Injecting Drug Users Population Research Articles

The influence of hepatitis C and alcohol on liver‐related morbidity and mortality in Glasgow’s injecting drug user population

Infection with the hepatitis C virus (HCV) is associated with the development of severe liver disease, but cofactors--namely alcohol abuse--in Scotland's HCV-positive population complicate estimation of the unique contribution of HCV. We compared the risk of hospital admission/death for a liver-related cause in a large cohort of Glasgow's injecting drug users (IDUs) testing HCV-positive with IDUs testing HCV negative. Data for 6566 current/former IDUs who had been tested for anti-HCV and/or HCV RNA by polymerase chain reaction in Greater Glasgow health board between 1993 and 2007 were linked to the national hospitalization database and deaths registry to identify all admissions and deaths from a liver-related condition. Relative risks were estimated using Cox proportional hazards regression for recurrent events. Time at risk was censored at 2 years following an HCV test to address bias owing to unobserved seroconversion. The risk of hospitalization/death from a liver-related or an alcoholic liver-related condition following HCV testing was greater for those IDUs with no prior alcohol-related hospitalization who tested positive [adjusted hazard ratio (HR) = 3.2, 95% CI: 1.5-6.7; 4.9, 95% CI: 1.8-13.1, respectively], compared with those who tested anti-HCV negative, but not for those IDUs with a prior alcohol admission (HR = 0.8, 95% CI: 0.4-1.5; 0.8, 95% CI: 0.4-1.6). There was little evidence for an increased risk of hospitalization/death for an exclusively nonalcoholic liver condition for those testing positive (HR = 1.5, 95% CI: 0.8-2.7), after adjustment for previous alcohol-related admission. Within Glasgow's IDU population, HCV positivity is associated with an increased risk of a liver-related outcome, but this is not observed for those IDUs whose problem alcohol use already increases their risk.

Can antiviral therapy for hepatitis C reduce the prevalence of HCV among injecting drug user populations? A modeling analysis of its prevention utility

Hepatitis C virus antiviral treatment is effective for individual patients but few active injecting drug users are treated. We considered the utility of antiviral treatment for primary prevention of hepatitis C. A hepatitis C transmission model among injecting drug users was developed, incorporating treatment (62.5% average sustained viral response) with no retreatment after initial treatment failure, potential re-infection for those cured, equal genotype setting (genotype 1:genotype 2/3), and no immunity. In addition, we examined scenarios with varied treatment response rates, immunity, or retreatment of treatment failures. In the baseline scenario, annually treating 10 infections per 1000 injecting drug users results in a relative decrease in hepatitis C prevalence over 10 years of 31%, 13%, or 7% for baseline (untreated endemic chronic infection) prevalences of 20%, 40%, or 60%, respectively. Sensitivity analyses show that including the potential for immunity has minimal effect on the predictions; prevalence reductions remain even if SVR is assumed to be 25% lower among active IDU than current evidence suggests; retreatment of treatment failures does not alter the short-term (<5 years) projections, but does increase treatment gains within 20 years; hepatitis C free life years gained from treating active injecting drug users are projected to be higher than from treating non-injecting drug users for prevalences below 60%. Despite the possibility of re-infection, modest rates of hepatitis C treatment among active injecting drug users could effectively reduce transmission. Evaluating and extending strategies to treat hepatitis C among active injectors are warranted.

P70 Can antiviral therapy for hepatitis C reduce the prevalence of HCV among injecting drug user populations? A modelling analysis of its prevention utility

IntroductionHCV antiviral treatment (peginterferon and ribavirin) is effective for individual patients, but few active injecting drug users (IDUs) are treated.AimWe considered the utility of antiviral treatment for reducing HCV transmission...

HIV and Proteinuria in an Injection Drug User Population

Proteinuria is a major determinant of chronic kidney disease. We aimed to characterize the prevalence and correlates of proteinuria in a cohort of HIV-infected and uninfected injection drug users. A cross-sectional analysis was performed among 902 injection drug users (273 HIV-infected) in the AIDS Linked to the Intravenous Experience cohort. The primary outcome was proteinuria defined as having a urine protein/creatinine concentration ratio >200 mg/g. Poisson regression with robust variance was used to determine prevalence ratios. Overall, 24.8% of participants had proteinuria; the prevalence was 2.9 times higher among HIV-infected participants (45%) compared with HIV-uninfected participants (16%). In addition, age, health insurance, employment status, hepatitis B and C serostatus, diabetes, and high BP were associated with proteinuria. Neither antiretroviral therapy nor features of illicit drug use history were associated with proteinuria. In multivariate analysis, HIV infection, unemployment, increased age, diabetes, hepatitis C infection, and high BP were significantly associated with a higher prevalence of proteinuria. In an aging, predominantly African-American cohort of injection drug users, we found a striking burden of proteinuria that was strongly associated with HIV status. In addition to being a pathway to ESRD, proteinuria is a potent risk factor for cardiovascular morbidity and mortality. Evaluation of aggressive screening and disease-modification strategies in this high-risk population is warranted.

Modeling the effect of high dead‐space syringes on the human immunodeficiency virus (HIV) epidemic among injecting drug users

To illustrate the impact of different proportions of injecting drug users (IDUs) sharing high dead-space syringes (HDSS) or low dead-space syringes (LDSS) on the probability of human immunodeficiency virus (HIV) transmission; and thus the impact on injection-related HIV prevalence and incidence. A stochastic mathematical model was used to evaluate the impact of HDSS use in high- and low-risk IDU populations. Model parameters were obtained from peer-reviewed publications. Analytical solutions of a simplified deterministic model were obtained to explain the effect of HDSS on HIV endemic states. Simulation analysis shows that the HIV epidemic could be sustained even when a small percentage of sharing (10%) involved HDSS. The effect is much stronger in high-risk compared with low-risk populations. Steady state HIV prevalence increases with the proportion of HDSS, and for high- and low-risk populations reaches around 80% and 20%, respectively. For low-risk populations, the use of LDSS could result in the virtual elimination of HIV. These results are dependent upon an evidence-supported assumption of a significant difference in HIV transmission risk associated with HDSS versus LDSS. Our models suggest that injection-related HIV epidemics may not occur when most (e.g. 95% or more) IDUs use LDSS. While these results are based on indirect risk measures and a number of simplifying assumptions, the effect of blood retained in high dead-space syringes on HIV prevalence seems to be very strong, even using relatively conservative assumptions. The findings have potential implications for needle exchange programs and the types of syringes produced and distributed world-wide.

Seroprevalence of Blood-borne Infections and Population Sizes Estimates in a Population of Injecting Drug Users in Croatia

Similar to some other Central European countries, Croatia has low HIV prevalence among injecting drug users (IDUs) but high hepatitis C (HCV) prevalence. This may indicate different patterns of risk behaviour in this region than in other parts of Europe. The main objectives of this study were to assess the seroprevalence of HIV and hepatitis B and C and related risk factors among IDUs in the three largest Croatian cities (Zagreb, Split, Rijeka) and within the national prison system, as well as to apply a multiplier-method population size estimation of IDUs in Zagreb, Split and Rijeka. Recruitment sites were selected in collaboration with the local public health institutes, NGOs, Centers for treatment municipalities and the judiciary system. Participants were recruited during September and October 2007. Trained peer-recruiters were used to recruit IDU participants at treatment and harm reduction centres as well as pre-identified social, commercial and street based venues. Participants completed the study questionnaire and provided venous blood samples for HIV, hepatitis B and hepatitis C testing. The study included 601 participants, of whom 121 were recruited in Split, 130 in Zagreb, 150 in Rijeka and 200 in the prison system. The prevalence of positive anti-HCV tests was 65% in Split, 51% in Zagreb, 29% in Rijeka and 44% in the prisons. The prevalence of anti-HBcAg was 31% in Split, 13% in Zagreb, 9% in Rijeka and 24% in prison. No case of HIV infection was found. The estimated IDUs population sizes were 2,805 for Zagreb area, 3,347 for Split and 1,370 for Rijeka area, however confidence intervals were very large, indicating the need for larger samples. A high frequency of positive markers on hepatitis B virus and C virus in the population of injecting drug users in Croatia has been confirmed with this research, as well as a low prevalence of HIV infection. This may be related to relatively low levels of injecting risk behaviour and injecting frequency although it is not possible to make strong conclusions on risk behaviour, as participants were mostly recruited in harm reduction programmes. This research should be followed by targeted activities for reducing risks of infectious diseases among injecting drug users in the Republic of Croatia and future research at the national level.

Déterminants psychosociaux d’utilisateurs de drogues d’utiliser une seringue neuve

Background A limited number of injection drug users are hard to reach through needle-exchange programs. They obtain their injection material from drug-using peers. This dependence on others can make them more at risk of contracting HIV through sharing non-sterile syringes. The aim of this study is to identify determinants of the intention to systematically resort to use of a new syringe by injection drug users rarely or never involved in needle-exchange programs in Quebec. Methods A cross-sectional survey was conducted in Québec city by means of a questionnaire measuring variables from the theory of planned behavior and past behavior. Participants ( n = 97) were recruited by acquaintances who kept regular contacts with the local needle-exchange programs. Multiple linear regression was used to identify the psychosocial determinants of the intention, and beliefs underlying those determinants were identified using multiple logistic regression. Results Half of participants reported using a new syringe for each injection in the last month. In multivariate analyses, this past behavior together with theory of planned behavior constructs explained 70% of the variation in participants intent to use a new syringe for each injection (control beliefs: β = 0.39; past behavior: β = 0.27; attitude: β = 0.21; perceived behavioral control: β = 0.20; subjective norm: β = 0.12). In logistic regression, six important beliefs were identified. Conclusion This study resulted in the development of a predictive model of intention to use always a new syringe for each injection among a population of injection drug users in Quebec. Study results could serve as the foundation for the development of interventions to promote this behavior.

Optimal targeting of Hepatitis C virus treatment among injecting drug users to those not enrolled in methadone maintenance programs

Background This work used mathematical modelling to explore effective policy for Hepatitis C virus (HCV) treatment in Australia in the context of methadone maintenance treatment (MMT). Method We consider two models to depict HCV in the population of injecting drug users (IDU) within Australia. The first model considers the IDU population as a whole. The second model includes separate components for those that are or are not enrolled in MMT. The impact of different levels of HCV treatment and its allocation dependent on MMT status were then determined in terms of the steady state levels of each of these models. Results Although increasing levels of HCV treatment decrease chronic infection prevalence, initially numbers of acutely infected can rise. This is caused by the high rate of reinfection. We find that no matter the extent of HCV treatment, HCV prevalence cannot be eliminated without limiting risk behaviour. Assuming equal adherence to HCV therapy between MMT and non-MMT, over 84% of HCV treatment should be allocated to those not in MMT. Only if adherence to HCV therapy in non-MMT patients falls below 44% of that in MMT then treatment should be preferentially directed to those in MMT. Conclusions Contrary to generally held beliefs regarding HCV treatment the majority of therapy should be allocated to those that are still actively injecting. This is due to rates of reinfection and to the high turnover of individuals in MMT. Higher adherence to HCV therapy in MMT would need to be achieved before this changed.

Effects of duration of injection drug use and age at first injection on HCV among IDU in Kabul, Afghanistan

Hepatitis C virus (HCV) prevalence is high among injection drug users (IDUs) in Afghanistan. Duration of injection and young age at first injection are common risk factors for HCV in IDU populations. The association of HCV with these time factors was analyzed. Socio-demographic and drug use behavior information were collected. Participants had rapid testing for HCV with recombinant immunoblot assay confirmation. Modeling of non-linear associations was performed using fractional polynomial logistic regression. Among 459 male IDUs, age at first injection had a constant HCV risk (odds ratio (OR): 1.01 per year; 95% confidence interval (CI): 0.98-1.03), while each additional year of injection drug use had a significantly increased risk (OR: 4.72 per year, 95% CI: 2.92-7.66). HCV risk increased significantly with each additional year of injecting drug use by groups of injectors: young (< or =22 years, OR: 1.97; 95% CI: 1.27-3.07), middle (23-28 years, OR: 1.76; 95% CI: 1.28-2.43) and older (> or =29 years, OR: 7.56; 95% CI: 3.15-18.14). The probability of HCV infection increased markedly by duration of injection drug use and varied according to age at first injection. Drug counseling and educational efforts should be directed to older drug users who have not yet initiated injecting and to young IDUs to avert infection and reduce risky drug use behaviors.

Comparison of injection drug users accessing syringes from pharmacies, syringe exchange programs, and other syringe sources to inform targeted HIV prevention and intervention strategies

ObjectiveTo describe injection drug users (IDUs) who access syringes through different outlets to help inform the prevention needs of IDUs who underuse safe syringe sources in New York City (NYC), where syringe availability is high compared with other U.S. cities. DesignCross sectional. SettingNYC, 2005–2007. Participants285 IDUs. InterventionParticipants were recruited using random street-intercept sampling in 36 socioeconomically disadvantaged neighborhoods. Main outcome measuresIDUs using syringe exchange programs (SEPs), pharmacies, or other outlets as a primary syringe source were compared based on sociodemographic characteristics, injection practices, and medical service use. ResultsChi-square tests and polytomous logistic regression were used to compare IDUs with different self-reported primary syringe sources used in the 6 months preceding study entry. Compared with IDUs using other syringe sources, those primarily using SEPs were less likely to be black (adjusted odds ratio 0.26 [95% CI 0.11–0.57]), more likely to inject daily (3.32 [1.58–6.98]), and more likely to inject with a new syringe (2.68 [1.30–5.54]). Compared with IDUs using other syringe sources, those primarily using pharmacies were less likely to be black (0.39 [0.17–0.90]). ConclusionThese data suggest that pharmacies and SEPs may be reaching different populations of IDUs and highlight a subpopulation of highly marginalized IDUs (i.e., black race, infrequent injectors) who are underusing safe syringe sources in NYC. Targeted interventions are needed to reduce racial disparities and increase use of safe syringe outlets.

Heterosexual HIV and Sexual Partnerships Between Injection Drug Users and Noninjection Drug Users

Sex partnerships with injection drug users (IDU) are an understudied network-level risk factor for heterosexual HIV infection. Heterosexuals with no history of injection were recruited from high-risk areas in New York City through respondent-driven sampling. We examined the prevalence of IDU sex partnerships among these non-IDU, the factors associated with having a past year IDU partner, and the independent association of HIV infection and IDU sex partnerships in multiple logistic regression. Of the 601 non-IDU in this analysis, 13.8% had a sex partner in the past year with a history of injection. IDU partnerships were significantly more common among women and those with higher levels of unprotected sex and drug and alcohol use. Overall, 7.0% tested positive for HIV. HIV prevalence was higher (p = 0.07) for participants with IDU partners (9.6%) compared to those with no IDU partners (4.6%). In multiple logistic regression, participants with IDU partners were over twice as likely to be HIV-infected (p = 0.08). Sex partnerships with IDU were common and may play an important role in heterosexual HIV transmission in areas with large IDU populations. Prevention interventions to encourage the disclosure of injection history and risk reduction specifically for those with IDU partners are indicated.

HIV prevention, treatment, and care services for people who inject drugs: a systematic review of global, regional, and national coverage

Previous reviews have examined the existence of HIV prevention, treatment, and care services for injecting drug users (IDUs) worldwide, but they did not quantify the scale of coverage. We undertook a systematic review to estimate national, regional, and global coverage of HIV services in IDUs. We did a systematic search of peer-reviewed (Medline, BioMed Central), internet, and grey-literature databases for data published in 2004 or later. A multistage process of data requests and verification was undertaken, involving UN agencies and national experts. National data were obtained for the extent of provision of the following core interventions for IDUs: needle and syringe programmes (NSPs), opioid substitution therapy (OST) and other drug treatment, HIV testing and counselling, antiretroviral therapy (ART), and condom programmes. We calculated national, regional, and global coverage of NSPs, OST, and ART on the basis of available estimates of IDU population sizes. By 2009, NSPs had been implemented in 82 countries and OST in 70 countries; both interventions were available in 66 countries. Regional and national coverage varied substantially. Australasia (202 needle-syringes per IDU per year) had by far the greatest rate of needle-syringe distribution; Latin America and the Caribbean (0.3 needle-syringes per IDU per year), Middle East and north Africa (0.5 needle-syringes per IDU per year), and sub-Saharan Africa (0.1 needle-syringes per IDU per year) had the lowest rates. OST coverage varied from less than or equal to one recipient per 100 IDUs in central Asia, Latin America, and sub-Saharan Africa, to very high levels in western Europe (61 recipients per 100 IDUs). The number of IDUs receiving ART varied from less than one per 100 HIV-positive IDUs (Chile, Kenya, Pakistan, Russia, and Uzbekistan) to more than 100 per 100 HIV-positive IDUs in six European countries. Worldwide, an estimated two needle-syringes (range 1-4) were distributed per IDU per month, there were eight recipients (6-12) of OST per 100 IDUs, and four IDUs (range 2-18) received ART per 100 HIV-positive IDUs. Worldwide coverage of HIV prevention, treatment, and care services in IDU populations is very low. There is an urgent need to improve coverage of these services in this at-risk population. UN Office on Drugs and Crime; Australian National Drug and Alcohol Research Centre, University of New South Wales; and Australian National Health and Medical Research Council.

Increased risk for hepatitis C associated with solvent use among Canadian Aboriginal injection drug users

BackgroundSolvent abuse is a particularly serious issue affecting Aboriginal people. Here we examine the association between solvent use and socio-demographic variables, drug-related risk factors, and pathogen prevalence in Aboriginal injection drug users (IDU) in Manitoba, Canada.MethodsData originated from a cross-sectional survey of IDU from December 2003 to September 2004. Associations between solvent use and variables of interest were assessed by multiple logistic regression.ResultsA total of 266 Aboriginal IDU were included in the analysis of which 44 self-reported recent solvent use. Hepatitis C infection was 81% in solvent-users, compared to 55% in those reporting no solvent use. In multivariable models, solvent-users were younger and more likely to be infected with hepatitis C (AOR: 3.5; 95%CI: 1.3,14.7), to have shared needles in the last six months (AOR: 2.6; 95%CI:1.0,6.8), and to have injected talwin & Ritalin (AOR: 10.0; 95%CI: 3.8,26.3).InterpretationHigh hepatitis C prevalence, even after controlling for risky injection practices, suggests that solvent users may form closed networks of higher risk even amongst an already high-risk IDU population. Understanding the social-epidemiological context of initiation and maintenance of solvent use is necessary to address the inherent inequalities encountered by this subpopulation of substance users, and may inform prevention strategies for other marginalized populations.

Estimating The Level of HIV Prevention Coverage, Knowledge and Protective Behavior Among Injecting Drug Users: What Does The 2008 UNGASS Reporting Round Tell Us?

The 2001 Declaration of Commitment from the United Nations General Assembly Special Session on HIV/AIDS (UNGASS) set the prevention of HIV infection among injecting drug users (IDUs) as an important priority in the global fight against HIV/AIDS. This article examines data gathered to monitor the fulfillment of this commitment in low-income and middle-income countries (LMICs) where resources to develop an effective response to HIV are limited and where injecting drug use is reported to occur in 99 (of 147) countries, home to 75% of the estimated 15.9 million global IDU population. Data relating to injecting drug use submitted by LMICs to the Joint United Nations Programme on HIV/AIDS (UNAIDS) in the 2008 reporting round for monitoring the Declaration of Commitment on HIV/AIDS were reviewed. The quality of the data reported was assessed and country data were aggregated and compared to determine progress in HIV prevention efforts. For each indicator, the mean value weighted for the size of each country's IDU population was determined; regional estimates were also made. Reporting was inconsistent between countries. Forty percent of LMIC (40/99), where injecting occurs, reported data for 1 or more of the 5 indicators pertinent to HIV prevention among IDUs. Many of the data reported were excluded from this analysis because the indicators used by countries were not consistent with those defined by UNAIDS Monitoring and Evaluation Reference Group and could not be compared. Data from 32 of 99 countries met our inclusion criteria. These 32 countries account for approximately two-thirds (68%) of the total estimated IDU population in all LMICs.The IDU population weighted means are as follows: 36% of IDUs tested for HIV in the last year; 26% of IDUs reached with HIV prevention programs in the last year; 45% of IDUs with correct HIV prevention knowledge; 37% of IDUs used a condom at last sexual intercourse; and 63% of IDUs used a clean syringe at last injection. Marked variance was observed in the data reported between different regions. Data from the 2008 United Nations General Assembly Special Session reporting round provide a baseline against which future progress might be measured. The data indicate a wide variation in HIV service coverage for IDUs and a wide divergence in HIV knowledge and risk behaviors among IDUs in different countries. Countries should be encouraged and assisted in monitoring and reporting on HIV prevention for IDUs.

Molecular epidemiological survey on HIV-1 among the injecting drug users population in Shenzhen

To study the prevalent status of human immunodeficiency virus-1 (HIV-1) subtypes in IDU (injecting drug users) population in Shenzhen and to study their source of infection in order to predict the epidemic trend and evolution. 166 HIV-1 positive plasma from the IDUs was collected from 1996 to 2008. HIV-1 env genes were amplified by nested-PCR from RNA. The C2-V3 regions (450 bp) of HIV-1 env were sequenced for analyses. Phylogenetic analyses were performed on the nucleotide sequence data. Among 166 samples, there were 6 HIV-1 strains including CRF01_AE, CRF08_BC, CRF07_BC 3 circulating recombinant forms (CRFs) and B', C, A1 3 subtypes. Data from the genotype analyses showed that 65.06% (108/166) were CRF01_AE, 19.88% (33/166) were CRF07_BC, 6.02% (10/166) were CRF08_BC, 7.23% (9/166) were subtype B', 0.60% (1/166) were subtype C and 1.20% (2/166) were subtype A1. Phylogenetic tree analysis showed that some of HIV-1 clusters defined in CRF01_AE, CRF07_BC and subtype B' in different time groups. Significant increase of gene distance in CRF01_AE and CRF07_BC strains in the three different periods. CRF01_AE and CRF07_BC were the major epidemic CRF strains among the IDU population in Shenzhen while the subtype B', C, A1 and CRF08_BC were also circulating in IDU population in this region. The variation of all different subtypes was increasing through these years.

Prevalence and Correlates of Hepatitis C Infection among Male Injection Drug Users in Detention, Tehran, Iran

For the benefit of planning for the future care and treatment of people infected with hepatitis C virus (HCV) and to help guide prevention and control programs, data are needed on HCV seroprevalence and associated risk factors. We conducted a cross-sectional sero-behavioral survey of injection drug users (IDU) detained for mandatory rehabilitation during a police sweep of Tehran, Iran, in early 2006. During the study period, a consecutive sample comprising 454 of 499 (91.0%) men arrested and determined to be IDU by urine test and physical examination consented to a face-to-face interview and blood collection for HCV antibody testing. Overall, HCV prevalence was 80.0% (95% confidence interval (CI) 76.2–83.6). Factors independently associated with HCV infection included history of incarceration (adjusted OR 4.35, 95% CI 1.88–10.08), age of first injection ≤25 years (OR 2.72, 95% CI 1.09–6.82), and history of tattooing (OR 2.33, 95% CI 1.05–5.17). HCV prevalence in this population of IDU upon intake to jail was extremely high and possibly approaching saturation. Findings support that incarceration is contributing to the increased spread of HCV infection in Iran and calls for urgent increased availability of HCV treatment, long-term preparation for the care of complications of chronic infection, and rapid scale-up of programs for the primary prevention of parenterally transmitted infections among drug users.

Diagnosis of hepatitis C virus infection in Scotland's injecting drug user population

We estimated the extent of undiagnosed hepatitis C virus (HCV) infection in injecting drug users (IDUs) in Scotland. We used record-linkage to determine HCV diagnosis status for 41 062 current/former IDUs attending drug treatment and support services between 1 April 1995 and 31 March 2006; the extent of undiagnosed HCV infection was estimated by comparing the number HCV-diagnosed to the number HCV-infected (estimated from an unlinked anonymous testing survey of 2141 current/former IDUs). In all, 9145 IDUs (22%) were diagnosed HCV antibody-positive since first attendance at drug services (diagnosis rate of 33.6/1000 person-years, 95% CI 32.7-34.4). By 31 March 2006, of the 19 632 current/former IDUs who had attended drug services and were determined to be living with HCV, an estimated 58% (95% CI 45-62) had not been HCV-diagnosed. It is essential that the deployment of resources for identifying at-risk IDUs with a view to offering antiviral therapy is guided by evidence.

Seroepidemiology of human herpesvirus 8 (HHV-8) infection in injecting drug users

A cross-sectional study was carried out in injecting drug users (IDUs) from Greece to assess the seroprevalence of human herpesvirus 8 (HHV-8) and to identify potentially associated risk factors. A total of 288 IDUs were tested for K8.1 antibodies to HHV-8 lytic antigen. Associations between HHV-8 serostatus and potential risk factors were examined using univariate and multivariate logistic regression analysis. Seroprevalence of HHV-8 was 24.3% (95% CI 19.5-29.7), increasing with age from 19.4% in those aged <30 years to 52.9% in those aged 40 years (P for trend=0.003). No statistically significant associations between HHV-8-positive status and gender, educational level, age at first drug injection, needle sharing, number of imprisonments, complications from drug overdose, HIV and HCV were observed. In the multivariate logistic regression analysis, older age (40 vs. <40 years, OR 3.30, 95% CI 1.14-9.56) and report of septicaemia/abscess (yes vs. no, OR 1.80, 95% CI 1.01-3.18) were each independently associated with higher HHV-8 seroprevalence. HHV-8 is highly prevalent in the IDU population in Greece. The independent association between HHV-8 and reported abscess or septicaemia supports the hypothesis that poor hygiene conditions in the setting of drug injection may contribute to HHV-8 transmission.

Never injected, but hepatitis C virus‐infected: a study among self‐declared never‐injecting drug users from the Amsterdam Cohort Studies

The aim of this study was to gain insight in transmission routes of hepatitis C virus (HCV) infection among never-injecting drug users (DU) by studying, incidence, prevalence, determinants and molecular epidemiology of HCV infection. From the Amsterdam Cohort Studies among DU, 352 never-injecting DU were longitudinally tested for HCV antibodies. Logistic regression was used to identify factors associated with antibody prevalence. Part of HCV NS5B was sequenced to determine HCV genotype and for phylogenetic analyses, in which sequences were compared with those from injecting DU. HCV antibody prevalence was 6.3% and HCV incidence was 0.49/1000 PY. HIV-positive status, female sex and starting injection drug use during follow-up (a putative marker of past injection drug use), were independently associated with HCV prevalence. The main genotypes found were genotype 3a (50%) and 1a (30%). Phylogenetic analysis revealed that HCV strains in never-injecting DU did not cluster together and did not differ from HCV strains circulating in injecting DU. We found a higher HCV prevalence in never-injecting DU than in the general population. Phylogenetic analysis shows a strong link with the injecting DU population. The increased risk could be related to underreporting of injecting drug use or to household or sexual transmission from injectors to noninjectors. Our findings stress the need for HCV testing of DU who report never injecting, especially given the potential to treat HCV infection effectively.

Distribution of CCR5 genotypes and HLA Class I B alleles in HIV-1 infected and uninfected injecting drug users from Rio de Janeiro, Brazil

Host genetic factors play an important role in the HIV epidemic dynamics, and have been considered in studies assessing susceptibility/resistance to HIV-1 infection as well as clinical evolution. Class I and Class II HLA alleles have been associated with the heterogeneity of HIV-1 infection susceptibility, as protective or risk factors for HIV-1 transmission. Moreover, a 32-base pair deletion in the HIV-1 CCR5 gene-coding region confers resistance to HIV-1 infection in homozygous individuals for the deleted allele. In this study, DNA samples from HIV-1 infected and uninfected injecting drug users (IDUs) from Rio de Janeiro were PCR amplified to determine CCR5 genotypes based on the presence of the CCR5Δ32 mutation and typed for the HLA-B locus, in an attempt to assess possible associations between these genetic factors and susceptibility/resistance to HIV-1 infection. The distribution of CCR5 genotypes between the two IDU groups did not differ. The homozygous mutant genotype Δ32/Δ32 was not found in this study. Except for HLA-B*45 (4.0% vs. 3.0%; p = 0.04) and for B*51 (12.1% vs. 4.4%; p = 0.002), no statistically significant differences were made evident when analyzing the frequencies of each HLA-B allele between Caucasian and non-Caucasian IDUs. The most frequent HLA-B alleles were B*15; B*35; B*44 and B*51. Although some differences in the allele frequencies could be observed between the two IDU groups, none of these was statistically significant. Therefore, no putative association between these genetic markers and susceptibility/resistance to HIV-1 infection could be made evident in the present study. So far, the assessment of genetic markers among the IDU population has been restricted to North American, European, and Asian studies and this report represents a pioneer descriptive study of the distribution of CCR5 genotypes and HLA-B alleles in Rio de Janeiro, Brazil.