HCV Synthesis Project: Preliminary analyses of HCV prevalence in relation to age and duration of injection

Incidence of HIV and hepatitis C virus among people who inject drugs, and associations with age and sex or gender: a global systematic review and meta-analysis

BACKGROUND

Measuring the incidence of HIV and hepatitis C virus (HCV) infection among people who inject drugs (PWID) is key to track progress towards elimination. We aimed to summarise global data on HIV and primary HCV incidence among PWID and associations with age and sex or gender.

METHODS

In this systematic review and meta-analysis, we updated an existing database of HIV and HCV incidence studies among PWID by searching MEDLINE, Embase, and PsycINFO, capturing studies published between Jan 1, 2000, and Dec 12, 2022, with no language or study design restrictions. We contacted authors of identified studies for unpublished or updated data. We included studies that estimated incidence by longitudinally re-testing people at risk of infection or by using assays for recent infection. We pooled incidence and relative risk (RR; young [generally defined as ≤25 years] vs older PWID; women vs men) estimates using random-effects meta-analysis and assessed risk of bias with a modified Newcastle-Ottawa scale. This study is registered with PROSPERO, CRD42020220884.

FINDINGS

Our updated search identified 9493 publications, of which 211 were eligible for full-text review. An additional 377 full-text records from our existing database and five records identified through cross-referencing were assessed. Including 28 unpublished records, 125 records met the inclusion criteria. We identified 64 estimates of HIV incidence (30 from high-income countries [HICs] and 34 from low-income or middle-income countries [LMICs]) and 66 estimates of HCV incidence (52 from HICs and 14 from LMICs). 41 (64%) of 64 HIV and 42 (64%) of 66 HCV estimates were from single cities rather than being multi-city or nationwide. Estimates were measured over 1987-2021 for HIV and 1992-2021 for HCV. Pooled HIV incidence was 1·7 per 100 person-years (95% CI 1·3-2·3; I2=98·4%) and pooled HCV incidence was 12·1 per 100 person-years (10·0-14·6; I2=97·2%). Young PWID had a greater risk of HIV (RR 1·5, 95% CI 1·2-1·8; I2=66·9%) and HCV (1·5, 1·3-1·8; I2=70·6%) acquisition than older PWID. Women had a greater risk of HIV (RR 1·4, 95% CI 1·1-1·6; I2=55·3%) and HCV (1·2, 1·1-1·3; I2=43·3%) acquisition than men. For both HIV and HCV, the median risk-of-bias score was 6 (IQR 6-7), indicating moderate risk.

INTERPRETATION

Although sparse, available HIV and HCV incidence estimates offer insights into global levels of HIV and HCV transmission among PWID. Intensified efforts are needed to keep track of the HIV and HCV epidemics among PWID and to expand access to age-appropriate and gender-appropriate prevention services that serve young PWID and women who inject drugs.

FUNDING

Canadian Institutes of Health Research, Fonds de recherche du Québec-Santé, Canadian Network on Hepatitis C, UK National Institute for Health and Care Research, and WHO.

High-Risk Injection-Related Practices Associated with anti-HCV Positivity among Young Adults Seeking Services in Three Small Cities in Wisconsin

BACKGROUND

Hepatitis C virus (HCV) infection has been increasing among people who inject drugs (PWID), younger than 30 years, and living in rural or suburban areas. We examined injection-related behaviors of young PWID to determine factors associated with HCV infection.

METHODS

From September 2013-May 2015, respondent-driven and snowball sampling were used in 3 suburban areas of Wisconsin to recruit PWID 18-29 years who reported injection drug use in the previous 12 months. Participants were tested for HCV antibody (anti-HCV) and reported injection-related behaviors/practices via self-administered computer-based survey. We calculated anti-HCV prevalence and assessed associated factors using multivariable logistic regression.

RESULTS

Forty-two percent (117/280) of participants were male, 83% (231/280) were white, and median age was 23 years. Overall HCV prevalence was 33%, but HCV prevalence among males was 39%. Adjusting for age, sex, race/ethnicity, education, relationship status, insurance status and income, anti-HCV positivity was associated with higher injection frequency (> 100 times in the past six months) (aOR = 3.07; 95% Confidence Interval (95% CI): 1.72-5.45), ever shared syringes (aOR = 5.15; 95% CI: 2.52-10.51), past week/last use receptive rinse water sharing (aOR = 1.88; 95% CI: 1.06-3.33), past week/last use receptive filter sharing (aOR = 3.25; 95% CI: 1.61-6.54), reusing syringes (aOR = 1.91, 95% CI: 1.08-3.37), history of overdose (aOR = 8.82; 95% CI: 2.26-3.95), and having ever injected another PWID (aOR = 8.82; 95%CI 3.94-19.76).

DISCUSSION

Anti-HCV positivity is associated with high-risk injection practices. Young PWID would benefit from access to evidence-based interventions that reduce their risk of infection, link those infected to HCV treatment, and provide education to reduce further transmission.

Novel Routes of Potential Hepatitis C Virus Transmission among People Who Inject Drugs: Secondary Blood Exposures Related to Injection Drug Use

BACKGROUND

The US is in the midst of a national Hepatitis C Virus (HCV) epidemic that appears to be driven by new cases among people who inject drugs (PWID). While HCV transmission among PWID is believed to occur mostly through direct sharing of syringes, some infections may be spread via secondary processes and materials involved in injecting.

OBJECTIVES

Here, we present the prevalence of secondary blood exposures on clothing and nearby surfaces after injection episodes and examine the correlations of these exposures to lifetime HCV infection among a targeted sample of 553 PWID in Los Angeles and San Francisco, California in 2016-18.

RESULTS

In multivariate logistic regression models, higher odds of blood on clothing in the last 30 days was significantly (p < 0.05) associated with lifetime positive HCV status, opioids as primary drug, injecting with others, sharing cookers, and receptive syringe sharing. Higher adjusted odds of blood on nearby surfaces in the last 30 days was significantly associated with lifetime positive HCV status, sharing cookers, and receptive syringe sharing. Native American race was associated with significantly lower adjusted odds of both outcome variables. Conclusions/Importance: Results indicate the relevance of physical and social micro-environments to the potential for blood exposures secondary to injection episodes. Individuals with chronic HCV seropositivity are potentially more likely to expose others to blood due to decreases in the blood's ability to clot. This highlights the need for increased HCV testing at harm reduction sites and increased supply of first aid and wound-care materials to help stop potential blood exposures after injection episodes.

Examining Hepatitis, A and B Vaccination, and HBV Reactivation Monitoring During Direct-Acting Antiviral Therapy for Hepatitis C

The objective of this study was to examine Hepatitis A (HAV) and Hepatitis B (HBV) screening, and the risk of HBV reactivation during Hepatitis C (HCV) therapy with direct-acting antivirals (DAAs). A retrospective chart review was performed of patients treated with second generation DAA therapy from January 2014 to September 2016 at the Iowa City VA Healthcare System. In total 409 patients initiated HCV treatment, 308 (75%) and 241 (59%) were HAV and HBV vaccine eligible, respectively. Among those, 24 (8%) received a HAV vaccine, while only 20 (8%) received a HBV vaccine. Of these, 7 patients initiating an immunization in the clinic had record of completing the series. Further, 101 patients had a reactive Hepatitis B core Antibody indicating previous HBV infection, and 3 of these were tested for HBV reactivation during HCV therapy. Overall, the assessment found low rates of HAV and HBV vaccine administration, indicating missed opportunities for preventative care during HCV therapy. With the known risk of HBV reactivation with DAAs, the need for HAV and HBV screening is essential.

The necessity of education and hepatitis B vaccination for young people: A study of high risk behaviour for blood borne viruses in the United Kingdom

Blood borne virus (BBV) infection in adults involved in high risk behaviour is well recognized. There are limited reported data on young people involved in high risk behaviour. A descriptive questionnaire was used to ascertain risk behaviour at the Young People's Substance Misuse Service (Birmingham). Data collection included risk behaviour and serological tests for hepatitis B, C and HIV. Sixty-five of one-hundred three (63%) young people participated; 37/65 male; age range 13.9-18.9 (median 17.4 years). Risk behaviour included 6 intravenous drug, 58 cannabis, and 61 had sexual partners, of whom 52 (85%) engaged in unprotected sex. Sixty-five participants were negative for BBV infection: 9 were HBV immune. HB vaccination was not available at the centre (for <18 year), and all refused referral to their general practitioner for vaccination due to fear of disclosure. The main risk for BBV acquisition was unprotected sex with multiple sexual partners and illicit drug use. Most were unaware of the risks related to high risk behaviour. Effective education programmes of relevant risk factors with HBV vaccination should be implemented during preadolescence. We recommend an integrated service via specialized centres, to work together to improve awareness and increase efforts to vaccinate adolescents at risk for HBV infection.

Interpersonal and structural factors associated with receptive syringe-sharing among a prospective cohort of female sex workers who inject drugs

AIMS

To determine the interpersonal and structural factors associated with receptive syringe sharing (RSS) among female sex workers who inject drugs (FSW-IDU), a group at high risk of HIV/hepatitis C virus (HCV) acquisition.

DESIGN

Sex workers And Police Promoting Health In Risky Environments (SAPPHIRE) study, a prospective cohort study.

SETTING

Baltimore, MD, USA PARTICIPANTS: One hundred and eighty FSW-IDU; mean age = 33 years, 77.1% white and 62.9% in a relationship/married.

MEASUREMENTS

Surveys were conducted between April 2016 and February 2018. The main outcome was recent RSS (past 3 months). In addition to socio-demographic characteristics and drug use behaviors, we assessed factors at the interpersonal level, including injection practices, intimate partner and client drug use and exposure to violence. Structural-level factors included methods of syringe access.

FINDINGS

Nearly all FSW-IDU used heroin (97.1%) or crack cocaine (89.7%). Recent RSS was reported by 18.3%. Syringes were accessed from needle exchange programs (64.6%), pharmacies (29.7%), street sellers (30.3%) or personal networks (29.1%). Some FSW-IDU had clients or intimate partners who injected drugs (26.3 and 26.9%, respectively). Longitudinal factors independently associated with RSS in the multi-level mixed-effects model were recent client violence [adjusted odds ratio (aOR) = 2.17, 95% confidence interval (CI) = 1.09-4.33], having an intimate partner who injected drugs (aOR = 2.18, 95% CI = 0.98-4.85), being injected by others (aOR = 4.95, 95% CI = 2.42-10.10) and obtaining syringes from a street seller (aOR = 1.88, 95% CI = 0.94-3.78) or from a member of their personal network (aOR = 4.43, 95% CI = 2.21-8.90).

CONCLUSIONS

Client violence, intimate partner injection drug use, being injected by others and obtaining syringes from personal connections appear to increase parenteral HIV/HCV risk among female sex workers who inject drugs.

Estimating the prevalence of hepatitis C among intravenous drug users in upper middle income countries: A systematic review and meta-analysis

Aim

This systematic review and meta-analysis characterizes the prevalence of hepatitis C virus (HCV) infection among intravenous drug users (IDUs) in upper middle-income countries.

Methods

Five databases were searched from 1990–2016 for studies that took place in countries with a GDP per capita of $7,000 to $13,000 USD. The data extraction was performed based on information regarding prevalence, sample size, age of participants, duration of intravenous drug use (IDU), recruitment location, dates of data collection, study design, sampling scheme, type of tests used in identifying antibody reactivity to HCV, and the use of confirmatory tests. The synthesis was performed with a random effects model. The Cochrane statistical Q-test was used to evaluate the statistical heterogeneity of the results.

Results

The 33 studies included in the analysis correspond to a sample of seven countries and 23,342 observations. The point prevalence value estimates and confidence intervals of the random effects model were 0.729 and 0.644–0.800, respectively for all seven countries, and were greatest for China (0.633; 0.522–0.732) as compared to Brazil (0.396; 0.249–0.564). Prevalence for Montenegro (0.416; 0.237–0.621) and Malaysia (0.475; 0.177–0.792) appear to be intermediate. Mexico (0.960) and Mauritania (0.973) had only one study with the largest prevalence. A clear association was not observed between age or duration of IDU and prevalence of HCV, but the data from some groups may indicate a possible relationship. The measures of heterogeneity (Q and I2) suggest a high level of heterogeneity in studies conducted at the country level and by groups of countries.

Conclusions

In this systematic review and meta-analysis, we found that the pooled prevalence of HCV was high (0.729) among a group of seven upper middle income countries. However, there was significant variation in the prevalence of HCV observed in China (0.633) and Brazil (0.396).

Hepatitis C: clinical and biological features related to different forms of cocaine use

INTRODUCTION

Hepatitis C virus (HCV) infection is related with several liver diseases such as cirrhosis and hepatocellular carcinomas, leading to more than 0.5 million deaths every year and to a great global burden. It is known that injection drug users show a high prevalence of HCV infection, being considered a risk group for this disease. Cocaine users seem to be in greater risk than other drug users, and several hypotheses for this association are being studied.

AIM

To review data on HCV infection in cocaine users, taking into consideration the relevance of the different routes of drug administration and other risk behaviors.

METHODS

This was a narrative review performed in the main scientific databases.

RESULTS AND CONCLUSION

Data suggest that cocaine use could be associated with HCV infection due to the specificities of cocaine consumption pattern, even in those subjects who do not inject drugs, in addition to other risky behaviors, such as tattooing and unprotected sex. Injectable cocaine users seem to be more susceptible to contamination than users who do not inject drugs. However, evidence is pointing to the possibility of infection by sharing drug paraphernalia other than syringes. Moreover, specific immune system impairments caused by cocaine use are also being linked with HCV infection susceptibility, persistence and increased pathological effects.

Prevalence of hepatitis C virus in young people who inject drugs in four Colombian cities: A cross-sectional study using Respondent Driven Sampling

BACKGROUND

Colombia has a growing population of young people who inject drugs (PWID). Despite the previously reported association of injection drug use with hepatitis c virus (HCV) in other countries, studies on HCV prevalence in PWID in Colombia are lacking. The objective of this study is to determine the prevalence, demographics, and correlations of risky injection behaviours in HCV seropositive PWID in four Colombian cities (Armenia, Bogotá, Cúcuta and Pereira).

METHODS

This was a cross-sectional study carried out between January and June of 2014 that included 918 PWID from four Colombian cities, recruited by Respondent Driven Sampling. A survey was administered to each participant, and blood samples were collected. Binary logistic regression and multivariate analyses for each city were conducted.

RESULTS

Average participant age was 26 years (SD 6.5). Of all participants, 27.3% of PWID were HCV seropositive, of which 52% were 25 years old or younger. In Pereira, increased risk of HCV infection was found for PWID that: had a history of injection drug use of 5 years or more (AOR: 3.0, CI: 1.7-7.8); were between 25 and 28 years of age (AOR: 5.2, CI: 1.0-26.3); had higher injection frequency (AOR: 2.5, CI: 1.4-4.2), and daily use of gifted, sold, or rented needles or syringes (AOR: 4.5, CI: 1.0-7.1). Additionally, in Cucuta, being HIV seropositive appeared to be greatly associated with risk of HCV seropositivity (AOR: 16.9, CI: 3.5-81.5).

CONCLUSION

Although prevalence of HCV in PWID in Colombia is lower than that reported for other countries, the described demographic characteristics and diverse risky injection behaviors on each city, in the context of a young PWID population with a short injection drug use history, should be taken into account in order to guide efforts towards preventing and reducing risk of HCV infection in PWID in Colombia.

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

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

Geographic Differences in Temporal Incidence Trends of Hepatitis C Virus Infection Among People Who Inject Drugs: The InC3 Collaboration

Background.

We determined temporal trends (1985–2011) in hepatitis C virus (HCV) incidence and associated behavioral exposures for people who inject drugs (PWID) from the United States (Boston, Baltimore, and San Francisco), Canada (Montreal), the Netherlands (Amsterdam), and Australia (Sydney and Melbourne).

Methods.

Using population-based cohort data from HCV-negative PWID, we calculated overall and within-city HCV incidence trends, HCV rates by study enrollment period (1985–2011), and temporal trends in exposure behaviors. Poisson regression models estimated trends in HCV incidence over calendar-time. Survival models identified risk factors for HCV incidence across cities and estimated independent effects of city and calendar period on HCV infection risk.

Results.

Among 1391 initially HCV-negative participants followed prospectively (1644.5 person-years of observation [PYO]), 371 HCV incident infections resulted in an overall incidence of 22.6 per 100 PYO (95% confidence interval [CI], 20.4–25.0). Incidence was highest and remained elevated in Baltimore (32.6/100 PYO), San Francisco (24.7/100 PYO), and Montreal (23.5/100 PYO), lowest in Melbourne and Amsterdam (7.5/100 PYO and 13.1/100 PYO, respectively), and moderate (21.4/100 PYO) in Sydney. Higher rates of syringe and equipment sharing and lower prevalence of opioid agonist therapy were associated with HCV incidence in cities with the highest incidence. Risk for infection dropped by 18% for every 3-year increase in calendar-time (adjusted hazard ratio, 0.8 [95% CI, .8–.9]) in the multivariable model.

Conclusions.

Differences in prevention strategies and injecting contexts may explain the ongoing high HCV incidence in these North American cities and emphasize the need for scale-up of opioid agonist therapy and increased coverage of needle and syringe programs in North America.

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.

Gender, Transience, Network Partnerships and Risky Sexual Practices Among Young Persons who Inject Drugs

Persons who inject drugs (PWID) may be at risk of acquiring HIV and sexually transmitted infections (STIs) from risky sexual practices and elevated disease prevalence within their drug injection and sexual networks. We conducted a personal (egocentric) network study of young PWID (aged 18-30) from the Chicago metropolitan area. Logistic regression with generalized estimating equations evaluated associations between individual and network factors and sexual behaviors. Of 162 participants, 116 (71.6 %) were non-Hispanic White and 135 reported on 314 sexual network members. Multiplexity-having network members with overlapping roles as injection and sexual partners-was associated with more condomless vaginal sex (aOR 5.55; 95 % CI 1.62-19.0) and anal sex (aOR 6.79; 95 % CI 2.49-18.5) and less exchange sex among women (aOR 0.12; 95 % CI 0.03-0.40), adjusting for sociodemographic and sexual network characteristics. The contribution of individual and sexual network factors to HIV/STI transmission among young PWID warrants further research.

Higher incidence of HCV in females compared to males who inject drugs: A systematic review and meta-analysis

Women who inject drugs have been shown to have higher incidence of HIV and risk behaviours than men, but there are conflicting reports about hepatitis C virus (HCV) incidence. We systematically reviewed the literature to examine the female-to-male (F:M) HCV incidence in female and male persons who inject drugs (PWID), and also to explore the heterogeneity (i.e. methodological diversity) in these differences. We searched PubMed and EMBASE for studies published between 1989 and March 2015 for research that reported incidence of HCV infection by sex or HCV incidence F:M rate ratio. A total of 28 studies, which enrolled 9325 PWID, were included. The overall pooled HCV incidence rate (per 100 person-years observation) was 20.36 (95% CI: 13.86, 29.90) and 15.20 (95% CI: 10.52, 21.97) in females and males, respectively. F:M ratio was 1.36:1 (95% CI: 1.13, 1.64) with substantial heterogeneity (I-squared=71.6%). The F:M ratio varied by geographic location from 4.0 (95% CI: 1.80, 8.89) in China to 1.17 (95% CI: 0.95, 1.43) in the U.S. In studies which recruited participants from community settings, the F:M ratio was 1.24 (95% CI: 1.03, 1.48), which was lower than that reported in the clinical settings (1.72, 95% CI: 0.86, 3.45). The number of studies included provided sufficient statistical power to detect sex differences in this analysis. Our findings raise questions and concerns regarding sex differences with respect to the risk of HCV. Both behavioural and biological studies are needed to investigate causes and potential mechanisms as well as sex-specific prevention approaches to HCV infection.

The HCV care continuum among people who use drugs: protocol for a systematic review and meta-analysis

INTRODUCTION

The diagnosis, management, and treatment for hepatitis C virus (HCV) infection (the "HCV care continuum") have improved in recent years. People who use drugs (PWUD) have a prevalence of HCV infection from 30 to 70 %, yet rates of testing, engagement in care, and treatment for HCV are disproportionately low compared to other populations. Delineating the progression of PWUD through the steps in the HCV care continuum in the USA is important in informing efforts to improve HCV outcomes among PWUD.

METHODS/DESIGN

Scientific databases will be searched using a comprehensive automated search strategy; gray literature and reference lists will be manually searched. Eligible reports will provide original research data related to the HCV care continuum in the USA including proportions of PWUD engaging in the following discrete steps: screening/testing, engagement in care (including receiving an HCV clinical assessment), treatment initiation and completion, and rates of those with successful HCV treatment. A quality-rating tool will be developed to ascertain the level of bias (including selection bias) in each report, and a quality score will be assigned to each eligible report. A tool adapted from the Pragmatic Explanatory Continuum Indicator Summary-2 instrument will be developed to assess the extent to which an included report reflects an effectiveness or efficacy study design. Pooled estimates and measures of association will be calculated using random effects models, and heterogeneity will be assessed at each stage of data synthesis.

DISCUSSION

Through this review, we hope to quantify the proportion of PWUD at each progressive step and to help identify key individual, social, and structural points of leakage in the HCV care continuum for PWUD. In meeting these objectives, we will identify predictors to progress along the HCV care continuum, which can be used to inform policy to directly improve HCV care for PWUD.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42016034113.

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.

Agent-Based Model Forecasts Aging of the Population of People Who Inject Drugs in Metropolitan Chicago and Changing Prevalence of Hepatitis C Infections

People who inject drugs (PWID) are at high risk for blood-borne pathogens transmitted during the sharing of contaminated injection equipment, particularly hepatitis C virus (HCV). HCV prevalence is influenced by a complex interplay of drug-use behaviors, social networks, and geography, as well as the availability of interventions, such as needle exchange programs. To adequately address this complexity in HCV epidemic forecasting, we have developed a computational model, the Agent-based Pathogen Kinetics model (APK). APK simulates the PWID population in metropolitan Chicago, including the social interactions that result in HCV infection. We used multiple empirical data sources on Chicago PWID to build a spatial distribution of an in silico PWID population and modeled networks among the PWID by considering the geography of the city and its suburbs. APK was validated against 2012 empirical data (the latest available) and shown to agree with network and epidemiological surveys to within 1%. For the period 2010–2020, APK forecasts a decline in HCV prevalence of 0.8% per year from 44(±2)% to 36(±5)%, although some sub-populations would continue to have relatively high prevalence, including Non-Hispanic Blacks, 48(±5)%. The rate of decline will be lowest in Non-Hispanic Whites and we find, in a reversal of historical trends, that incidence among non-Hispanic Whites would exceed incidence among Non-Hispanic Blacks (0.66 per 100 per years vs 0.17 per 100 person years). APK also forecasts an increase in PWID mean age from 35(±1) to 40(±2) with a corresponding increase from 59(±2)% to 80(±6)% in the proportion of the population >30 years old. Our studies highlight the importance of analyzing subpopulations in disease predictions, the utility of computer simulation for analyzing demographic and health trends among PWID and serve as a tool for guiding intervention and prevention strategies in Chicago, and other major cities.

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.

Hepatitis C Virus Disease Progression in People Who Inject Drugs: Protocol for a Systematic Review and Meta-Analysis

Background

Most hepatitis C virus (HCV) infections in the United States occur following non-sterile injection drug use. However, the majority of people who inject drugs (PWID) with chronic HCV are not currently receiving care.

Objective

This paper presents our protocol for the systematic review and meta-analysis of data on the natural history of HCV among PWID and will inform modeling of the impact and cost-effectiveness of HCV management among this population. This study is conducted as part of the HCV Synthesis Project, which is funded to develop recommendations for HCV control strategies in the United States.

Methods

This protocol describes the methods used for a systematic review and meta-analysis of published and unpublished data on the natural history of HCV among PWID including viral clearance, fibrosis progression, and the incidence of compensated cirrhosis (CC), decompensated cirrhosis (DC), hepatocellular carcinoma (HCC), and liver-related mortality.

Results

Final results are anticipated by December 2016.

Conclusions

Methods used for the synthesis of data on disease progression among HCV mono-infected PWID are presented. Data from the systematic review and meta-analysis will be used to inform simulations of the natural history of HCV and to model the effects of prevention and treatment strategies to reduce disease burden and the associated costs to society and individual patients.

High regional variability of HIV, HCV and injecting risks among people who inject drugs in Poland: comparing a cross-sectional bio-behavioural study with case-based surveillance

Background

People who inject drugs (PWID) are an important group at risk of blood borne infections in Poland. However, robust evidence regarding the magnitude of the problem and geographical variation is lacking, while coverage of prevention remains low. We assessed the potential of combining bio-behavioural studies and case-based surveillance of PWID to gain insight into preventive needs in Poland.

Methods

Results of a bio-behavioural human immunodeficiency virus (HIV) and hepatitis C virus (HCV) prevalence study among ever injectors in six regions in Poland were compared with HIV case-based surveillance trends from 2000 to 2012. Logistic regression was used for multivariable analyses in the prevalence study. The case surveillance data were correlated with prevalence data, by region, to determine surveillance validity and identify any recent trends.

Results

HIV seroprevalence (18% overall) differed more than ten-fold across regions (2.4% to 32%), but HCV seroprevalence and the proportion of PWID sharing needles/syringes in the past 12 months were similar, 44% to 68% and 22% to 29%, respectively. In multivariable models accounting for socio-demographic factors, duration of injecting history and needle sharing practices, regional differences were significant for both HIV and HCV seroprevalence with adjusted odds ratios varying up to a factor of 12.6 for HIV and 3.8 for HCV. The number of new cases of HIV diagnosed in each region during the bio-behavioural study period was strongly correlated (r = 0.93) with HIV prevalence. There was an overall decreasing trend in the number of new diagnoses of HIV over time. However, a transient increase in three regions was preceded by a higher proportion of people with short injecting history (≤5 years) and a high prevalence of HCV coinciding with a low prevalence of HIV in the bio-behavioural study.

Conclusions

Bio-behavioural and case-based data were consistent with respect to the regional distribution of HIV and also provided complementary information, with the proportion of new injectors and high HCV prevalence predicting increases in HIV case rates. We identified three regions in Poland that appear to be at increased need for preventive measures. Data point to the need for a stronger investment in harm reduction programmes in Poland.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-015-0828-9) contains supplementary material, which is available to authorized users.

Gender influences on hepatitis C incidence among street youth in a Canadian setting

PURPOSE

Few studies have examined gender-based differences in the risk of hepatitis C virus (HCV) infection among street-involved youth. We compared rates of HCV infection among male and female street-involved youth in a Canadian setting.

METHODS

The At-Risk Youth Study is a prospective cohort of drug-using street-involved youth. Study recruitment and follow-up occurred in Vancouver, Canada, between September 2005 and November 2011. Eligible participants were illicit drug-using youth aged 14-26 years at enrollment, recruited by street-based outreach. We evaluated rates of HCV antibody seroconversion, measured every 6 months during study follow-up, and used Cox proportional hazards regression to compare risk factors for HCV incidence between male and female street youth.

RESULTS

Among 512 HCV-seronegative youth contributing 836 person-years of follow-up, 56 (10.9%) seroconverted to HCV. Among female participants, the incidence density of HCV infection was 10.9 per 100 person-years, and in males, it was 5.1 per 100 person-years (p = .009). In multivariate analyses, female gender was independently associated with a higher rate of HCV seroconversion (adjusted hazard ratio, 2.01; 95% confidence interval, 1.18-3.44). Risk factors were similar in gender-stratified analyses and included heroin injection and crystal methamphetamine injection, although syringe sharing was only associated with HCV incidence among males.

CONCLUSIONS

Among street-involved youth in this setting, females had double the incidence of HCV seroconversion demonstrating the need for gender-focused HCV prevention interventions for this population.

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.

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.

Prescription opioid misuse and its relation to injection drug use and hepatitis C virus infection: protocol for a systematic review and meta-analysis

BACKGROUND

The production, prescription, and consumption of opioid analgesics to treat non-cancer pain have increased dramatically in the USA in the past decade. As a result, misuse of these opioids has increased; overdose and transition to riskier forms of drug use have also emerged. Research points to a trend in transition to drug injection among those misusing prescription opioids, where clusters of acute hepatitis C virus (HCV) infection are now being reported. This systematic review and meta-analysis aims to synthesize the prevalence of prescription opioid misuse in the USA and examine the rate of transition to injection drug use and incident HCV in these new people who inject drugs (PWID).

METHODS/DESIGN

Eligible studies will include quantitative, empirical data including national survey data. Scientific databases will be searched using a comprehensive search strategy; proceedings of scientific conferences, reference lists, and personal communications will also be searched. Quality ratings will be assigned to each eligible report using the Newcastle-Ottawa Scale. Pooled estimates of incidence rates and measures of association will be calculated using random effects models. Heterogeneity will be assessed at each stage of data synthesis.

DISCUSSION

A unique typology of drug use is emerging which is characterized by antecedent prescription opioid misuse among PWID. As the epidemic of prescription opioid misuse matures, this will likely serve as a persistent source of new PWID. Persons who report a recent transition to drug injection are characterized by high rates of HCV seroincidence of 40 per 100 person years or higher. Given the potential for the persistence and escalation of the consequences of prescription opioid misuse in the USA, there is a critical need for synthesis of the current state of the epidemic in order to inform future public health interventions and policy.

SYSTEMATIC REVIEW REGISTRATION

PROSPERO CRD42014008870.

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.

The changing epidemiology of hepatitis C virus infection in the United States: National Health and Nutrition Examination Survey 2001 through 2010

BACKGROUND & AIMS

In light of the dramatically changing hepatitis C therapeutic landscape, knowledge of the current burden of HCV infection in the general population of the United States is critical.

METHODS

The National Health and Nutrition Examination survey collects nationally representative data on HCV infection in the civilian population of the United States. Data from 2001 to 2010 were combined for this study. HCV testing was completed in 38,025 participants.

RESULTS

The prevalence of anti-HCV in the United Sates decreased from 1.9% (95% CI 1.5%-2.5%) in 2001-2002 to 1.3% (95% CI 0.9%-1.8%) in 2005-2006, and remained stable up to 2010. About 67% of all infected persons were positive for HCV RNA, indicating 2.3 million people with chronic HCV infection, of whom 68% have genotype 1. Seventy percent of infected persons were born between 1945 and 1965, with prevalence of 3.5% (95% CI 2.2%-4.8%). The stable rate since 2006 is mostly related to prevalent cases and foreign born persons migrating into US. Other important risk factors include less education and low economic status. Race, HIV status, number of sexual partners, and blood transfusions are no longer associated with HCV infection.

CONCLUSIONS

As of 2010, approximately 2.3 million persons were chronically infected with Hepatitis C in the US. Most of those infected are prevalent, rather than incident cases. The prevalence of HCV was on the decline, but has stabilized since 2006. Future studies should explore reasons for no decline in HCV prevalence since 2006.

Transitions from injecting to non-injecting drug use: potential protection against HCV infection

Transitions from injecting to non-injecting drug use have been reported from many different areas, particularly in areas with large human immunodeficiency virus (HIV) epidemics. The extent to which such transitions actually protect against HIV and HCV has not been determined. A cross-sectional survey with HIV and hepatitis C (HCV) testing was conducted with 322 former injectors (persons who had injected illicit drugs but permanently transitioned to non-injecting use) and 801 current injectors recruited in New York City between 2007 and 2012. There were no differences in HIV prevalence, while HCV prevalence was significantly lower among former injectors compared to current injectors. Years injecting functioned as a mediating variable linking former injector status to lower HCV prevalence. Transitions have continued well beyond the reduction in the threat of AIDS to injectors in the city. New interventions to support transitions to non-injecting drug use should be developed and supported by both drug treatment and syringe exchange programs.

A randomized trial of a hepatitis care coordination model in methadone maintenance treatment

OBJECTIVES

We evaluated the efficacy of a hepatitis care coordination intervention to improve linkage to hepatitis A virus (HAV) and hepatitis B virus (HBV) vaccination and clinical evaluation of hepatitis C virus (HCV) infection among methadone maintenance patients.

METHODS

We conducted a randomized controlled trial of 489 participants from methadone maintenance treatment programs in San Francisco, California, and New York City from February 2008 through June 2011. We randomized participants to a control arm (n = 245) and an intervention arm (n = 244), which included on-site screening, motivational-enhanced education and counseling, on-site vaccination, and case management services.

RESULTS

Compared with the control group, intervention group participants were significantly more likely (odds ratio [OR] = 41.8; 95% confidence interval [CI] = 19.4, 90.0) to receive their first vaccine dose within 30 days and to receive an HCV evaluation within 6 months (OR = 4.10; 95% CI = 2.35, 7.17). A combined intervention adherence outcome that measured adherence to HAV-HBV vaccination, HCV evaluation, or both strongly favored the intervention group (OR = 8.70; 95% CI = 5.56, 13.61).

CONCLUSIONS

Hepatitis care coordination was efficacious in increasing adherence to HAV-HBV vaccination and HCV clinical evaluation among methadone patients.

HCV infection prevalence lower than expected among 18-40-year-old injection drug users in San Diego, CA

San Diego, California shares the world's busiest land border crossing with Tijuana, Mexico-a city where 95 % of injection drug users (IDUs) test hepatitis C virus (HCV) antibody-positive. Yet, little is known about the prevalence and risk behaviors for HCV among IDUs in San Diego. In 2009-2010, 18-40-year-old IDUs in San Diego County completed a risk assessment interview and serologic testing for HCV and HIV infection. Recruitment involved respondent-driven sampling, venue-based sampling at a syringe exchange program, and convenience sampling. Correlates of HCV infection were identified by multivariable logistic regression. Among 510 current IDUs, 26.9 % (95 % CI 23.0-30.7 %) and 4.2 % (95 % CI 2.4-5.9 %) had been infected with HCV and HIV, respectively. Overall, median age was 28 years; 74 % were male; 60 % white and 29 % Hispanic; and 96 % were born in the U.S. Median years of injecting was 6; 41 % injected daily; 60 % injected heroin most often; 49 % receptively shared syringes and 68 % shared other injection paraphernalia; and only 22 % reported always using new syringes in the past 3 months. Two thirds had ever traveled to Mexico and 19 % injected in Mexico. HCV infection was independently associated with sharing injection paraphernalia (adjusted odds ratio [AOR] = 1.69) and SEP use (AOR = 2.17) in the previous 3 months, lifetime history of drug overdose (AOR = 2.66), and increased years of injecting (AOR = 2.82, all P values <0.05). Controlling for recruitment method did not alter results. HCV infection prevalence among IDUs in San Diego was modest compared to other US cities and much lower than Tijuana. Given that known individual-level HCV risk factors were common in San Diego, the city's lower HCV prevalence might be due to differences in social and structural factors between the cities.

Injecting risk behavior among traveling young injection drug users: travel partner and city characteristics

Young injection drug users (IDUs), a highly mobile population, engage in high levels of injecting risk behavior, yet little is understood about how such risk behavior may vary by the characteristics of the cities to which they travel, including the existence of a syringe exchange program (SEP), as well as travel partner characteristics. In 2004-2005, we conducted a 6-month prospective study to investigate the risk behavior of 89 young IDUs as they traveled, with detailed information gathered about 350 city visits. In multivariable analyses, travel to larger urban cities with a population of 500,000-1,000,000 was significantly associated with injecting drugs (adjusted odds ratio (AOR) = 3.71; 95 % confidence interval (CI), 1.56-8.82), ancillary equipment sharing (AES; AOR = 7.05; 95 % CI, 2.25-22.06) and receptive needle sharing (RNS; AOR = 5.73; 95 % CI, 1.11-27.95), as compared with visits to smaller cities with populations below 50,000. Region of the country, and the existence of a SEP within the city visited, were not independently associated with injecting drugs, AES, or RNS during city visits. Traveling with more than one injecting partner was associated with injecting drugs during city visits (AOR = 2.77; 95 % CI, 1.46-5.27), when compared with traveling alone. Additionally, both non-daily and daily/almost daily alcohol use during city visits were associated with AES (AOR = 3.37; 95 % CI, 1.42-7.68; AOR = 3.03; 95 % CI, 1.32-6.97, respectively) as compared with no alcohol consumption. Traveling young IDUs are more likely to inject when traveling with other IDUs and to engage in higher risk injection behavior when they are in large cities. Risk behavior occurring in city visits, including equipment sharing and alcohol consumption, suggests further need for focused interventions to reduce risk for viral infection among this population.

The epidemiology of chronic hepatitis C and one-time hepatitis C virus testing of persons born during 1945 to 1965 in the United States

Hepatitis C virus (HCV) is the most common blood-borne infection in the United States. HCV infection is a leading cause of chronic liver disease, end-stage liver disease, and liver transplantation. Newly available therapies can clear HCV in most infected persons who receive treatment. However, many persons living with HCV infection are unaware of their infection status, including those born during 1945-1965 (a population at increased risk for chronic hepatitis C in the United States). This review highlights the epidemiology of hepatitis C and the importance of HCV testing and linkage to care in an era of more effective antiviral therapies.

Gender differences in hepatitis C seroprevalence and suboptimal vaccination and hepatology services uptake amongst substance misusers

Injecting drug users are the principal at risk group for blood borne viruses. The aim was to assess the feasibility of screening substance misusers for blood borne viruses, and to offer appropriate vaccinations/referral to hepatology services. This was a nurse led prospective 6-month study based at a large Substance Misuse Service in south east England. Of the 196 consecutive individuals assessed, 81 were eligible for HBV immunization of whom only 33.3% completed a vaccination course. Prevalence of positive serological markers were: anti-HBc 14.4%, HBsAg 1.5%, and HCV antibody 37.9%. Compared to men, women were more likely to accept blood borne virus testing (83.3% vs. 62.3%), have ever injected (89.6% vs. 76.3%), overdose (54.2% vs. 23.6%), be anti-HBc positive (27.5% vs. 8.8%), drink alcohol above national recommended guidelines (41.7% vs. 25.7%), and have a positive HCV serology (55% vs. 30.4%) (P ≤ 0.05 for all). Of the 73 individuals identified with a positive HBsAg and or HCV antibody, only 14 (19.1%) were known to hepatology services and 8 (20%) of those eligible subsequently accepted a specialist referral. In conclusion, serological markers for blood borne viruses remain high in substance misusers (anti-HBc 14.4%, HCV antibody 37.9%), with women more likely to be positive. Overall, only 33.3% and 20%, respectively, complete HBV vaccination and accept a hepatology referral. A multidisciplinary approach is paramount to address both the blood borne viruses and the substance misuse and realignment of hepatitis services to Substance Misuse Services may offer such a strategy.

Respondent driven sampling and community structure in a population of injecting drug users, Bristol, UK

BACKGROUND

A 2006 respondent driven sampling (RDS) survey of injecting drug users (IDUs) in Bristol, UK, estimated 40 per 100 person years HCV incidence but in 2009 another RDS survey estimated only 10 per 100 person years incidence amongst the same population. Estimated increases in intervention exposure do not fully explain the decrease in risk. We investigate whether the underlying contact network structure and differences in the structure of the RDS trees could have contributed to the apparent change in incidence.

METHOD

We analyse the samples for evidence that individuals recruit participants who are like themselves (assortative recruiting). Using an assortativity measure, we develop a Monte Carlo approach to determine whether the RDS data exhibit significantly more assortativity than is expected for that sample. Motivated by these findings, a network model is used to investigate how much assortativity and the structure of the RDS tree impacts sample estimates of prevalence and incidence.

RESULTS

The samples suggest there is some assortativity on injecting habits or markers of injecting risk. The 2009 sample has lower assortativity than 2006. Simulations of RDS confirm that assortativity influences the estimated incidence in a population and the structure of RDS samples can result in bias. Our simulations suggest that RDS incidence estimates have considerable variance, making them difficult to use for monitoring trends.

CONCLUSIONS

We suggest there was likely to have been a decline in risk between 2006 and 2009 due to increased intervention coverage, but the bias and variance in the estimates prevents accurate estimation of the incidence.

Centers for Disease Control and Prevention initiatives to prevent hepatitis C virus infection: a selective update

Hepatitis C virus (HCV) infection is a complex public health problem, characterized by a high prevalence of chronic infection, an increasing burden of HCV-associated disease, low rates of testing and treatment, and the prospect of increasing incidence associated with the epidemic of injection drug use. Three-quarters of chronic HCV infections occur among persons born from 1945 through 1965. Prevention efforts are complicated by limited knowledge among health care professionals, persons at risk and in the public at large. At the Centers for Disease Control and Prevention, efforts to improve primary and secondary prevention effectiveness center on policy development, education and training initiatives, and applied research. This report provides a brief overview of some of these efforts, including the development of testing recommendations for the 1945-1965 birth cohort, research and evaluation studies in settings where persons who inject drugs receive services, and a national viral hepatitis education campaign that targets health care professionals, the public, and persons at risk.

HCV and HIV infection among heroin addicts in methadone maintenance treatment (MMT) and not in MMT in Changsha and Wuhan, China

OBJECTIVE

To compare HCV and HIV infection among heroin addicts in MMT and not in MMT in two large cities in central China.

METHODS

A total of 541 heroin addicts were recruited from MMT clinics and voluntary detoxification centers in Changsha and Wuhan, China. Structured questionnaires collected data on their socio-demographics, clinical status, risk behaviors, and their knowledge of HIV. Their HIV serostatus and Hepatitis C virus (HCV) serostatus were determined by testing antibodies in blood serum.

RESULTS

We observed a higher prevalence of HCV infection among MMT heroin addicts (82.3%) than that in the non-MMT group (50.6%). However, our findings indicated that the heroin addicts in MMT had less drug or sexual HIV/HCV risk behaviors and more knowledge about HIV than non-MMT addicts. The heroin addicts in MMT had a significantly higher percentage of individuals who always used condoms (44.9%) compared with patients in the non-MMT group (14.6%, p = 0.039), and they had more knowledge about HIV than non-MMT individuals (p<.001). The percentage of HIV-positive addicts in the MMT group (0.7%) and non-MMT group (0.8%) were almost same.

CONCLUSION

Our study indicated that the rate of HCV infection among heroin addicts among MMT or non-MMT settings in central China is very high. The non-MMT heroin addicts have higher risk of becoming infected with HCV in the future, while at present they have lower rates of HCV infection than MMT heroin addicts. Although rates of HIV infection among MMT and non-MMT heroin addicts are low now, they are all at great risk of becoming infected with HIV in the future, especially for non-MMT heroin addicts. We should use the MMT sites as a platform to improve the control of HCV and HIV infection in heroin addicts.

Behavior and major barriers faced by non-injectable drug users with HBV/HCV seeking treatment for hepatitis and drug addiction in Rio de Janeiro, Brazil

Drug users (DU) are a marginalized group and at risk for viral hepatitis, who seldom access health services. A cross-sectional survey was conducted with 111 DU with chronic HBV/HCV and 15 in-depth interviews with health professionals/policymakers in Rio de Janeiro, Brazil. Most interviewees were male, non-white, with a low educational background, unemployed and/or living on less than $245 a month (minimun wage). In the last 6 months, 61.8% of interviewees snorted cocaine, 64.7% at least once a week. Half of the interviewees had a stable partner and 38.3% of those with occasional partners never/almost never using condoms. Addiction treatment seeking was found to be associated with: being white (OR:5.5), high-school degree (OR:8.7), and employment (OR:5.7). Hepatitis treatment seeking was high (80.9%), and access to low-threshold, user-friendly health services was key for treatment seeking behaviors (OR:3.6). Missed opportunities for hepatitis treatment seem to be associated with structural (uneven political/financial support to hepatitis programs) and patient-related barriers (severe addiction and non-adherence). Those most in need were less likely to access treatment, calling for renewed strategies, in order to curb hepatitis among impoverished drug users and their sexual partners.

Extent of illicit drug use and dependence, and their contribution to the global burden of disease

This paper summarises data for the prevalence, correlates, and probable adverse health consequences of problem use of amphetamines, cannabis, cocaine, and opioids. We discuss findings from systematic reviews of the prevalence of illicit drug use and dependence, remission from dependence, and mortality in illicit drug users, and evidence for acute and chronic effects of illicit drug use. We outline the regional and global distribution of use and estimated health burden from illicit drugs. These distributions are likely to be underestimates because they have not included all adverse outcomes of drug use and exclude those of cannabis--the mostly widely used illicit drug. In high-income countries, illicit drug use contributes less to the burden of disease than does tobacco but a substantial proportion of that due to alcohol. The major adverse health effects of cannabis use are dependence and probably psychotic disorders and other mental disorders. The health-related harms of cannabis use differ from those of amphetamine, cocaine, and opioid use, in that cannabis contributes little to mortality. Intelligent policy responses to drug problems need better data for the prevalence of different types of illicit drug use and the harms that their use causes globally. This need is especially urgent in high-income countries with substantial rates of illicit drug use and in low-income and middle-income countries close to illicit drug production areas.

Can intranasal drug use reduce HCV infection among injecting drug users?

BACKGROUND

Preventing HCV infection among people who inject drugs is a difficult public health challenge. We examined the potential role of intranasal drug use in reducing HCV acquisition.

METHODS

Subjects were recruited from IDUs entering the Beth Israel drug detoxification program from 2005 to 2010. A structured interview was administered and serum samples were collected for HCV testing.

RESULTS

726 active injecting drug users were recruited from 2005 to 2010. HCV prevalence was 71%, 90% reported recent heroin injection and 44% reported recent intranasal heroin use. In a multiple logistic regression analysis, being HCV seropositive was associated with more years injecting, Latino ethnicity, previous testing for HCV, and recent injection of speedball, and negatively associated with recent intranasal use of heroin (AOR=0.52, 95% CI 0.33-0.82) and intranasal use of speedball (AOR=0.41, 95% CI 0.31-0.80). The association between intranasal heroin use and lower HCV seroprevalance was observed among both new injectors and persons with long injecting histories (16+ years since first injection).

CONCLUSION

Encouraging intranasal use as an alternative to injection among persons currently injecting drugs may be a viable strategy for reducing HCV transmission.

Saúde pública, redução de danos e a prevenção das infecções de transmissão sexual e sanguínea: revisão dos principais conceitos e sua implementação no Brasil

Este artigo aborda o contexto histórico e o marco conceitual da implantação dos programas de redução de danos no campo da saúde pública, com ênfase nos programas brasileiros. A presente revisão teve como objetivo principal investigar a pertinência atual de tais programas no enfrentamento das infecções de transmissão sexual e sanguínea, em especial, a AIDS e a hepatite C. Os resultados sistematizados pela literatura nacional e internacional indicam que as ações práticas de redução de danos são mais efetivas quando integradas a outras medidas de saúde pública, guiadas por princípios em comum. Iniciativas de redução de danos afinadas com princípios de saúde pública não se prendem a modelos, nem se esgotam em cuidados de saúde propriamente ditos. Abrangem diversas modalidades de ações pragmáticas, com base em políticas públicas, devem estar em sintonia com a comunidade desde seu planejamento, e serem executadas em parceria com esta.

The increasing mortality burden of liver disease among opioid-dependent people: cohort study

AIMS

Hepatitis C (HCV) infection is highly prevalent among injection drug users (IDUs) and likely to cause significant mortality over time, but little research attention has focused upon the magnitude of this risk, particularly among ageing users. This study examined trends over time in mortality attributed to liver disease, and in particular contrasting this with other more commonly studied causes of death [acquired immune deficiency syndrome (AIDS), suicide and overdose] among an ageing cohort of heroin-dependent people in Australia.

DESIGN

Data linkage study of methadone treatment entrants with the National Deaths Index.

SETTING

 A cohort entering methadone treatment for heroin dependence in New South Wales, Australia, 1980-85.

PARTICIPANTS

  A total of 2489 people entering methadone treatment for heroin dependence and 54,847 person-years (PY) of follow-up.

MEASUREMENTS

  Linkage of data on all methadone entrants between 1980 and 1985 with data from the Australian National Deaths Index, linked using probabilistic record linkage software.

FINDINGS

There were 8.2 deaths per 1000 PY [95% confidence interval (CI) 7.5-9.0], with standardized mortality ratios (SMRs) of 4.6 (95% CI 4.2-5.0). Almost one in five (17%) of deaths were from underlying liver-related causes, most commonly viral hepatitis. The overall mortality rate for any liver cause was 1.4 deaths per 1000 PY (95% CI 1.1-1.7), 17 times higher than to the general population (95% CI 13.4-21.3), with relative elevations more marked for females (SMR 27.9; 95% CI 17.7-41.9) than males (SMR 14.5; 95% CI 10.8-19.0). Liver mortality increased over time, becoming the most common cause of death by the end of follow-up.

CONCLUSIONS

  Liver disease has become the most common cause of mortality among ageing opioid-dependent people in an ageing Australian cohort. There is an imperative to reduce the long-term risks of HCV and other risks to the liver, including alcohol consumption, which are typically not the major clinical focus for this group.

Potential role of safer injection facilities in reducing HIV and hepatitis C infections and overdose mortality in the United States

BACKGROUND

Safer injection facilities (SIFs) reduce risks associated with injecting drugs, particularly public injection and overdose mortality. They exist in many countries, but do not exist in the United States. We assessed several ethical, operational, and public health considerations for establishing SIFs in the United States.

METHOD

We used the six-factor Kass framework (goals, effectiveness, concerns, minimization of concerns, fair implementation, and balancing of benefits and concerns), summarized needs of persons who inject drugs in the United States, and reviewed global evidence for SIFs.

RESULTS

SIFs offer a hygienic environment to inject drugs, provide sterile injection equipment at time of injection, and allow for safe disposal of used equipment. Injection of pre-obtained drugs, purchased by persons who inject drugs, happens in a facility where trained personnel provide on-site counseling and referral to addiction treatment and health care and intervene in overdose emergency situations. SIFs provide positive health benefits (reducing transmission of HIV and viral hepatitis, bacterial infections, and overdose mortality) without evidence for negative health or social consequences. SIFs serve most-at-risk persons, including those who inject in public or inject frequently, and those who do not use other public health programs. It is critical to address legal, ethical, and local concerns, develop and implement relevant policies and procedures, and assess individual- and community-level needs and benefits of SIFs given local epidemiologic data.

CONCLUSIONS

SIFs have the potential to reduce viral and bacterial infections and overdose mortality among those who engage in high-risk injection behaviors by offering unique public health services that are complementary to other interventions.

The impact of needle and syringe provision and opiate substitution therapy on the incidence of hepatitis C virus in injecting drug users: pooling of UK evidence

AIMS

To investigate whether opiate substitution therapy (OST) and needle and syringe programmes (NSP) can reduce hepatitis C virus (HCV) transmission among injecting drug users (IDUs).

DESIGN

Meta-analysis and pooled analysis, with logistic regression allowing adjustment for gender, injecting duration, crack injecting and homelessness.

SETTING

Six UK sites (Birmingham, Bristol, Glasgow, Leeds, London and Wales), community recruitment.

PARTICIPANTS

A total of 2986 IDUs surveyed during 2001-09.

MEASUREMENT

Questionnaire responses were used to define intervention categories for OST (on OST or not) and high NSP coverage (≥100% versus <100% needles per injection). The primary outcome was new HCV infection, measured as antibody seroconversion at follow-up or HCV antibody-negative/RNA-positive result in cross-sectional surveys.

FINDINGS

Preliminary meta-analysis showed little evidence of heterogeneity between the studies on the effects of OST (I2=48%, P=0.09) and NSP (I2=0%, P=0.75), allowing data pooling. The analysis of both interventions included 919 subjects with 40 new HCV infections. Both receiving OST and high NSP coverage were associated with a reduction in new HCV infection [adjusted odds ratios (AORs)=0.41, 95% confidence interval (CI): 0.21-0.82 and 0.48, 95% CI: 0.25-0.93, respectively]. Full harm reduction (on OST plus high NSP coverage) reduced the odds of new HCV infection by nearly 80% (AOR=0.21, 95% CI: 0.08-0.52). Full harm reduction was associated with a reduction in self-reported needle sharing by 48% (AOR 0.52, 95% CI: 0.32-0.83) and mean injecting frequency by 20.8 injections per month (95% CI: -27.3 to -14.4).

CONCLUSIONS

There is good evidence that uptake of opiate substitution therapy and high coverage of needle and syringe programmes can substantially reduce the risk of hepatitis C virus transmission among injecting drug users. Research is now required on whether the scaling-up of intervention exposure can reduce and limit hepatitis C virus prevalence in this population.

The effects of widespread methadone treatment on the molecular epidemiology of hepatitis C virus infection among injection drug users in Hong Kong

The distribution of HCV genotypes among injection drug users in Hong Kong was assessed in context of methadone treatment availability. Three time periods were defined by the year of initiating injection-on or before 1980, 1981-1994, and 1995-2006-with methadone becoming widely available since the second period. Of the 273 HCV RNA-positive cases, the most prevalent subtype was HCV 6a (52.4%), followed by HCV 1b (38.5%). The new variants of HCV subtypes 6e and 6h were detected. Both subtypes 1b and 6a were prevalent among older injectors, while subtype 3a was more common in young injectors and those initiating injection recently during the third time period. Age (P < 0.05) and recent injection frequency (P < 0.01) were independently associated with HCV 6a infection. Subtype 1b was predominant in the first period, whereas 6a was more common in the second and third. Subtype 1b sequences appeared to have originated at two positions on the phylogenetic tree, while 6a showed a more disperse distribution suggestive of multiple introductions. Phylogenetic analysis on the NS5B region did not reveal specific clustering of any subtype/genotype. Overall, there was no suggestion of outbreaks of HCV. The extensive use of methadone may have protected Hong Kong from the emergence of HCV clusters among injection drug users.

Gender-specific situational correlates of syringe sharing during a single injection episode

Factors associated with syringe sharing differ between women and men; however, it is uncertain whether these hold within the setting of a single injection episode. A questionnaire eliciting information about the last injection episode with others present was administered to participants in a cohort of Montréal injection drug users (IDUs). Logistic regression was used to identify correlates of syringe sharing and to test potential gender differences in relation to syringe sharing. Data from 467 participants revealed significant differences between men and women with regard to situational factors; however, the relationships between situational factors and syringe sharing did not vary according to gender. In multivariate models including both genders, syringe sharing was associated with various attributes of other IDUs who were present as well as alcohol use during that specific episode. These results highlight the relevance of situational factors in injection drug use activity, regardless of gender.

Hepatitis C treatment eligibility and comorbid medical illness in methadone maintenance (MMT) and non-MMT patients: a case-control study

Comorbid medical illness is common in patients with chronic hepatitis C (HCV) infection and in methadone treatment (MMT) patients, yet little is known about the impact of medical illness on HCV treatment eligibility. Medical illness and HCV treatment eligibility were compared in a case-control study of 80 MMT patients entering an HCV treatment trial and 80 matched non-MMT patients entering HCV treatment in a gastroenterology clinic. 91% of MMT and 85% of non-MMT patients had chronic medical conditions. Despite similar medical severity ratings, a significantly higher proportion (77%) of non-MMT patients were eligible for HCV treatment than were MMT patients (56%) (p<.01). Specific comorbid medical and psychiatric illness led to ineligibility in only 18% of MMT and 16% of non-MMT patients. However, failure to complete the medical evaluation process was significantly (p<.001) more likely to cause ineligibility among MMT patients (19%) than non-MMT patients (0%).

Prevalence and correlates of former injection drug use among young noninjecting heroin users in Chicago

Noninjecting heroin users (NIHU) that were 16-30 years old were street recruited in Chicago between 2002 and 2005 to examine factors associated with having ever injected. Participants completed computerized self-administered interviews and provided specimens for HIV and hepatitis serotesting. Of 689 NIHU, 51.2% were non-Hispanic Black, 64.4% were male, and the median age was 25 years. Former injection was reported by 17.9%; of those, 66.7% injected <10 times. Multivariable analysis identified individual and social factors that place young NIHU at increased risk of injection. Targeted interventions are necessary to prevent transitions to injection and reduce transmission of HIV and viral hepatitis infections. The study's limitations are noted.

Gender differences in hepatitis C antibody prevalence and risk behaviours amongst people who inject drugs in Australia 1998-2008

BACKGROUND

Global prevalence of hepatitis C virus (HCV) is estimated to be around 3% with approximately 170 million people affected. In Australia, and in many other resource rich countries, injecting drug use is the single most important risk factor for acquiring HCV, with around a third of diagnoses occurring in women. This study aims to assess gender differences in hepatitis C antibody prevalence and associated risk behaviours amongst a large sample of PWID in Australia.

METHODS

During a one to two week period in October, PWID attending selected NSP sites are invited to participate in the Australian NSP Survey. Between 1998 and 2008, approximately 16,000 individuals completed a self-administered questionnaire and provided a capillary blood sample for HIV and HCV antibody testing. We stratified our sample by time since onset of injecting and analysed the demographic characteristics, injecting behaviours and antibody test results to determine gender differences.

RESULTS

Women were found to be at increased risk of exposure to hepatitis C in all duration of injection categories except those injecting for 17 or more years. In the early years of injecting, women also reported higher rates of receptive sharing of needles and syringe and ancillary equipment when compared to men. Last injecting heroin, methadone or buprenorphine was significantly associated with HCV antibody prevalence amongst both males and females injecting for less than 5 years.

CONCLUSION

Findings indicate that women are at greater risk than men of HCV infection during the early years of injection through higher rates of receptive sharing of needles and syringes and/or ancillary equipment. Our results suggest that women who are new to injecting, and Indigenous women in particular, should be identified as priority populations when developing and implementing harm reduction strategies that target people who inject illicit drugs.