METHODS

Data were derived from a prospective cohort of street-involved youth aged 14-26 recruited between 2005 and 2012 in Vancouver, Canada (At Risk Youth Study, ARYS). HCV RNA testing and sequencing (Core-E2) were performed on HCV positive participants. Phylogenetic trees were inferred using maximum likelihood methods and clusters were identified using ClusterPicker (Core-E2 without HVR1, 90% bootstrap threshold, 0.05 genetic distance threshold).

RESULTS

Among 945 individuals enrolled in ARYS, 16% (n=149, 100% recent injectors) were HCV antibody positive at baseline interview (n=86) or seroconverted during follow-up (n=63). Among HCV antibody positive participants with available samples (n=131), 75% (n=98) had detectable HCV RNA and 66% (n=65, mean age 23, 58% with recent methamphetamine injection, 31% female, 3% HIV+) had available Core-E2 sequences. Of those with Core-E2 sequence, 14% (n=9) were in a cluster (one cluster of three) or pair (two pairs), with all reporting recent methamphetamine injection. Recent methamphetamine injection was associated with membership in a cluster or pair (P=0.009).

CONCLUSION

In this study of street-involved youth with HCV infection and recent injecting, 14% demonstrated phylogenetic clustering. Phylogenetic clustering was associated with recent methamphetamine injection, suggesting that methamphetamine drug injection may play an important role in networks of HCV transmission.

The impact of methadone maintenance therapy on hepatitis C incidence among illicit drug users

AIMS

To determine the relationship between methadone maintenance therapy (MMT) and hepatitis C (HCV) seroconversion among illicit drug users.

DESIGN

A generalized estimating equation model assuming a binomial distribution and a logit-link function was used to examine for a possible protective effect of MMT use on HCV incidence.

SETTING

Data from three prospective cohort studies of illicit drug users in Vancouver, Canada between 1996 and 2012.

PARTICIPANTS

A total of 1004 HCV antibody-negative illicit drug users stratified by exposure to MMT.

MEASUREMENTS

Baseline and semi-annual HCV antibody testing and standardized interviewer-administered questionnaire soliciting self-reported data relating to drug use patterns, risk behaviors, detailed socio-demographic data and status of active participation in an MMT program.

FINDINGS

One hundred and eighty-four HCV seroconversions were observed for an HCV incidence density of 6.32 [95% confidence interval (CI) = 5.44-7.31] per 100 person-years. After adjusting for potential confounders, MMT exposure was protective against HCV seroconversion [adjusted odds ratio (AOR) = 0.47; 95% CI = 0.29-0.76]. In subanalyses, a dose-response protective effect of increasing MMT exposure on HCV incidence (AOR = 0.87; 95% CI = 0.78-0.97) per increasing 6-month period exposed to MMT was observed.

CONCLUSION

Participation in methadone maintenance treatment appears to be highly protective against hepatitis C incidence among illicit drug users. There appears to be a dose-response protective effect of increasing methadone exposure on hepatitis C incidence.

Risk factors for HCV infection among young adults in rural New York who inject prescription opioid analgesics

OBJECTIVES

We investigated a cluster of new hepatitis C cases in rural New York among a cohort of young people who inject drugs (PWID) and misuse prescription opioid analgesics (POA).

METHODS

We recruited a purposive sample of PWID from Cortland County for an in-person survey and HCV rapid antibody test (March-July 2012). We examined sociodemographics, drugs currently injected, and lifetime and recent injection behaviors to ascertain associations with HCV antibody (anti-HCV) positivity.

RESULTS

Of 123 PWID, 76 (61.8%) were younger than 30 years, and 100 (81.3%) received HCV rapid testing. Of those tested, 34 (34.0%) were positive. Participants who reported injecting POA in the past 12 months were 5 times more likely to be anti-HCV positive than those who injected drugs other than POA, and participants who reported sharing injection equipment in the past 12 months were roughly 4 times more likely to be anti-HCV positive than those who did not.

CONCLUSIONS

Our analysis suggests people injecting POA may be at higher risk for HCV infection than people who inject heroin or other drugs but not POA.

Declining incidence of hepatitis C virus infection among people who inject drugs in a Canadian setting, 1996-2012

BACKGROUND

People who inject drugs (PWID) are at high risk of hepatitis C virus (HCV) infection. Trends in HCV incidence and associated risk factors among PWID recruited between 1996 and 2012 in Vancouver, Canada were evaluated.

METHODS

Data were derived from a long-term cohort of PWID in Vancouver. Trends in HCV incidence were evaluated. Factors associated with time to HCV infection were assessed using Cox proportional hazards regression.

RESULTS

Among 2,589, 82% (n = 2,121) were HCV antibody-positive at enrollment. Among 364 HCV antibody-negative participants with recent (last 30 days) injecting at enrollment, 126 HCV seroconversions were observed [Overall HCV incidence density: 8.6 cases/100 person-years (py); 95% confidence interval (95% CI): 7.2, 10.1; HCV incidence density among those with injecting during follow-up: 11.5 cases/100 py; 95% CI 9.7, 13.6]. The overall HCV incidence density declined significantly from 25.0/100 py (95% CI: 20.2, 30.3) in 1996-99, as compared to 6.0/100 py (95% CI: 4.1, 8.5) in 2000-2005, and 3.1/100 py (95% CI: 2.0, 4.8) in 2006-2012. Among those with injecting during follow-up, the overall HCV incidence density declined significantly from 27.9/100 py (95% CI: 22.6, 33.6) in 1996-99, as compared to 7.5/100 py (95% CI: 5.1, 10.6) in 2000-2005, and 4.9/100 py (95% CI: 3.1, 7.4) in 2006-2012. Unstable housing, HIV infection, and injecting of cocaine, heroin and methamphetamine were independently associated with HCV seroconversion.

CONCLUSIONS

HCV incidence has dramatically declined among PWID in this setting. However, improved public health strategies to prevent and treat HCV are urgently required to reduce HCV-associated morbidity and mortality.

Interrupting the social processes linked with initiation of injection drug use: results from a pilot study

BACKGROUND

Injection drug use is a skill learned in social settings. Change the Cycle (CTC), a peer-delivered, one-session intervention, is designed to reduce among people who inject drugs (PIDs) injection initiation-related behaviours (i.e., speaking positively about injecting to non-injectors, injecting in front of non-injectors, explaining or showing a non-injector how to inject) and initiation of non-injectors. We hypothesized that participation in CTC would lead to reductions in initiation-related behaviours six months later.

METHODS

Using respondent driven sampling (RDS), 98 PIDs were recruited in Toronto, Canada to participate in pilot testing of CTC. The baseline session consisted of a structured interview, the peer-delivered CTC intervention, instructions regarding RDS coupon distribution, and an invitation to return in six months for a follow-up interview. For the 84 PIDs completing the six-month interview, we compared initiation-related behaviours at baseline with six-month follow-up.

RESULTS

The proportion of PIDs offering to initiate a non-injector was reduced from 8.4% (95% CI: 2.5, 15.9) at baseline to 1.59% (95% CI: 0.4, 3.7) at 6-month follow-up. The prevalence of speaking positively about injection to non-injectors also decreased significantly. The proportion of PIDs who helped a non-injector with a first injection at baseline was 6.2% (95% CI: 2.1, 11.3) and at follow-up was 3.5% (95% CI: 0.8, 7.1). Paired analyses of initiator baseline versus follow-up data showed a 72.7% reduction in initiation (95%CI: 47.7, 83.1).

CONCLUSIONS

While further refinements remain to be tested, pilot study results suggest that CTC holds promise as a prevention intervention.

Incidence of hepatitis C infection among prisoners by routine laboratory values during a 20-year period

BACKGROUND

To estimate the incidence of Hepatitis C virus (HCV) and the predictive factors through repeated routine laboratory analyses.

METHODS

An observational cohort study was carried out in Quatre Camins Prison, Barcelona. The study included subjects with an initial negative HCV result and routine laboratory analyses containing HCV serology from 1992 to 2011. The incidence of infection was calculated for the study population and for sub-groups by 100 person-years of follow-up (100 py). The predictive factors were determined through Kaplan-Meier curves and a Cox regression. Hazard ratios (HR) and 95% confidence intervals (CI) were calculated.

RESULTS

A total of 2,377 prisoners were included with a median follow-up time of 1,540.9 days per patient. Among the total population, 117 HCV seroconversions were detected (incidence of 1.17/100 py). The incidence was higher between 1992 and 1995 (2.57/100 py), among cases with HIV co-infection (8.34/100 py) and among intravenous drug users (IDU) without methadone treatment (MT) during follow-up (6.66/100 py). The incidence rate of HCV seroconversion among cases with a history of IDU and current MT was 1.35/100 py, which is close to that of the total study population. The following variables had a positive predictive value for HCV infection: IDU (p<0.001; HR = 7,30; CI: 4.83-11.04), Spanish ethnicity (p = 0.009; HR = 2,03; CI: 1.93-3.44) and HIV infection (p = 0.015; HR = 1.97; CI: 1.14-3.39).

CONCLUSION

The incidence of HCV infection among prisoners was higher during the first part of the study and among IDU during the entire study period. Preventative programs should be directed toward this sub-group of the prison population.

Changing patterns of first injection across key periods of the French Harm Reduction Policy: PrimInject, a cross sectional analysis

BACKGROUND

Monitoring of emerging modes of drug consumption in France has identified new patterns of injection among youths with diverse social backgrounds, which may explain the persistence of high rates of hepatitis C virus infection. The circumstances surrounding the first injection have been poorly documented in the group of heavy drug users and in the context of the French opioid substitution treatment (OST) policy that provides expanded access to high-dosage buprenorphine (BHD) METHODS: An Internet survey (Priminject) was conducted from October 2010 to March 2011 with French drug users. Four time periods were compared based on critical dates throughout the implementation of the Harm Reduction Policy in France.

RESULTS

Compared with drug users who injected for the first time prior to 1995, the aspects of drug use for users who recently injected for the first time were as follows: (1) experimentation with miscellaneous drugs before the first injection; (2) an older age at the time of first injection; (3) heroin as the drug of choice for an individual's first injection, notwithstanding the increased usage of stimulant drugs; (4) BHD did not appear to be a pathway to injection; and (5) an increased number of users who injected their first time alone, without the help or presence of another individual.

CONCLUSION

The PrimInject study showed that there is a group of injection drug users that is larger than the group of injection drug users observed in previous studies; therefore, it is necessary to diversify programs to reach the entire spectrum of high-risk users.

Diagnosis and treatment of acute hepatitis C virus infection

The first 6 months after exposure to hepatitis C virus (HCV) are regarded as acute hepatitis C (AHC). Two patient populations worldwide share the highest prevalence of AHC virus infection: injection drug users and HIV-positive men who have sex with men. Diagnosis of AHC is often difficult in both patient populations as the acute inflammatory phase can be clinically asymptomatic and patients at highest risk for acquiring AHC (injection drug users) tend to evade regular medical care. This article addresses similarities and differences in the epidemiology, diagnosis, and management of AHC monoinfection and coinfection.

Analysis of duration of risk behaviour for key populations: a literature review

Background

The objective of this paper is to review literature in order to calculate regional estimates of the average duration of time individuals maintain a specific high-risk behaviour.

Methods

The review targeted the key populations of female sex workers (FSW), male clients of female sex workers (MCFSW), people who inject drugs (injecting drug users (IDU)) and high-risk men who have sex with men (MSM). To be included in the review the study had to provide information on (1) the time a person spent at risk until death or cessation of the risk behaviour, (2) the percentage of the sample who initiated the risk behaviour in less than a year or (3) the mean or median duration of the behaviour from a representative sample.

Results

49 papers were found for the FSW population describing the period of time FSW stay in sex work to be between 2.9 years (Asia) and 12 years (Latin America). Eight papers were found for MCFSW showing the duration of the risk behaviour in this category varying from 4.6 years in Africa to 32 years in Asia. 86 papers were reviewed for the population of IDU showing that the average time a person injects illegal drugs varies from 5.6 years (Africa) to 21 years (South America). No information was found for duration of high-risk behaviour among MSM; instead, the definitions found in the literature for high- and low-risk behaviour among MSM were described.

Conclusions

There is high variability of estimates of duration of high-risk behaviours at regional level. More research is needed to inform models and prevention programmes on the average duration of time individuals maintain a specific high-risk behaviour.

Case definitions for acute hepatitis C virus infection: a systematic review

BACKGROUND & AIMS

Case definitions for recent hepatitis C virus (HCV) infection vary considerably between studies. The aim of this systematic review was to characterize case definitions for recent HCV and explore the heterogeneity in studies performed to date.

METHODS

A systematic literature search of MEDLINE, SCOPUS, and ISI Web of Knowledge was performed covering all studies of recent HCV infection cited between January 2000 and June 2011. The criteria used by each study to define cases of recent HCV infection were extracted, structured, and analyzed.

RESULTS

Overall, 195 articles were included, with 87% (n=169) providing a clear case definition for recent HCV infection. The most frequently used individual criteria for defining a case included HCV antibody seroconversion (77%), alanine aminotransferase (ALT) elevation (68%), and HCV RNA detection (63%). In studies using HCV antibody seroconversion, the window period between the last negative and the first positive antibody test varied widely across studies (4 weeks to 4 years). Considerable diversity was also observed with respect to the ALT threshold used to characterize ALT elevations, ranging from 2 to 20 times the upper limit of normal. HCV antibody seroconversion was used as a single criterion in 41% of the studies, while all other studies used at least two criteria (range: 2-9). Epidemiology/surveillance studies mostly used a more sensitive case definition, whereas treatment studies, natural history studies, and diagnosis studies used more specific case definitions.

CONCLUSIONS

Marked heterogeneity in case definitions for recent HCV infection was observed. Although a single case definition for recent HCV is not warranted, a degree of standardization within specific study categories would enable improved cross-study comparison and more uniform evaluation of HCV prevention and management strategies.

Childhood sexual abuse and risk for initiating injection drug use: a prospective cohort study

OBJECTIVE

This study examined whether childhood sexual abuse predicts initiation of injection drug use in a prospective cohort of youth.

METHOD

From October 2005 to November 2010, data were collected from the At Risk Youth Study (ARYS), a prospective cohort study of street-involved youth in Vancouver, Canada. Inclusion criteria were age 14-26 years, no lifetime drug injection, and non-injection drug use in the month preceding enrollment. Participants were interviewed at baseline and semiannually thereafter. Cox regression was employed to identify risk factors for initiating injection.

RESULTS

Among 395 injection-naïve youth, 81 (20.5%) reported childhood sexual abuse. During a median follow-up of 15.9 months (total follow-up 606.6 person-years), 45 (11.4%) youth initiated injection drug use, resulting in an incidence density of 7.4 per 100 person-years. In univariate analyses, childhood sexual abuse was associated with increased risk of initiating injection (unadjusted hazard ratio [HR], 2.38; 95% confidence interval [CI], 1.29-4.38; p=0.006), an effect that persisted in multivariate analysis despite adjustment for gender, age, aboriginal ancestry and recent non-injection drug use (adjusted HR, 2.71; 95% CI, 1.42-5.20; p=0.003).

CONCLUSION

Childhood sexual abuse places drug users at risk for initiating injection. Addiction treatment programs should incorporate services for survivors of childhood maltreatment.

Injection of drug residue as a potential risk factor for HCV acquisition among Montréal young injection drug users

BACKGROUND

Preparing drugs or medications for injection may leave residues in containers and filters used by injection drug users (IDUs). Little is known about the specific practice of injecting someone else's drug residue as a possible route of HCV transmission.

METHODS

A prospective cohort study of street youth aged 14-23 years old was carried out between July 2001 and December 2005. For this analysis, youth who injected in the six months prior to interview were selected if they were HCV-negative and had completed at least one follow-up visit. Semi-annual visits involved completing an interviewer-administered questionnaire and providing a blood sample for HCV antibody testing. "Sharing behaviors" (any injection preparation behavior that could entail IDUs using injection equipment used by others) including injecting someone else's drug residue were assessed at each interview. Predictors of HCV seroconversion were identified using Cox proportional hazards regression analyses. Two multivariate models were built, one considering sharing behaviors only, and one with cocaine injection forced into it.

RESULTS

Of the 175 participants, 60% were male and their mean age was 20.7years old. In both models, residue injection was a predictor of HCV incidence, although with marginal statistical significance. The adjusted hazard ratio estimates were (2.15; 95% CI 0.99-4.67) and (2.11; 95% CI 0.97-4.62) respectively.

CONCLUSION

This epidemiological study underscores the role injection of drug residue may play in HCV transmission among IDUs. In the current context of the worldwide HCV epidemics, this question deserves further investigation.

Homeless youth's overwhelming health burden: A review of the literature

Homelessness has reached epidemic proportions in Canada. Canadian children and adolescents are the most vulnerable because youth comprise the fastest growing segment of the homeless population. A systematic literature review was undertaken using MEDLINE, Web of Science and the Homeless Hub (www.homelesshub.ca) to encompass the time frame from January 1990 to June 2009. The following terms were used as key words: 'homelessness', 'homeless youth', 'poverty', 'street youth' and 'runaway'. The present review identified an intersection among education deficits, social service insufficiencies, and poor mental and physical health in homeless youth. Health care delivery to homeless youth was often nonanticipatory, inconsistent and perceived as discriminatory. However, street youth were identified as requiring health care for pregnancy, mental health concerns, sexually transmitted illnesses, respiratory conditions, substance abuse and a myriad of other illnesses. Plenty of work is still required to reduce health inequalities and improve the daily living conditions of Canadian youth living in poverty.

The ongoing impacts of hepatitis c--a systematic narrative review of the literature

BACKGROUND

Many countries have developed, or are developing, national strategies aimed at reducing the harms associated with hepatitis C infection. Making these strategies relevant to the vast majority of those affected by hepatitis C requires a more complete understanding of the short and longer term impacts of infection. We used a systematic approach to scope the literature to determine what is currently known about the health and psychosocial impacts of hepatitis C along the trajectory from exposure to ongoing chronic infection, and to identify what knowledge gaps remain.

METHODS

PubMed, Current Contents and PsychINFO databases were searched for primary studies published in the ten years from 2000-2009 inclusive. Two searches were conducted for studies on hepatitis C in adult persons focusing on: outcomes over time (primarily cohort and other prospective designs); and the personal and psychosocial impacts of chronic infection. All retrieved studies were assessed for eligibility according to specific inclusion/exclusion criteria, data completeness and methodological coherence. Outcomes reported in 264 included studies were summarized, tabulated and synthesized.

RESULTS

Injecting drug use (IDU) was a major risk for transmission with seroconversion occurring relatively early in injecting careers. Persistent hepatitis C viraemia, increasing age and excessive alcohol consumption independently predicted disease progression. While interferon based therapies reduced quality of life during treatment, improvements on baseline quality of life was achieved post treatment--particularly when sustained viral response was achieved. Much of the negative social impact of chronic infection was due to the association of infection with IDU and inflated assessments of transmission risks. Perceived discrimination was commonly reported in health care settings, potentially impeding health care access. Perceptions of stigma and experiences of discrimination also had direct negative impacts on wellbeing and social functioning.

CONCLUSIONS

Hepatitis C and its management continue to have profound and ongoing impacts on health and social well being. Biomedical studies provided prospective information on clinical aspects of infection, while the broader social and psychological studies presented comprehensive information on seminal experiences (such as diagnosis and disclosure). Increasing the focus on combined methodological approaches could enhance understanding about the health and social impacts of hepatitis C along the life course.