Prevalence and incidence of hepatitis C virus infection among young adult injection drug users

Serious Bacterial Infections and Hepatitis C Virus Among People Who Inject Drugs: A Syndemic or Intertwined Epidemics?

Limited research has examined the possible synergistic interrelationships between serious bacterial infections (SBIs) of the heart (i.e., endocarditis), bone, spine, brain, or joints (e.g., osteomylelitis) and hepatitis C virus (HCV) infections. We examined whether syndemic interactions existed between SBI, HCV, and substance-use-related factors in rural communities, hypothesizing that injection-mediated risks elevated the likelihood for both SBIs and HCV infections, which could be exacerbated by synergistic biological-biological or biological and social interactions. We calculated the prevalence ratios (PRs) of past-year SBI associated with each risk factor in separate models. Effect modification among significant risk factors was assessed using multiplicative interaction. Among 1936 participants, 57% were male and 85% White, with a mean age of 36 years. Eighty-nine participants (5%) reported hospitalization for an SBI in the year prior to the survey. More than half tested HCV-antibody-positive (58%); 62 (5.6%) of the participants with a positive HCV antibody result reported past-year hospitalization with an SBI. Injection behaviors were correlated with other SBI risk factors, including multiple injections in the same injection event (MIPIE), injection equipment sharing, and fentanyl use. In adjusted models, MIPIE (PR: 1.79; 95% confidence interval [CI]: 1.03, 3.11) and fentanyl use (PR: 1.68; 95% CI: 1.04, 2.73) were significantly associated with past-year SBI. Our analyses pointed to co-occurring epidemics of SBI and HCV, related to the cumulative health effects of fentanyl use contributing to frequent injections and MIPIE. Both the SBI and HCV epidemics present public health challenges and merit tailored interventions.

First-line opioid agonist treatment as prevention against assisting others in initiating injection drug use: A longitudinal cohort study of people who inject drugs in Vancouver, Canada

Background

Among people who inject drugs, frequent injecting and experiencing withdrawal are associated with facilitating others' first injections. As these factors may reflect an underlying substance use disorder, we investigated whether first-line oral opioid agonist treatment (OAT; methadone or buprenorphine/naloxone) reduces the likelihood that people who inject drugs help others initiate injecting.

Methods

We used questionnaire data from semi-annual visits between December 2014-May 2018 on 334 people who inject drugs with frequent non-medical opioid use in Vancouver, Canada. We estimated the effect of current first-line OAT on subsequent injection initiation assistance provision (i.e., helped someone initiate injecting in the following six months) using inverse-probability-weighted estimation of repeated measures marginal structural models to reduce confounding and informative censoring by time-fixed and time-varying covariates.

Results

By follow-up visit, 54-64% of participants reported current first-line OAT whereas 3.4-6.9% provided subsequent injection initiation assistance. Per the primary weighted estimate (n = 1114 person-visits), participants currently on first-line OAT (versus no OAT) were 50% less likely, on average, to subsequently help someone initiate injecting (relative risk [RR]=0.50, 95% CI=0.23-1.11). First-line OAT was associated with reduced risk of subsequent injection initiation assistance provision in participants who, at baseline, injected opioids less than daily (RR=0.15, 95% CI=0.05-0.44) but not in those who injected opioids daily (RR=0.86, 95% CI=0.35-2.11).

Conclusions

First-line OAT seemingly reduces the short-term likelihood that people who inject drugs facilitate first injections. However, the extent of this potential effect remains uncertain due to imprecise estimation and observed heterogeneity by baseline opioid injecting frequency.

The influence of poly-drug use patterns on the association between opioid agonist treatment engagement and injecting initiation assistance

BACKGROUND

Evidence suggests people who inject drugs (PWID) prescribed opioid agonist treatment (OAT) are less likely to provide injection drug use (IDU) initiation assistance. We investigated the association between OAT engagement and providing IDU initiation assistance across poly-drug use practices in Vancouver, Canada.

METHODS

Preventing Injecting by Modifying Existing Responses (PRIMER) is a prospective study seeking to identify structural interventions that reduce IDU initiation. We employed data from linked cohorts of PWID in Vancouver and extended the findings of a latent profile analysis (LPA). Multivariable logistic regression models were performed separately for the six poly-drug use LPA classes. The outcome was recently assisting others in IDU initiation; the independent variable was recent OAT engagement.

RESULTS

Among participants (n = 1218), 85 (7.0%) reported recently providing injection initiation assistance. When adjusting for age and sex, OAT engagement among those who reported a combination of high-frequency heroin and methamphetamine IDU and low-to-moderate-frequency prescription opioid IDU and methamphetamine non-injection drug use (NIDU) was associated with lower odds of IDU initiation assistance provision (Adjusted Odds Ratio [AOR]: 0.18, 95% CI: 0.05-0.63, P = 0.008). Significant associations were not detected among other LPA classes.

CONCLUSIONS

Our findings extend evidence suggesting that OAT may provide a population-level protective effect on the incidence of IDU initiation and suggest that this effect may be specific among PWID who engage in high-frequency methamphetamine and opioid use. Future research should seek to longitudinally investigate potential causal pathways explaining the association between OAT and initiation assistance provision among PWID to develop tailored intervention efforts.

Gender and the first-time provision of injection initiation assistance among people who inject drugs across two distinct North American contexts: Tijuana, Mexico and Vancouver, Canada

INTRODUCTION

Injection drug use initiation is commonly facilitated by other people who inject drugs (PWID). We investigated how the gender of PWID influences their risk of providing initiation assistance to others across two distinct geo-cultural settings.

METHODS

Data were drawn from two prospective cohorts in Tijuana, Mexico and Vancouver, Canada which conducted semi-annual interviews within the PReventing Injecting by Modifying Existing Responses (PRIMER) study. Participants consisted of PWID who had reported never providing injection initiation assistance at baseline. We then conducted site-specific discrete-time survival analyses assessing the relationship between gender and other relevant covariates (e.g. age and past 6-month sex work) on the risk of the first reported instance of providing initiation assistance.

RESULTS

Of 1988 PWID (Tijuana: n = 596; Vancouver: n = 1392), 256 (43%) and 511 (36.7%) participants were women, and 42 (1.7%) and 78 (1.6%) reported recent injection initiation assistance across a median of three and two follow-up visits, respectively. Women had a lower risk of providing injection initiation assistance for the first time in Tijuana (adjusted hazard ratio = 0.52, 95% confidence interval 0.27-0.99), but not in Vancouver. Gendered pathways, like sex work, were associated with providing initiation assistance for the first time in Vancouver (adjusted hazard ratio = 1.97, 95% confidence interval 1.08-3.61).

DISCUSSION AND CONCLUSIONS

Women in Tijuana, but not Vancouver, were less likely to provide first-time initiation assistance among PWID. These results can inform gender- and site-specific prevention efforts aimed at reducing transitions into drug injecting across geographic contexts.

HIV Risk Among Urban and Suburban People Who Inject Drugs: Elevated Risk Among Fentanyl and Cocaine Injectors in Maryland

Drug overdose remains a leading cause of death in the US, with growing rates attributable to illicit fentanyl use. Recent HIV outbreaks among people who inject drugs (PWID) and service disruptions from COVID-19 have renewed concerns on HIV resurgence. We examined the relationship between fentanyl use and three injection-related HIV risk behaviors among PWID in Baltimore City (BC) and Anne Arundel Country (AAC), Maryland. PWID (N = 283) were recruited to the study through targeted sampling at street-based locations in BC and AAC from July 2018 to March 2020. Receptive syringe sharing (RSS) [adjusted odds ratio (AOR): 2.8, 95% confidence interval (CI): 1.2–6.3] and daily injecting (AOR: 1.9, 95% CI: 1.0–3.6) were associated with injecting fentanyl and cocaine together. Fentanyl availability and COVID-19 bring new HIV prevention challenges, particularly among those who inject fentanyl with cocaine, highlighting the importance to expand and sustain harm reduction, prevention, and treatment services for PWID to reduce HIV and overdose burden.

Involvement of people who inject drugs in injection initiation events: a cross-sectional analysis identifying similarities and differences across three North American settings

OBJECTIVES

People who inject drugs (PWID) play an integral role in facilitating the entry of others into injection drug use (IDU). We sought to assess factors influencing PWID in providing IDU initiation assistance across three distinct North American settings and to generate pooled measures of risk.

DESIGN

We employed data from three PWID cohort studies participating in PReventing Injecting by Modifying Existing Responses (PRIMER), for this cross-sectional analysis.

SETTING

Tijuana, Mexico; San Diego, USA; Vancouver, Canada.

PARTICIPANTS

A total of 2944 participants were included in this study (Tijuana: n=766, San Diego: n=353, Vancouver: n=1825).

MEASUREMENTS

The outcome was defined as recently (ie, past 6 months) assisting in an IDU initiation event. Independent variables of interest were identified from previous PRIMER analyses. Site-specific multiple modified Poisson regressions were fit. Pooled relative risks (pRR) were calculated and heterogeneity across sites was assessed via linear random effects models.

RESULTS

Evidence across all three sites indicated that having a history of providing IDU initiation assistance (pRR: 4.83, 95% CI: 3.49 to 6.66) and recently being stopped by law enforcement (pRR: 1.49, 95% CI: 1.07 to 2.07) were associated with a higher risk of providing assistance with IDU initiation; while recent opioid agonist treatment (OAT) enrolment (pRR: 0.64, 95% CI: 0.43 to 0.96) and no recent IDU (pRR: 0.21, 95% CI: 0.07 to 0.64) were associated with a lower risk. We identified substantial differences across site in the association of age (I²: 52%), recent housing insecurity (I²: 39%) and recent non-injection heroin use (I²: 78%).

CONCLUSION

We identified common and site-specific factors related to PWID's risk of assisting in IDU initiation events. Individuals reporting a history of assisting IDU initiations, being recently stopped by law enforcement, and recently injecting methamphetamine/speedball were more likely to have recently assisted an IDU initiation. Whereas those who reported not recently engaging in IDU and those recently enrolled in OAT were less likely to have done so. Interventions and harm reduction strategies aimed at reducing the harms of IDU should incorporate context-specific approaches to reduce the initiation of IDU.

Examining the gender composition of drug injecting initiation events: A mixed methods investigation of three North American contexts

BACKGROUND

Gender influences the health and social risks faced by individuals initiating drug injecting. Using mixed methods across three settings in North America, we investigated the gender composition of injection initiation events and the gendered risk environments in which they occurred.

METHODS

The PReventing Injecting by Modifying Existing Responses (PRIMER) study pooled data from three prospective community-recruited cohorts of people who inject drugs (PWID) in San Diego, USA, Vancouver, Canada, and Tijuana, Mexico. A qualitative subsample provided narrative data on their experiences of, and the contexts for, injection initiation events. Guided by Rhodes' risk environment framework, we examined the gender composition of initiation events stratified by city, and analyzed qualitative data using abductive thematic analyses.

RESULTS

Among 2,622 PWID (Tijuana: n = 531; San Diego: n = 352; Vancouver: n = 1,739), 112 (4.3%) reported providing initiation assistance to injection-naïve individuals in the previous six months. The proportion of gender concordant (e.g., male-male) initiation pairs varied, (χ2 = 10.32, p <0.001) with greater than expected concordance among pairs in Tijuana compared with those in Vancouver or San Diego. Sixty-one interviews provided context for the discrepancy across sites by highlighting the gendered injection initiation risk environments of prison/jail detention in Tijuana, intimate partnerships in San Diego, and overdose risk in Vancouver.

CONCLUSIONS

These results highlight how gender influences injection initiation events within spatial, social, and economic risk environments, and how this influence varies across settings. These findings can inform interventions to reduce the risk of injection initiation and related harms.

'It's just basically a box full of disease'-navigating sterile syringe scarcity in a rural New England state

BACKGROUND AND AIMS

Injection drug use has increased in non-urban communities in the United States where sterile syringe access is limited. This study aimed to characterize how people who inject drugs in a predominantly rural state navigate syringe scarcity.

DESIGN

Qualitative study.

SETTING

New Hampshire (NH), USA. At the time of our study, syringe services programs were illegal in NH but pharmacies could sell ≤ 10 syringes without prescription.

PARTICIPANTS/CASES

Twenty people aged ≥ 18 years who injected at least once in the past 30 days were recruited through provider referral, street-based recruitment and snowball sampling.

MEASUREMENTS

Semi-structured interview guide. Verbatim transcripts were coded based on interview guide constructs and emergent themes. Analysis focused on pharmacy syringe access, unofficial syringe sources and related impacts on syringe sharing and reuse FINDINGS: Participants could identify no local pharmacies that sold syringes without prescription. Pharmacy purchase in neighboring counties, or across state lines, required private transportation and this, along with purchaser identification requirements, presented substantial access barriers. Interstate travel also exposed participants to vigilant policing of interstate highways and potential criminal justice involvement. Many participants thus resorted to informal syringe sources closer to home including purchasing syringes on the street, using discarded syringes, breaking into biohazard containers and constructing improvised syringes out of salvaged syringe parts, metals and plastics. Repeated re-use of syringes until they were no longer operational was common. Overall, syringe scarcity gave participants few options but to engage in syringe sharing and re-use, putting them at risk of serious injection-related infections.

CONCLUSIONS

Limited sterile syringe access contributes to an environment in which people who inject drugs report that they are less able to refrain from risky injection practices.

The role of drug treatment and recovery services: an opportunity to address injection initiation assistance in Tijuana, Mexico

BACKGROUND

In the U.S. and Canada, people who inject drugs' (PWID) enrollment in medication-assisted treatment (MAT) has been associated with a reduced likelihood that they will assist others in injection initiation events. We aimed to qualitatively explore PWID's experiences with MAT and other drug treatment and related recovery services in Tijuana Mexico, a resource-limited setting disproportionately impacted by injection drug use.

METHODS

PReventing Injecting by Modifying Existing Responses (PRIMER) seeks to assess socio-structural factors associated with PWID provision of injection initiation assistance. This analysis drew on qualitative data from Proyecto El Cuete (ECIV), a Tijuana-based PRIMER-linked cohort study. In-depth qualitative interviews were conducted with a subset of study participants to further explore experiences with MAT and other drug treatment services. Qualitative thematic analyses examined experiences with these services, including MAT enrollment, and related experiences with injection initiation assistance provision.

RESULTS

At PRIMER baseline, 607(81.1%) out of 748 participants reported recent daily IDU, 41(5.5%) reported recent injection initiation assistance, 92(12.3%) reported any recent drug treatment or recovery service access, and 21(2.8%) reported recent MAT enrollment (i.e., methadone). Qualitative analysis (n = 21; female = 8) revealed that, overall, abstinence-based recovery services did not meet participants' recovery goals, with substance use-related social connections in these contexts potentially shaping injection initiation assistance. Themes also highlighted individual-level (i.e., ambivalence and MAT-related stigma) and structural-level (i.e., cost and availability) barriers to MAT enrollment.

CONCLUSION

Tijuana's abstinence-based drug treatment and recovery services were viewed as unable to meet participants' recovery-related goals, which could be limiting the potential benefits of these services. Drug treatment and recovery services, including MAT, need to be modified to improve accessibility and benefits, like preventing transitions into drug injecting, for PWID.

Prevalence and Correlates of Providing and Receiving Assistance With the Transition to Injection Drug Use

Preventing the transition to injection drug use is an important public health goal, as people who inject drugs (PWID) are at high risk for overdose and acquisition of infectious disease. Initiation into drug injection is primarily a social process, often involving PWID assistance. A better understanding of the epidemiology of this phenomenon would inform interventions to prevent injection initiation and to enhance safety when assistance is provided. We conducted a systematic review of the literature to 1) characterize the prevalence of receiving (among injection-naive persons) and providing (among PWID) help or guidance with the first drug injection and 2) identify correlates associated with these behaviors. Correlates were organized as substance use behaviors, health outcomes (e.g., human immunodeficiency virus infection), or factors describing an individual's social, economic, policy, or physical environment, defined by means of Rhodes' risk environments framework. After screening of 1,164 abstracts, 57 studies were included. The prevalence of receiving assistance with injection initiation (help or guidance at the first injection) ranged 74% to 100% (n = 13 estimates). The prevalence of ever providing assistance with injection initiation varied widely (range, 13%-69%; n = 13 estimates). Injecting norms, sex/gender, and other correlates classified within Rhodes' social risk environment were commonly associated with providing and receiving assistance. Nearly all PWID receive guidance about injecting for the first time, whereas fewer PWID report providing assistance. Substantial clinical and statistical heterogeneity between studies precluded meta-analysis, and thus local-level estimates may be necessary to guide the implementation of future psychosocial and sociostructural interventions. Further, estimates of providing assistance may be downwardly biased because of social desirability factors.

The role of gender and power dynamics in injection initiation events within intimate partnerships in the US-Mexico border region

Women's initiation into injection drug use often establishes a pattern of risk following first injection. This study explored sources of gendered power dynamics in injection initiation experiences for people who inject drugs. A qualitative subsample from two prospective community-recruited cohorts of people who inject drugs in San Diego and Tijuana provided data on the contexts surrounding injection initiation processes. Intimate partnerships were identified in initiation; sub-themes were identified drawing on three concepts within the theory of gender and power. With reference to sexual division of labour, men were often responsible for access to resources in partnerships across both contexts, although there were limited accounts of women obtaining those resources. Extending the structure of power, women in San Diego reported that initiation events involving an intimate partner occurred from a position of vulnerability but expressed greater agency when providing initiation assistance. With regard to structure of cathexis, social norms proscribing injection initiation among women exist, particularly in Tijuana. Gendered power dynamics are a multifaceted component of injection initiation events, especially for women in intimate partnerships. These results stress the need for nuance in understanding the intersection of risk, gender and harm reduction within injection initiation events across socio-cultural contexts.

Injection drug network characteristics as a predictor of injection behaviour

Social network characteristics of people who inject drugs (PWID) have previously been flagged as potential risk factors for HCV transmission such as increased injection frequency. To understand the role of the injecting network on injection frequency, we investigated how changes in an injecting network over time can modulate injecting risk behaviour. PWID were sourced from the Networks 2 Study, a longitudinal cohort study of PWID recruited from illicit drug street markets across Melbourne, Australia. Network-related correlates of injection frequency and the change in frequency over time were analysed using adjusted Cox Proportional Hazards and Generalised Estimating Equations modelling. Two-hundred and eighteen PWID followed up for a mean (s.d.) of 2.8 (1.7) years were included in the analysis. A greater number of injecting partners, network closeness centrality and eigenvector centrality over time were associated with an increased rate of infection frequency. Every additional injection drug partner was associated with an increase in monthly injection frequency. Similarly, increased network connectivity and centrality over time was also associated with an increase in injection frequency. This study observed that baseline network measures of connectivity and centrality may be associated with changes in injection frequency and, by extension, may predict subsequent HCV transmission risk. Longitudinal changes in network position were observed to correlate with changes in injection frequency, with PWID who migrate from the densely-connected network centre out to the less-connected periphery were associated with a decreased rate of injection frequency.

Hepatitis C transmission in young people who inject drugs: Insights using a dynamic model informed by state public health surveillance

Increasing injection of heroin and prescription opioids have led to increases in the incidence of hepatitis C virus (HCV) infections in US young adults since the early 2000s. How best to interrupt transmission and decrease HCV prevalence in young people who inject drugs (PWID) is uncertain. We developed an age-stratified ordinary differential equation HCV transmission model of PWID aged 15-64, which we fit to Michigan HCV surveillance data among young PWID aged 15-29. We used Latin hypercube sampling to fit to data under 10,000 plausible model parameterizations. We used the best-fitting 10% of simulations to predict the potential impact of primary (reducing injection initiation), secondary (increasing cessation, reducing injection partners, or reducing injection drug use relapse), and tertiary (HCV treatment) interventions (over the period 2017-2030) on acute and chronic HCV cases by the year 2030. Treating 3 per 100 current and former PWID per year could reduce chronic HCV by 27.3% (range: 18.7-30.3%) and acute HCV by 23.6% (range: 6.7-29.5%) by 2030 among PWID aged 15-29 if 90% are cured (i.e. achieved sustained virologic response [SVR] to treatment). Reducing the number of syringe sharing partners per year by 10% was predicted to reduce chronic HCV by 15.7% (range: 9.4-23.8%) and acute cases by 21.4% (range: 14.2-32.3%) among PWID aged 15-29 by 2030. In simulations of combinations of interventions, reducing injection initiation, syringe sharing, and relapse rates each by 10% while increasing cessation rates by 10% predicted a 27.7% (range: 18.0-39.7%) reduction in chronic HCV and a 38.4% (range: 28.3-53.3%) reduction in acute HCV. Our results highlight the need for HCV treatment among both current and former PWID and the scale up of both primary and secondary interventions to concurrently reduce HCV prevalence and incidence in Michigan.

Gender differences in the provision of injection initiation assistance: a comparison of three North American settings

AIM

Individuals experience differential risks in their initiation into drug injecting based on their gender. Data suggest women are more likely to be injected after their initiator and to share injection equipment. Little is known, however, regarding how gender influences the risk that people who inject drugs (PWID) may assist others into injection initiation. We therefore sought to investigate the role of "initiator" gender in the provision of injection initiation assistance across multiple settings.

METHODS

We employed data from PReventing Injecting by Modifying Existing Responses (PRIMER), a multi-cohort study investigating factors influencing injection initiation assistance provision. Data were drawn from three cohort studies of PWID in San Diego, USA (STAHR II); Tijuana, Mexico (El Cuete IV); and Vancouver, Canada (VDUS). Site-specific logistic regression models were fit, with lifetime provision of injection initiation assistance as the outcome and gender as the independent variable.

RESULTS

Overall, 3.2% (24/746) of the women and 4.6% (63/1367) of the men reported providing injection initiation assistance. In Tijuana, men were more than twice as likely to have provided injection initiation assistance after controlling for potential confounders (adjusted odds ratio = 2.17, 95% confidence interval: 1.22-3.84). Gender was not significantly associated with providing injection initiation assistance in other sites.

CONCLUSION

We identified that being male in Tijuana, specifically, was associated with providing injection initiation assistance, which could inform targeted outreach aimed at reducing the influence of PWID populations on non-injectors in this site. This will likely require that existing interventions address gender- and site-specific factors for effectiveness.

Quantifying potentially infectious sharing patterns among people who inject drugs in Baltimore, USA

Mixing matrices quantify how people with similar or different characteristics make contact with each other, creating potential for disease transmission. Little empirical data on mixing patterns among persons who inject drugs (PWID) are available to inform models of blood-borne disease such as HIV and hepatitis C virus. Egocentric drug network data provided by PWID in Baltimore, Maryland between 2005 and 2007 were used to characterise drug equipment-sharing patterns according to age, race and gender. Black PWID and PWID who were single (i.e. no stable sexual partner) self-reported larger equipment-sharing networks than their white and non-single counterparts. We also found evidence of assortative mixing according to age, gender and race, though to a slightly lesser degree in the case of gender. Highly assortative mixing according to race and gender highlights the existence of demographically isolated clusters, for whom generalised treatment interventions may have limited benefits unless targeted directly. These findings provide novel insights into mixing patterns of PWID for which little empirical data are available. The age-specific assortativity we observed is also significant in light of its role as a key driver of transmission for other pathogens such as influenza and tuberculosis.

Association between injection in public places and HIV/HCV risk behavior among people who use drugs in Ukraine

BACKGROUND

In Eastern Europe and Central Asia new HIV infections occur at a high rate among people who inject drugs (PWID). Injection risk behavior may be associated with injecting in public places. However, there is a lack of studies exploring this association in Ukraine, which has an HIV prevalence 21-42% among PWID.

METHODS

Data came from a baseline survey of PWID recruited to participate in a behavioral HIV prevention intervention. The association between HIV/HCV injection risk behavior and place of injection (private vs. public) was assessed using multivariable Poisson regression with robust variance estimate.

RESULTS

Most of the sample was male (73%), > 30 years (56%), and reported opioids as their drug of choice (55%). One in six participants (15.8%, n = 57) reported using a syringe after somebody, and 70% (n = 253) reported injecting in public places within last 30-days. In the adjusted model, injection risk behavior was associated with injecting in public places (PrR: 4.24, 95% CI: 1.76-10.20), unstable housing situation (PrR: 2.46, 95% CI:1.26-4.83), higher than secondary education (PrR:1.82, 95%CI:1.04-3.16), injecting with a sex partner day (PrR:2.13, 95% CI:1.28-3.56), and injecting with a stranger (PrR: 1.47, 95% CI: 0.93-2.31).

CONCLUSIONS

Injecting in a public place is associated with increased prevalence of risky behavior. Therefore, understanding and addressing place-based context should be part of the national strategy to fight HIV and HCV in Ukraine. National programs would benefit from expanding models to include contextual and structural determinants of health.

Prevalence and correlates of HIV infection among men who inject drugs in a remote area of Vietnam

Background

Lack of information on the HIV epidemic among men who inject drugs (MWID) in northwestern Vietnam, a remote area, may hamper national efforts to control the disease. We examined HIV prevalence, needle–syringe sharing behaviors, and associated factors among MWID in three areas of northwestern Vietnam.

Methods

We used descriptive analysis to report the characteristics, frequency of risk behaviors, and of access to healthcare services among the MWID. Univariable logistic regression was used to assess the associations between the HIV infection, needle–syringe sharing behaviors, and their independent variables. We further explored these associations in multivariable analyses where we included independent variables based on a priori knowledge and their associations with the dependent variables determined in univariable analyses (p <  0.25).

Results

The HIV prevalence was 37.9, 16.9, and 18.5% for Tuan Giao, Bat Xat, and Lao Cai City, respectively, and 25.4% overall. MWID of Thai minority ethnicity were more likely to be HIV-positive (adjusted odds ratio (AOR) 3.55; 95% confidence interval (CI) 1.84–6.87). The rate of needle–syringe sharing in the previous 6 months was approximately 9% among the MWID in Tuan Giao and Lao Cai City, and 27.8% in Bat Xat. Two thirds of the participants never underwent HIV testing before this study. Ever having been tested for HIV before this study was not associated with any needle–syringe sharing behaviors. Among the HIV-positive MWID, those who received free clean needles and syringes were less likely to give used needles and syringes to peers (AOR 0.21; 95% CI 0.06–0.79). Going to a “hotspot” in the previous week was associated with increased odds of needle–syringe sharing in multiple subgroups.

Conclusion

Our findings on HIV prevalence and testing participation among a subset of MWID in the northwestern Vietnam were corroborated with trend analysis results from the most recent HIV/STI Integrated Biological and Behavioral Surveillance report (data last collected in 2013.) We provided important insights into these MWID’s risky injection behaviors. We suggest heightened emphasis on HIV testing and needle and syringe provision for this population. Also, policymakers and program implementers should target hotspots as a main venue to tackle HIV epidemics.

The experience of initiating injection drug use and its social context: a qualitative systematic review and thematic synthesis

BACKGROUND AND AIM

Understanding the experience of initiating injection drug use and its social contexts is crucial to inform efforts to prevent transitions into this mode of drug consumption and support harm reduction. We reviewed and synthesized existing qualitative scientific literature systematically to identify the socio-structural contexts for, and experiences of, the initiation of injection drug use.

METHODS

We searched six databases (Medline, Embase, PsychINFO, CINAHL, IBSS and SSCI) systematically, along with a manual search, including key journals and subject experts. Peer-reviewed studies were included if they qualitatively explored experiences of or socio-structural contexts for injection drug use initiation. A thematic synthesis approach was used to identify descriptive and analytical themes throughout studies.

RESULTS

From 1731 initial results, 41 studies reporting data from 1996 participants were included. We developed eight descriptive themes and two analytical (higher-order) themes. The first analytical theme focused on injecting initiation resulting from a social process enabled and constrained by socio-structural factors: social networks and individual interactions, socialization into drug-using identities and choices enabled and constrained by social context all combine to produce processes of injection initiation. The second analytical theme addressed pathways that explore varying meanings attached to injection initiation and how they link to social context: seeking pleasure, responses to increasing tolerance to drugs, securing belonging and identity and coping with pain and trauma.

CONCLUSIONS

Qualitative research shows that injection drug use initiation has varying and distinct meanings for individuals involved and is a dynamic process shaped by social and structural factors. Interventions should therefore respond to the socio-structural influences on injecting drug use initiation by seeking to modify the contexts for initiation, rather than solely prioritizing the reduction of individual harms through behavior change.

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.

Identifying and characterizing hepatitis C virus hotspots in Massachusetts: a spatial epidemiological approach

Background

Hepatitis C virus (HCV) infections have increased during the past decade but little is known about geographic clustering patterns.

Methods

We used a unique analytical approach, combining geographic information systems (GIS), spatial epidemiology, and statistical modeling to identify and characterize HCV hotspots, statistically significant clusters of census tracts with elevated HCV counts and rates. We compiled sociodemographic and HCV surveillance data (n = 99,780 cases) for Massachusetts census tracts (n = 1464) from 2002 to 2013. We used a five-step spatial epidemiological approach, calculating incremental spatial autocorrelations and Getis-Ord Gi* statistics to identify clusters. We conducted logistic regression analyses to determine factors associated with the HCV hotspots.

Results

We identified nine HCV clusters, with the largest in Boston, New Bedford/Fall River, Worcester, and Springfield (p < 0.05). In multivariable analyses, we found that HCV hotspots were independently and positively associated with the percent of the population that was Hispanic (adjusted odds ratio [AOR]: 1.07; 95% confidence interval [CI]: 1.04, 1.09) and the percent of households receiving food stamps (AOR: 1.83; 95% CI: 1.22, 2.74). HCV hotspots were independently and negatively associated with the percent of the population that were high school graduates or higher (AOR: 0.91; 95% CI: 0.89, 0.93) and the percent of the population in the “other” race/ethnicity category (AOR: 0.88; 95% CI: 0.85, 0.91).

Conclusion

We identified locations where HCV clusters were a concern, and where enhanced HCV prevention, treatment, and care can help combat the HCV epidemic in Massachusetts. GIS, spatial epidemiological and statistical analyses provided a rigorous approach to identify hotspot clusters of disease, which can inform public health policy and intervention targeting. Further studies that incorporate spatiotemporal cluster analyses, Bayesian spatial and geostatistical models, spatially weighted regression analyses, and assessment of associations between HCV clustering and the built environment are needed to expand upon our combined spatial epidemiological and statistical methods.

Transmission of hepatitis C virus infection among younger and older people who inject drugs in Vancouver, Canada

BACKGROUND & AIMS

Understanding HCV transmission among people who inject drugs (PWID) is important for designing prevention strategies. This study investigated whether HCV infection among younger injectors occurs from few or many transmission events from older injectors to younger injectors among PWID in Vancouver, Canada.

METHODS

HCV antibody positive participants at enrolment or follow-up (1996-2012) were tested for HCV RNA and sequenced (Core-E2). Time-stamped phylogenetic trees were inferred using Bayesian Evolutionary Analysis Sampling Trees (BEAST). Association of age with phylogeny was tested using statistics implemented in the software Bayesian Tip Significance (BaTS) testing. Factors associated with clustering (maximum cluster age: five years) were identified using logistic regression.

RESULTS

Among 699 participants with HCV subtype 1a, 1b, 2b and 3a infection (26% female, 24% HIV+): 21% were younger (<27years), and 10% had recent HCV seroconversion. When inferred cluster age was limited to <5years, 15% (n=108) were in clusters/pairs. Although a moderate degree of segregation was observed between younger and older participants, there was also transmission between age groups. Younger age (<27 vs. >40, AOR: 3.14; 95% CI: 1.54, 6.39), HIV (AOR: 1.97; 95% CI: 1.22, 3.18) and subtype 3a (AOR: 2.12; 95% CI: 1.33, 3.38) were independently associated with clustering.

CONCLUSIONS

In this population of PWID from Vancouver, HCV among young injectors was seeded from many transmission events between HCV-infected older and younger injectors. Phylogenetic clustering was associated with younger age and HIV. These data suggest that HCV transmission among PWID is complex, with transmission occurring between and among older and younger PWID.

Burden of blood transmitted infections in substance users admitted for inpatient treatment in Singapore and the associated factors

INTRODUCTION

There is paucity of local data on the prevalence of blood transmitted infections (BTIs), such as hepatitis B, hepatitis C and human immunodeficiency virus (HIV) infections, among illicit drug users. This study aimed to examine the prevalence of BTIs among substance dependent inpatients and identify the factors associated with BTIs.

METHODS

We conducted a retrospective analysis of clinical notes of 170 inpatients with a diagnosis of substance dependence who were admitted at the National Addictions Management Service, Singapore, between 1 June 2009 and 31 May 2010.

RESULTS

Majority of the 170 inpatients were male (88.2%) and Chinese (58.2%). The mean age of the patients was 43.1 years, and the main drug of abuse was opioids (86.5%). BTIs were found in 70 (41.2%) inpatients; the prevalence of hepatitis B, hepatitis C and HIV infections was 3.7%, 39.6% and 0%, respectively. Lifetime intravenous drug use, but not needle-sharing, was more common among inpatients who were positive for BTIs (p < 0.01). Logistic regression analysis showed that lifetime intravenous drug use (OR 4.3, 95% CI 1.7- 10.8, p < 0.01) was the only significant predictor of BTIs.

CONCLUSION

A large proportion (41.2%) of the substance users seeking help was positive for at least one BTI. Lifetime intravenous drug users were found to be more than four times more likely to have a BTI. Early detection and prevention is essential to improve prognosis.

Impact of hepatitis C status on 20-year mortality of patients with substance use disorders

Background

The magnitude of the effect of hepatitis C viral infection on survival is still not fully understood. The objective of this study was to determine whether the presence of hepatitis C viral antibodies in 1991 was associated with increased mortality 20 years later within a cohort of patients with substance use disorders. Secondary objectives were to determine other factors that were associated with increased mortality in the cohort.

Methods

A subset of a 1991 study cohort of patients who had presented for detoxification was reexamined 20 years later. The Social Security Death Index was queried to identify which of the original patients had died. Attributes of survivors and non-survivors were compared, with special attention to their hepatitis C status in 1991. The original study and this analysis were conducted in the chemical detoxification unit at Johns Hopkins Bayview (previously Francis Scott Key Hospital), an academic urban hospital. All participants met the criteria for alcohol or opioid dependence at the time of admission in 1991. The primary study outcome was 20-year mortality after initial admission in 1991, with a planned analysis of hepatitis C status.

Results

Twenty years after admission, 362 patients survived and 82 had died. Of the 284 patients who were hepatitis C positive, 228 survived (80 %). Of the 160 patients who were hepatitis C negative, 134 survived (84 %). This absolute risk increase of 4 % was not statistically significant (p = 0.37). Factors associated with increased mortality included male sex, white race, older age, and reported use of alcohol, cocaine, and illicit methadone. Binary logistic regression including hepatitis C status and these other variables yielded an adjusted odds ratio of 0.87 (95 % CI 0.49–1.55); (p = 0.64) for hepatitis C positive 20-year survival.

Conclusions

Hepatitis C positivity was not associated with a statistically significant difference in 20-year survival. The effect of the virus on mortality, if present, is small, relative to the effect of substance use disorders alone.

The role of social networks and geography on risky injection behaviors of young persons who inject drugs

BACKGROUND

Little is known about young persons who inject drugs (PWID), who are increasingly from suburban communities and predominantly non-Hispanic white.

METHODS

We conducted a cross-sectional personal network (egocentric) and geographic study of young PWID and their drug-using, sexual, and support network members in 2012-13 in metropolitan Chicago, Illinois, U.S.

RESULTS

We enrolled 164 young (median age=26), mostly male (65%), non-Hispanic white PWID (71%), with a self-reported HCV prevalence of 13%. Many (59%) reported multiple residences (i.e., were transient) in the past year, 45% of whom reported living in both urban and suburban places (i.e., were cross-over transients). In multivariable analyses that adjusted for participant and network member characteristics, (1) large injection networks were more common among homeless participants; and (2) syringe sharing was (a) highest among cross-over transients compared to suburban (OR=4.19 95% CI 1.69-10.35) and urban only residents (OR=2.91 95% CI 1.06-8.03), (b) higher among HCV-unknown compared HCV-negative participants (OR=4.62 95% CI 1.69-10.35), (c) more likely with network members who were cross-over transients compared to urban (OR=4.94, 95% CI 2.17-11.23) and (d) less likely with network members with HCV-unknown compared to HCV-negative status (OR=0.4 95% CI 0.19-0.84).

CONCLUSIONS

We identified homelessness as a significant risk factor for large networks and cross-over transience as a significant risk factor for syringe sharing. Further research is needed to understand the role of geographic factors promoting higher risk among these crossover transient PWID.

Demographic characteristics and intravenous drug use among hepatitis C patients in the Kota Setar district, Kedah, Malaysia

OBJECTIVES:

This study explored the demographic characteristics of hepatitis C patients in the Kota Setar (KS) district, Kedah, Malaysia, the prevalence of intravenous drug use (IVDU) as a risk factor among these patients, and the associations between IVDU and demographic characteristics.

METHODS:

Retrospective data pertaining to 713 patients from January 2009 to December 2013 were retrieved from hospital and disease notification records for analysis. The risk factors for hepatitis C virus (HCV) infection were grouped into IVDU and non-IVDU risk factors for analysis using multiple logistic regression.

RESULTS:

Of the hepatitis C patients included in this study, the most common age group was 31 to 40 years (30.2%), and male patients (91.2%) made up the overwhelming majority. Ethnic Malays constituted approximately 80.4% of the patients, and IVDU was the main risk factor (77.8%) for HCV infection. Multiple logistic regression showed that male patients were 59 times more likely to have IVDU as a risk factor for HCV infection. Single patients were 2.5 times more likely to have IVDU as a risk factor. Patients aged ≥71 years were much less likely than patients aged ≤30 years to have IVDU as a risk factor for HCV infection.

CONCLUSIONS:

IVDU was found to be an important risk factor for HCV infection among patients in the KS district. The factors associated with IVDU included age, sex, and marital status. Appropriate preventive measures should be developed to target the groups in which IVDU is most likely to be a risk factor for HCV infection.

HIV and STI prevalence and injection behaviors among people who inject drugs in Nairobi: results from a 2011 bio-behavioral study using respondent-driven sampling

There is a dearth of evidence on injection drug use and associated HIV infections in Kenya. To generate population-based estimates of characteristics and HIV/STI prevalence among people who inject drugs (PWID) in Nairobi, a cross-sectional study was conducted with 269 PWID using respondent-driven sampling. PWID were predominantly male (92.5 %). An estimated 67.3 % engaged in at least one risky injection practice in a typical month. HIV prevalence was 18.7 % (95 % CI 12.3–26.7), while STI prevalence was lower [syphilis: 1.7 % (95 % CI 0.2–6.0); gonorrhea: 1.5 % (95 % CI 0.1–4.9); and Chlamydia: 4.2 % (95 % CI 1.2–7.8)]. HIV infection was associated with being female (aOR, 3.5; p = 0.048), having first injected drugs 5 or more years ago (aOR, 4.3; p = 0.002), and ever having practiced receptive syringe sharing (aOR, 6.2; p = 0.001). Comprehensive harm reduction programs tailored toward PWID and their sex partners must be fully implemented as part of Kenya’s national HIV prevention strategy.

The impact of injecting networks on hepatitis C transmission and treatment in people who inject drugs

With the development of new highly efficacious direct-acting antiviral (DAA) treatments for hepatitis C virus (HCV), the concept of treatment as prevention is gaining credence. To date, the majority of mathematical models assume perfect mixing, with injectors having equal contact with all other injectors. This article explores how using a networks-based approach to treat people who inject drugs (PWID) with DAAs affects HCV prevalence. Using observational data, we parameterized an exponential random graph model containing 524 nodes. We simulated transmission of HCV through this network using a discrete time, stochastic transmission model. The effect of five treatment strategies on the prevalence of HCV was investigated; two of these strategies were (1) treat randomly selected nodes and (2) "treat your friends," where an individual is chosen at random for treatment and all their infected neighbors are treated. As treatment coverage increases, HCV prevalence at 10 years reduces for both the high- and low-efficacy treatment. Within each set of parameters, the treat your friends strategy performed better than the random strategy being most marked for higher-efficacy treatment. For example, over 10 years of treating 25 per 1,000 PWID, the prevalence drops from 50% to 40% for the random strategy and to 33% for the treat your friends strategy (6.5% difference; 95% confidence interval: 5.1-8.1).

CONCLUSION

Treat your friends is a feasible means of utilizing network strategies to improve treatment efficiency. In an era of highly efficacious and highly tolerable treatment, such an approach will benefit not just the individual, but also the community more broadly by reducing the prevalence of HCV among PWID.

Associations between prescription opioid injection and Hepatitis C virus among young injection drug users

OBJECTIVE

Hepatitis C virus (HCV) incidence has been increasing among young injection drug users (IDUs). This analysis examined whether the emerging practice of prescription opioid (PO) injection is associated with self-reported HCV among young IDUs.

METHODS

Young IDUs (n = 162) aged 18-25-years-old who indicated recent misuse of prescription drugs were sampled in New York and Los Angeles during 2009-2011. Participants reported lifetime PO injection history and results from their most recent HCV test as well as demographic characteristics and lifetime drug use. Bivariate analyses examined relationships between covariates and both lifetime PO injection and HCV positivity. Poisson regression examined the associations between lifetime PO injection, HCV positivity, and significant covariates.

RESULTS

A majority reported lifetime PO injection (72.2%) and 30.9% self-reported being HCV positive. Lifetime PO injectors were nearly three times more likely to report being HCV positive than non-PO injectors (adjusted incidence rate ratio (AIRR): 2.69, p<0.05) after controlling for socio-demographic and other drug use variable. Additionally, substituting POs for heroin (AIRR: 2.27, p<0.05), growing up in a lower social class (AIRR: 1.67, p<0.05), age (AIRR: 1.12, p<0.05), age of injection initiation (AIRR: 0.87, p<0.001), and history of being prescribed stimulants (AIRR: 0.64, p<0.05) were independently associated with HCV positivity.

CONCLUSIONS

Findings suggest that PO injection should be given further consideration as a contributing factor to rising HCV infection among young adults in the US.

Can hepatitis C be eradicated in the United States?

The advent of highly effective antiviral regimens will make the eradication of hepatitis C in high-income countries such as the United States technically feasible. But eradicating hepatitis C will require escalating our response to the epidemic in key domains, including surveillance and epidemiology, prevention, screening, care and treatment, policy, research, and advocacy. Surveillance must be nimble enough to quickly assess the magnitude of new transmission patterns as they emerge. Basic prevention strategies - community-based outreach and education, testing and counseling, and access to sterile injection equipment and opioid substitution therapies - must be scaled up and adapted to target groups in which new epidemics are emerging. All adults should be screened for hepatitis C, but special efforts must focus on groups with increased prevalence through community outreach and rapid testing. Government, industry, and payers must work together to assure full access to health services and antiviral drugs for everyone who is infected. Access to the new regimens must not be compromised by excessively high prices or arbitrary payer restrictions. Partnerships must be forged between hepatitis providers and programs that serve people who inject illicit drugs. Healthcare providers and systems, especially primary care practitioners, need education and training in treating hepatitis C and caring for substance-using populations. Services must be provided to the disadvantaged and stigmatized members of society who bear a disproportionate burden of the epidemic. Environments must be created where people who use drugs can receive prevention and treatment services without shame or stigma. Action is needed to end the policy of mass incarceration of people who use drugs, reduce the stigma associated with substance use, support the human rights of people who use drugs, expand social safety net services for the poor and the homeless, remove the legal barriers to hepatitis C prevention, and build public health infrastructure to reach, engage, and serve marginalized populations. Governments must take action to bring about these changes. Public health agencies must work with penal institutions to provide prevention and treatment services, including antiviral therapy, to those in need in jails and prisons or on probation or parole. Research is needed to guide efforts in each of these domains. Strong and sustained political advocacy will be needed to build and sustain support for these measures. Leadership must be provided by physicians, scientists, and the public health community in partnership with community advocates and people living with or at risk for hepatitis C. Eliminating hepatitis C from the United States is possible, but will require a sustained national commitment to reach, test, treat, cure, and prevent every case. With strong political leadership, societal commitment, and community support, hepatitis C can be eradicated in the United States. If this is to happen in our lifetimes, the time for action is now. This article forms part of a symposium in Antiviral Research on "Hepatitis C: next steps toward global eradication."

Prescription opioid injection and risk of hepatitis C in relation to traditional drugs of misuse in a prospective cohort of street youth

OBJECTIVE

Despite dramatic increases in the misuse of prescription opioids, the extent to which their intravenous injection places drug users at risk of acquiring hepatitis C virus (HCV) remains unclear. We sought to compare risk of HCV acquisition from injection of prescription opioids to that from other street drugs among high-risk street youth.

DESIGN

Prospective cohort study.

SETTING

Vancouver, British Columbia, Canada from September 2005 to November 2011.

PARTICIPANTS

The At-Risk Youth Study (ARYS) is a prospective cohort of drug-using adolescents and young adults aged 14-26 years. Participants were recruited through street-based outreach and snowball sampling.

PRIMARY OUTCOME MEASURE

HCV antibody seroconversion, measured every 6 months during follow-up. Risk for seroconversion from injection of prescription opioids was compared with injection of other street drugs of misuse, including heroin, cocaine or crystal methamphetamine, using Cox proportional hazards regression controlling for age, gender and syringe sharing.

RESULTS

Baseline HCV seropositivity was 10.6%. Among 512 HCV-seronegative youth contributing 860.2 person-years of follow-up, 56 (10.9%) seroconverted, resulting in an incidence density of 6.5/100 person-years. In bivariate analyses, prescription opioid injection (HR=3.48; 95% CI 1.57 to 7.70) predicted HCV seroconversion. However, in multivariate modelling, only injection of heroin (adjusted HR=4.56; 95% CI 2.39 to 8.70), cocaine (adjusted HR=1.88; 95% CI 1.00 to 3.54) and crystal methamphetamine (adjusted HR=2.91; 95% CI 1.57 to 5.38) remained independently associated with HCV seroconversion, whereas injection of prescription opioids did not (adjusted HR=0.94; 95% CI 0.40 to 2.21).

CONCLUSIONS

Although misuse of prescription opioids is on the rise, traditional street drugs still posed the greatest threat of HCV transmission in this setting. Nonetheless, the high prevalence and incidence of HCV among Canadian street youth underscore the need for evidence-based drug prevention, treatment and harm reduction interventions targeting this vulnerable population.

Prevalence of HIV infection and risk behaviors among younger and older injecting drug users in the United States, 2009

This study compared HIV sero-prevalence and risk behaviors between younger and older injecting drug users (IDUs). IDUs aged ≥18 years were interviewed for the 2009 National HIV Behavioral Surveillance System. Using GEE regression, we assessed characteristics of younger (18-29 years) and older (≥30 years) IDUs, and factors associated with past 12-month receptive syringe sharing and unprotected sex (vaginal/anal). Of 10,090 participants, 10 % were younger. HIV sero-prevalence was lower among younger than older IDUs (4 vs. 10 %, p = 0.001). Younger IDUs were more likely (p ≤ 0.002) to be non-black race/ethnicity, report higher household income, homelessness, being arrested and to engage in receptive syringe sharing and unprotected sex. In multivariable models, age remained associated (p < 0.001) with receptive syringe sharing (aPR = 1.14, 95 % CI1.07-1.22) and unprotected sex (aPR = 1.10, 95 % CI1.06-1.14). Although younger IDUs had lower HIV prevalence, their behaviors place them at increased risk of HIV infection and could lead to a rapid spread in this susceptible population.

Increasing hepatitis C prevalence and associated risk behaviors among incarcerated young adults

This study sought to assess the rate of hepatitis C virus (HCV) infection and associated risk factors in young adults 18-28 years of age who were incarcerated in the Rhode Island Department of Corrections. The majority of participants reported injection drug use and engaged in high-risk behaviors such as needle sharing. Despite having these risk factors and believing themselves to be at risk, the majority of youths reported no prior HCV testing. Correctional facilities present a unique opportunity to detect HCV infection and provide risk reduction education to young adults, the population with the highest rates of new infections in the US. Seventy-two incarcerated individuals with a history of drug use were approached to participate in the study; 68 completed the screening and interview. The rate of HCV infection among adults <30 years of age and incarcerated at the Rhode Island Department of Corrections in 2011 was high (24%). In 1998, the rate of HCV among inmates <30 years of age at the same facility was only 11.4%. These data follow the same increase in HCV infection rates among young adults observed in non-incarcerated young adults across the nation. HCV is the leading cause of liver failure and hepatocellular carcinoma in the US. Despite a decline and leveling in HCV incidence nationwide, alarming increases in HCV rates among adolescents and young adults have been reported during the period between the years 1992 and 2005. This disquieting epidemic is attributable to injection drug use amongst young adults.

Hepatitis C virus vaccines among people who inject drugs

Most people who inject drugs (PWID) are infected with hepatitis C virus (HCV), and PWID have the highest risk of HCV infection of any risk group. The incidence of HCV infection is 5%-25% per year, demonstrating continued need for HCV infection prevention in PWID. Existing data in chimpanzees and PWID suggest that protective immunity against persistent HCV infection is achievable. Due to the high incidence of infection, PWID are both the most likely to benefit from a vaccine and a population in which vaccine efficacy could be tested. Challenges to testing a vaccine in PWID are significant. However, the first HCV vaccine trial in at-risk HCV-uninfected PWID was initiated in 2012. The results will likely guide future vaccine development and strategies for vaccination of this and other high-risk populations.

Age and sharing of needle injection equipment in a cohort of Massachusetts injection drug users: an observational study

BACKGROUND

Hepatitis C infection (HCV) among individuals aged 15-24 years has increased in Massachusetts, likely due to injection drug use. The prevalence of injection equipment sharing (sharing) and its association with age was examined in a cohort of out-of-treatment Massachusetts substance users.

METHODS

This analysis included baseline data from a behavioral intervention with substance users. Younger and older (<25 versus ≥ 25 years) injection drug users were compared on demographic characteristics, substance use practices, including factors present during the most recent sharing event ("event-level factors"), and HCV testing history.

RESULTS

Sharing was reported by 41% of the 484 individuals who reported injection drug use in the past 30 days. Prevalence of sharing varied by age (50% <25 years old versus 38% ≥ 25 years, p=0.02). In a multivariable logistic regression model younger versus older individuals had twice the odds of sharing (95% CI=1.26, 3.19). During their most recent sharing event, fewer younger individuals than older had their own drugs available (50% versus 75%, p<0.001); other injection event-level factors did not vary by age. In the presence of PTSD, history of exchanging sex for money, or not being US born, prevalence of sharing by older users was higher and was similar to that of younger users, such that there was no association between age and sharing.

CONCLUSIONS

In this cohort of injection drug users, younger age was associated with higher prevalence of sharing, but only in the absence of certain stressors. Harm reduction efforts might benefit from intervening on mental health and other stressors in addition to substance use. Study findings suggest a particular need to address the dangers of sharing with young individuals initiating injection drug use.

Missed opportunities for hepatitis C testing in opioid treatment programs

HCV has surpassed HIV as a cause of death in the United States and is particularly prevalent among injection drug users. I examined the availability of on-site HCV testing in a nationally representative sample of opioid treatment programs. Nearly 68% of these programs had the staff required for HCV testing, but only 34% offered on-site testing. Availability of on-site testing increased only slightly with the proportion of injection drug users among clients. The limited HCV testing services in opioid treatment programs is a key challenge to reducing HCV in the US population.

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.

A profile on HIV prevalence and risk behaviors among injecting drug users in Nigeria: should we be alarmed?

OBJECTIVE

Injecting drug use is now recognized as a significant risk factor for HIV in sub-Saharan Africa. We evaluated prevalence and correlates of HIV among injecting drug users (IDUs) in Nigeria.

METHODS

A cross sectional design using respondent driven sampling was conducted in six states in 2010. Weighted HIV prevalence and injecting risk behaviors calculated using RDS analytic tool. Logistic regression was used to determine correlates of HIV infection, stratified by state.

RESULTS

Total numbers of IDUs ranged from 197 in Lagos to 273 in Cross River and Oyo states. HIV prevalence was highest in Federal Capital Territory (FCT) at 9.3%, Kaduna 5.8%, Oyo 5.1%, Kano 4.9%, CR 3.3% and Lagos 3.0%. Although >90% of participants were male, females had higher HIV prevalence in all states surveyed except FCT (range: 7.4% in CR to 37.7% in Kano). Logistic regression showed that females were significantly more likely to be HIV positive in Kano [OR=33.2, 95% CI: 6.8-160.4], Oyo [AOR=15.9, 95% CI: 3.69-68.51], Lagos [OR=15.5, 95% CI: 2.41-99.5] and Kaduna states [AOR=19.6, 95% CI: 4.4-87.6]. For injecting risk behavior, only receptive sharing was associated with HIV [AOR=7.6, 95% CI: 1.2-48.7] and [AOR=0.2, 95% CI: 0.04-0.92] in Oyo and Kaduna states respectively.

CONCLUSIONS

Considerable heterogeneity in the prevalence of HIV and associated risk behaviors exist among IDUs across Nigeria. Females had higher HIV prevalence among IDUs in five of six states, suggesting a need for targeted interventions for this hidden subgroup. Further research is needed to understand HIV transmission dynamics of IDUs in Nigeria. Community-based opioid substitution therapy and needle exchange programs should be implemented without delay.

Hazardous alcohol consumption among young adult IDU and its association with high risk behaviors

BACKGROUND

Heavy alcohol consumption has been associated with risk-taking behaviors in intravenous drug users (IDU). However, limited information exists on the relationship between alcohol use and injecting and sexual risk in young adult IDU (<30 years) who are at risk for hepatitis C virus (HCV) and HIV infection.

METHODS

We conducted a cross-sectional study of young adult IDU in San Francisco (2006-2012) who had not previously tested positive for HCV. Participants completed a structured interview and HCV testing. We examined whether hazardous drinking (Alcohol Use Disorders Test-Consumption [AUDIT-C] 3-9 for women and 4-9 for men) and probable dependent drinking (AUDIT-C 10-12) levels were associated with injecting and sexual risk behaviors and HCV status, indicated by adjusted odds ratios (AOR) in separate models controlling for potential confounders.

RESULTS

Of the 326 participants, 139 (42.6%) were hazardous drinkers and 82 (25.2%) were probable dependent drinkers; thus over two-thirds evidenced problem drinking. Being a hazardous drinker was significantly associated with injecting drug residue from another's drug preparation equipment (AOR 1.93). Probable dependent drinking was significantly associated with sharing non-sterile drug preparation equipment (AOR 2.59), and inversely, with daily/near daily injecting (AOR 0.42). Both heavy drinking levels were associated with having ≥2 sexual partners (AOR 2.43 and 2.14). Drinking category was not associated with HCV test results.

CONCLUSION

The young adult IDU reported consuming alcohol at very high levels, which was associated with some unsafe sexual and injecting behaviors. Our study demonstrates the urgent need to intervene to reduce alcohol consumption in this population.

Rapid diagnostic HCV antibody assays

Approximately 4.1 million Americans have been infected with HCV and 45-85% of chronically infected persons are unaware of their status. Rapid anti-HCV assays can assist and expedite the identification of those unaware of their infection. Performance characteristics of pre-market rapid anti-HCV assays (Chembio, MedMira and OraSure) have been evaluated. Their sensitivity (78.9-99.3%) and specificity (80-100%) varied. Future investigations could include evaluation of rapid anti-HCV tests in persons who are coinfected with HCV and HIV, and development of rapid HCV-antigen tests and nucleic acid tests.

Individual and network factors associated with prevalent hepatitis C infection among rural Appalachian injection drug users

OBJECTIVES

We determined the factors associated with hepatitis C (HCV) infection among rural Appalachian drug users.

METHODS

This study included 394 injection drug users (IDUs) participating in a study of social networks and infectious disease risk in Appalachian Kentucky. Trained staff conducted HCV, HIV, and herpes simplex-2 virus (HSV-2) testing, and an interviewer-administered questionnaire measured self-reported risk behaviors and sociometric network characteristics.

RESULTS

The prevalence of HCV infection was 54.6% among rural IDUs. Lifetime factors independently associated with HCV infection included HSV-2, injecting for 5 or more years, posttraumatic stress disorder, injection of cocaine, and injection of prescription opioids. Recent (past-6-month) correlates of HCV infection included sharing of syringes (adjusted odds ratio = 2.24; 95% confidence interval = 1.32, 3.82) and greater levels of eigenvector centrality in the drug network.

CONCLUSIONS

One factor emerged that was potentially unique to rural IDUs: the association between injection of prescription opioids and HCV infection. Therefore, preventing transition to injection, especially among prescription opioid users, may curb transmission, as will increased access to opioid maintenance treatment, novel treatments for cocaine dependence, and syringe exchange.

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.

Correlates and contexts of US injection drug initiation among undocumented Mexican migrant men who were deported from the United States

Preventing the onset of injection drug use is important in controlling the spread of HIV and other blood borne infections. Undocumented migrants in the United States face social, economic, and legal stressors that may contribute to substance abuse. Little is known about undocumented migrants' drug abuse trajectories including injection initiation. To examine the correlates and contexts of US injection initiation among undocumented migrants, we administered quantitative surveys (N = 309) and qualitative interviews (N = 23) on migration and drug abuse experiences to deported male injection drug users in Tijuana, Mexico. US injection initiation was independently associated with ever using drugs in Mexico pre-migration, younger age at first US migration, and US incarceration. Participants' qualitative interviews contextualized quantitative findings and demonstrated the significance of social contexts surrounding US injection initiation experiences. HIV prevention programs may prevent/delay US injection initiation by addressing socio-economic and migration-related stressors experienced by undocumented migrants.

Evolving epidemiology of hepatitis C virus in the United States

The impact of hepatitis C virus (HCV) infection on health and medical care in the United States is a major problem for infectious disease physicians. Although the incidence of HCV infection has declined markedly in the past 2 decades, chronic infection in 3 million or more residents now accounts for more disease and death in the United States than does human immunodeficiency virus (HIV)/AIDS. Current trends in the epidemiology of HCV infection include an apparent increase in young, often suburban heroin injection drug users who initiate use with oral prescription opioid drugs; infections in nonhospital healthcare (clinic) settings; and sexual transmission among HIV-infected persons. Infectious disease physicians will increasingly have the responsibility of diagnosing and treating HCV patients. An understanding of how these patients were infected is important for determining whom to screen and treat.

Demographic, risk, and spatial factors associated with over-the-counter syringe purchase among injection drug users

Since 2005, California law allowed over-the-counter (OTC) syringe sales pending local authorization. Although pharmacy sales of OTC syringes are associated with reduced injection-mediated risks and decreases in human immunodeficiency virus infection rates, little is known about the factors associated with syringe purchase among injection drug users (IDUs). Using a cross-sectional design, the authors applied targeted sampling to collect quantitative survey data from IDUs (n = 563) recruited in San Francisco, California, during 2008. They also compiled a comprehensive list of retail pharmacies, their location, and whether they sell OTC syringes. They used a novel combination of geographic information system and statistical analyses to determine the demographic, behavioral, and spatial factors associated with OTC syringe purchase by IDUs. In multivariate analyses, age, race, injection frequency, the type of drug injected, and the source of syringe supply were independently associated with OTC syringe purchases. Notably, the prevalence of OTC syringe purchase was 53% lower among African-American IDUs (adjusted prevalence ratio = 0.47, 95% confidence interval: 0.33, 0.67) and higher among injectors of methamphetamine (adjusted prevalence ratio = 1.35, 95% confidence interval: 1.07, 1.70). Two neighborhoods with high densities of IDUs had limited access to OTC syringes. Increased access to OTC syringes would potentially prevent blood-borne infectious diseases among IDUs.

Meta-analysis of hepatitis C seroconversion in relation to shared syringes and drug preparation equipment

AIMS

We conducted a systematic review of studies reporting seroincidence of hepatitis C infection (HCV) in relation to shared syringes and drug preparation equipment among injection drug users (IDUs). We identified published and unpublished studies that met inclusion criteria.

DESIGN

We estimated the relative contributions of shared syringes and drug preparation equipment to HCV transmission using random-effects meta-analysis, and analyzed potential sources of heterogeneity of effects among studies.

FINDINGS

Syringe sharing was associated with HCV seroconversion [pooled risk ratio (PRR) = 1.94, 95% confidence interval (CI) 1.53, 2.46], as was sharing drug preparation containers (PRR = 2.42, 95% CI 1.89, 3.10), filters (PRR = 2.61, 95% CI 1.91, 3.56), rinse water (PRR = 1.98, 95% CI 1.54, 2.56), combinations of this equipment (PRR = 2.24, 95% CI 1.28, 3.93) and 'backloading', a syringe-mediated form of sharing prepared drugs (PRR = 1.86, 95% CI 1.41, 2.44). Meta-regression results showed that the association between syringe sharing and seroconversion was modified by HCV seroprevalence in the IDU populations.

CONCLUSIONS

The risk of hepatitis C infection through shared syringes is dependent upon hepatitis C infection seroprevalence in the population. The risk of hepatitis C infection through shared drug preparation equipment is similar to that of shared syringes. Because the infection status of sharing partners is often unknown, it is important for injection drug users to consistently avoid sharing unsterile equipment used to prepare, divide or inject drugs and avoid backloading with an unsterile syringe.

Motivators and barriers influencing willingness to participate in candidate HCV vaccine trials: perspectives of people who inject drugs

BACKGROUND

A safe and efficacious vaccine may be the most efficient and cost-effective strategy for controlling the hepatitis C virus (HCV) epidemic among people who inject drugs (PWID) and several candidates are in development. However, little is known about the factors that influence willingness to participate (WTP) in candidate HCV vaccine trials among this group.

METHODS

HCV seronegative PWID recruited between 2008 and 2010 as part of a prospective observational cohort study in Sydney, Australia were asked whether they would be willing to participate in a future candidate hepatitis C vaccine trial and to provide reasons to explain their decision.

RESULTS

Of 113 participants, 74% indicated WTP, 15% were unwilling to participate and 11% reported WTP that was contingent on vaccine characteristics and trial design issues. The most commonly reported motivator for hypothetical trial participation was altruism, followed by potential health benefits, financial remuneration, and knowledge gain. Barriers to hypothetical participation included fears about possible harms to health, such as concerns about vaccine safety, side effects, and acquiring HCV from the vaccine; other barriers included mistrust of biomedical research and time constraints.

CONCLUSIONS

These results may be useful in designing strategies to enhance HCV vaccine trial recruitment and retention and have ethical implications for developing informed consent processes and standards of care.