HIV prevalence and risk behaviours among injecting drug users in six indonesian cities implications for future HIV prevention programs

ABSTRACT: BACKGROUND: The HIV prevalence among injecting drug users (IDUs) in Indonesia reached 50% in 2005. While drug use remains illegal in Indonesia, a needle and syringe program (NSP) was implemented in 2006. METHODS: In 2007, an integrated behavioural and biological surveillance survey was conducted among IDUs in six cities. IDUs were selected via time-location sampling and respondent-driven sampling. A questionnaire was administered face-to-face. IDUs from four cities were tested for HIV, syphilis, gonorrhoea and chlamydia. Factors associated with HIV were assessed using generalized estimating equations. Risk for sexual transmission of HIV was assessed among HIV-positive IDUs. RESULTS: Among 1,404 IDUs, 70% were daily injectors and 31% reported sharing needles in the past week. Most (76%) IDUs received injecting equipment from NSP in the prior week; 26% always carried a needle and those who didn't, feared police arrest. STI prevalence was low (8%). HIV prevalence was 52%; 27% among IDUs injecting less than 1 year, 35% among those injecting for 1-3 years compared to 61% in long term injectors (p < 0.001). IDUs injecting for less than 3 years were more likely to have used clean needles in the past week compared to long term injectors (p < 0.001). HIV-positive status was associated with duration of injecting, ever been imprisoned and injecting in public parks. Among HIV-infected IDUs, consistent condom use last week with steady, casual and commercial sex partners was reported by 13%, 24% and 32%, respectively. CONCLUSIONS: Although NSP uptake has possibly reduced HIV transmission among injectors with shorter injection history, the prevalence of HIV among IDUs in Indonesia remains unacceptably high. Condom use is insufficient, which advocates for strengthening prevention of sexual transmission alongside harm reduction programs.     

Hepatitis B and hepatitis C seroprevalence and risk behaviour among community-recruited drug injectors in North West Wales

We estimated the prevalence of markers of hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, and injecting risk behaviour, among community-recruited injecting drug users (IDUs) in North West Wales in 2001 and 2002. Sample collection was undertaken by trained current and former IDUs. Oral fluid samples (n = 153) were tested as part of the Unlinked Anonymous Prevalence Monitoring Programme ongoing survey of IDUs. Approximately 12% of the sample reported that they were currently in a drug treatment programme. Of the 153 samples screened 27% (95% CI 20%-34%, 41/153) were anti-HBc positive, and 23% (95% CI 16%-30%, 35/153) were anti-HCV positive. Sixteen per cent (95% CI 10%-22%, 25/ 153) of the samples were positive for both anti-HBc and anti-HCV. Of the subjects 15% (95% CI 9%-20%) knew they had been vaccinated against hepatitis B. Direct sharing of needles and syringes in the 28 days prior to interview was reported by 44% (95% CI 35%-54%), and sharing of any equipment including that used for drug preparation prior to injection was reported by 66% (95% CI 57%-76%). In North West Wales, syringe sharing is a common practice, and a high proportion of IDUs have been exposed to bloodborne viruses. Hepatitis B vaccination coverage within this population appears to be low and needs to be increased. Further efforts are needed to improve the availability of clean injecting equipment.     

Service uptake and characteristics of injection drug users utilizing North America's first medically supervised safer injecting facility

In 2003, the city of Vancouver, British Columbia, opened North America’s first government-sanctioned safer injecting facility, where injection drug users (IDUs) can inject preobtained illicit drugs under the supervision of nurses. Use of the service by IDUs was followed by measurable reductions in public drug use and syringe sharing. IDUs who are frequently using the program tend to be high-intensity cocaine and heroin injectors and homeless individuals.

The facility has provided high-risk IDUs a hygienic space where syringe sharing can be eliminated and the risk of fatal overdose reduced. Ongoing evaluation will be required to assess its impact on overdose rates and HIV infection levels, as well as its ability to improve IDU contact with medical care and addiction treatment

     

新旧注射吸毒人群HIV传播因素研究

目的探讨和分析新旧注射吸毒者的人口学特征及HIV传播因素,为预防控制艾滋病流行提供科学依据。方法选取针具交换点和戒毒所新旧人群为研究对象,采用面对面问卷调查,问卷内容包括新旧人群的人口学特征、艾滋病相关知识、干预服务参号隋况、高危行为学特征及HIV传播影响因素。应用SPSS16．0软件进行统计分析。结果共调查474例注射吸毒者,其中新人群（注射吸毒≤5年）及旧人群（注射吸毒〉5年）分别为157例（33．1％）和317例（66．9％）。调查对象的HIV感染率为20．5％,HIV感染率与吸毒年限呈正相关趋势（_=0．83,P=0．004）,且在5年内的变化速率最快。多因素Logistic回归模型结果显示,在〈30岁的新人群中,男性、重复使用及共用针具是HIV传播的影响因素;在30～40岁的旧人群中,男性、知晓共用注射辅助材料的危害及共用针具是HIV传播的影响因素;在〉40岁的旧人群中,男性、文化程度初中及以上、参加过针具交换及共用针具是HIV传播的影响因素。结论加强对新旧人群的宣传教育力度,倡导针具交换、有套性交、扩大干预服务覆盖面,知而信、信而行,是预防控制HIV传播与流行的有效措施。     

Prevalence and incidence of bloodborne viral infections among Danish prisoners

In order to determine the prevalence and incidence of bloodborne viral infections among prisoners, we conducted a prospective study in a Danish medium security prison for males. The prisoners were offered an interview and blood test for hepatitis and human immunodeficiency virus HIV at inclusion as well as at release from prison or end of study. Of 403 prisoners available 325 (79%) participated in the initial survey and for 142 (44%) a follow-up test was available. 43% (140/325) of the participants were injecting drug users (IDUs) of whom 64% were positive for hepatitis B (HBV) and 87% for hepatitis C (HCV) markers. No cases of HIV or human T lymphotropic virus (HTLV) were found. 32% of all prisoners could transmit HBV and/or HCV by blood contact. 70% of IDUs had shared injecting equipment, and 60% had injected inside prison. Only 2% of IDUs were vaccinated against HBV. Duration of injecting drug use, numbers of imprisonments, and injecting in prison were independently and positively associated with the presence of HBV antibodies among IDUs by logistic regression analysis. The HBV incidence was 16/100 PY (95% CI: 2–56/100 PY) and the HCV incidence 25/100 PY (1–140) among injecting drug users (IDUs). We conclude that IDUs in prison have an incidence of hepatitis B and C 100 times higher than reported in the general Danish population. They should be vaccinated against hepatitis B and new initiatives to stop sharing of injecting equipment in and outside prison is urgently needed.     

Modelling the impact on Hepatitis C transmission of reducing syringe sharing: London case study

BACKGROUND: Hepatitis C virus (HCV) prevalence and incidence among injecting drug users (IDUs) has increased in London and rest of UK. To inform public health action, mathematical modelling is used to explore the possible impact of strategies to decrease syringe sharing. METHODS: A mathematical model was developed to simulate HCV transmission amongst IDUs in London. Because of parameter uncertainty, numerical search algorithms were used to obtain different model fits to HCV seroprevalence data from London for 2002-03. These simulations were used to explore the likely impact of HCV prevention activities that reduce syringe sharing amongst all IDUs, IDUs that have injected for greater than one year, or IDUs with lower or higher frequencies of syringe sharing. RESULTS: Key differences between model fits centred on how they simulated the high HCV incidence amongst new injectors, either through assuming increased HCV infectivity during acute infection, a large sub-group of high frequency syringe sharers, or increased sharing among new IDUs. Despite parameter uncertainty, the model projections suggest that modest reductions in syringe sharing frequency (<25%) will reduce the HCV seroprevalence in newly initiated IDUs (injecting less than four years) but much larger and sustained reductions (>50%) are required to reduce the HCV seroprevalence in long-term IDUs (injecting more than 8 years). Critically the model also suggested that large reductions in HCV seroprevalence will be achieved only if interventions target all IDUs and reach IDUs within 12 months of injecting. DISCUSSION: Public health interventions must reduce syringe sharing amongst all IDUs, including newly initiated IDUs, and be sustained for many years to reduce HCV infection. More accurate data on key behavioural (sharing frequency) and biological (percentage of infected IDUs that clear infection) parameters is required to improve model projections.     

云南省部分静脉吸毒者使用别人用过的注射器的情况及影响因素的累积比数模型分析

[目的]探讨静脉吸毒人员使用别人用过的注射器情况及影响因素，为有关部门控制艾滋病提供理论依据。[方法]2003--2004年，在云南省4个县（市）随机抽取968名吸毒人员进行调查，并进行多因素累积比数模型分析。[结果]968名静脉吸毒人员中，最近1个月使用别人用过的注射器的占37．5％，8．3％的经常使用。累积比数模型分析结果，文化程度高、静脉吸毒的时间长、年龄大、认为“看上去健康的人不会是HIV感染者”的吸毒者。经常使用别人用过的注射器的OR值分别为1．030、0．996，0．395、1．467；上述选人变量与偶尔使用和没有使用无统计学意义。[结论]部分静脉吸毒人员倬用别人用1寸的注射器，年龄小、文化程度高、吸毒时间短和缺乏艾滋病知识者经常使用别人用过的注射器。     

Erratum to: The Prevalence of HIV, HBV, HCV, and HIV-Related Risk-Taking Behaviors among Palestinian Injecting Drug Users in the East Jerusalem Governorate

The objective of the study was to determine HIV, HBV, HCV seroprevalence and to assess HIV risks among Palestinian injecting drug users (IDUs) in the East Jerusalem Governorate. Following formative research, a bio-behavioral survey using respondent-driven sampling was carried out in 2010 among 199 IDUs aged 19-56 years (M = 41.33, SD = 8.09). Venous blood was drawn for biological testing. Data on drug abuse and sexual behaviors were collected by face-to-face interviewing. No HIV + cases were found. Five participants were infected with Hepatitis B and 84 participants (estimated population proportion of 40.3 %) tested positive for Hepatitis C. A great majority of the surveyed IDUs (90.4 %) reported using sterile injecting equipment the last time they injected. In a multivariate assessment, age (OR = 2.52, p < .05), education (OR = 6.67, p < .01), personal network size (OR = .18, p < .001), and the frequency of drug injecting in the past month (OR = .20, p < .001) were associated with using sterile injecting equipment in the past week. Condom use at most recent sexual intercourse was reported by about a third (34.2 %) of IDUs. The study documented substantial exposure to HIV risks among Palestinian IDUs whose vulnerability is inseparable from sociopolitic and socioeconomic characteristics of their social environment.     

Analysis of a Targeted Intervention Programme on the Risk Behaviours of Injecting Drug Users in India: Evidence From the National Integrated Biological and Behavioural Surveillance Survey

ObjectivesThis study provides insights on the impact of a targeted intervention (TI) programme on behaviour change among injecting drug users (IDUs) in India.MethodsThis paper examined the data from the Integrated Biological and Behavioural Surveillance 2014–2015 for IDUs in India. Logistic regression was performed to understand the factors (TI programme services) that affected injecting risk behaviours by adjusting for covariates. Propensity score matching was conducted to understand the impact of the TI programme on using new needles/syringes and sharing needles/syringes in the most recent injecting episode by accounting for the covariates that predicted receiving the intervention.ResultsParticipants who received new needles and syringes from peer educators or outreach workers were 1.3 times (adjusted odds ratio, 1.29; 95% confidence interval [CI], 1.09 to 1.53) more likely to use new needles/syringes during most recent injecting episode than participants who did not receive needles/syringes. The matched-samples estimate (i.e., average treatment effect on treated) of using new needles in the most recent injecting episode showed a 2.8% (95% CI, 0.0 to 5.6) increase in the use of new needles and a 6.5% (95% CI, −9.7 to −3.3) decrease in needle sharing in the most recent injecting episode in participants who received new needles/syringes. There was a 2.2% (95% CI, −3.8 to −0.6) decrease in needle sharing in the most recent injecting episode among participants who were referred to other services (integrated counselling and testing centre, detox centres, etc.).ConclusionsThe TI programme proved to be effective for behaviour change among IDUs, as substantiated by the use of new needles/syringes and sharing of needles/syringes.     

Hepatitis C virus antibody status, sociodemographic characteristics, and risk behaviour among injecting drug users in Croatia

The study was conducted among 76 injecting drug users (IDU) from seven Croatian cities during a three-year period (2005-2007). Each participant completed a questionnaire on sociodemographic characteristics and potential risk factors for hepatitis C virurs (HCV) infection followed by anti-HCV and anti-HIV antibody testing. The mean patient age was 30. The majority of patients (69.8%) reported more than one potential exposure to HCV: 97.1% had shared injecting equipment, 75% reported risk sexual behaviour, and 56.3% reported a history of travelling abroad. The overall HCV seroprevalence was 51.3% (95% CI = 40-63%). HCV seroprevalence increased with increasing number of risk behaviours (p = 0.026). Needle sharing frequency was the most important risk factor for hepatitis C. The HCV seroprevalence rate ranged from 27.3% in IDUs who answered that they shared needles occasionally to 100% in IDUs who always shared needles (p < 0.001). No other risk factors (age, gender, educational level, marital and employment status, history of travelling abroad and sexual risk behaviour) were associated with HCV seropositivity.     

Risk behaviours of young Indo-Chinese injecting drug users in Sydney and Melbourne

OBJECTIVE: To investigate patterns of drug use and injection-related risk behaviours among young Indo-Chinese injecting drug users (IDUs). METHOD: Cross-sectional survey. A structured questionnaire was administered to 184 Indo-Chinese IDUs aged 15 to 24 in Sydney and Melbourne. Participants were recruited using snowball sampling techniques; measures included patterns of heroin and other drug use, injection-related risk behaviours, perceived susceptibility to HIV and HCV infection and access to services. RESULTS: Despite perceived high availability of sterile injecting equipment, 36% had ever shared a needle and syringe and 22% had done so in the preceding month. Lifetime sharing was significantly associated with duration of injecting, history of incarceration and residence in Sydney. Sharing of injecting paraphernalia other than needles and syringes was also common, with young women and Sydney residents significantly more likely to report sharing equipment in the preceding month. CONCLUSIONS: Young Indo-Chinese IDUs are at high risk of infection with hepatitis C and other blood-borne viruses. Results indicate an urgent need for culturally appropriate and sustainable risk reduction programs which specifically target this population. Implications: Health services must respond swiftly to implement effective blood-borne virus prevention programs for young Indo-Chinese IDUs. Failure to do so may sustain the current epidemic of hepatitis C among IDUs.     

Irish injecting drug users and hepatitis C: the importance of the social context of injecting

BACKGROUND: The incidence of hepatitis C (HCV) infection among injecting drug users (IDUs) in Dublin is particularly high by international standards. The most robust predictor of an IDU's HCV status is his or her total number of lifetime injecting episodes. It has been proposed that participation in specific unsafe injecting practices is the principal contributor to this accumulated risk. We sought to test this hypothesis. The relationship between social context of injecting and HCV status was also examined. METHODS: We conducted a cross-sectional survey of IDUs recruited from treatment settings in Dublin. Participants had injected in the preceding six months and had not previously been tested for HCV. A structured interview was conducted. RESULTS: HCV testing was performed on 159 IDUs, and 61% were antibody positive. The three characteristics that were significant independent predictors of a positive test result were increased total number of lifetime injecting episodes, closer social relationships with other IDUs, and injecting in the home of other IDUs. Frequency of recipient syringe sharing (i.e. borrowing used syringes from other IDUs), backloading, and sharing of injecting paraphernalia were not independently associated with infection. CONCLUSIONS: We found that the robust association between HCV infection and number of lifetime injecting episodes was not explained by increased unsafe injecting practices. The socialized nature of heroin injecting in Dublin is contributing to the HCV epidemic in this population. Our findings suggest that accidental and unnoticed sharing of injecting equipment may be an important contributor to an IDU's increasing risk of infection over time.     

"The first shot": the context of first injection of illicit drugs, ongoing injecting practices, and hepatitis C infection in Rio de Janeiro, Brazil

The context of first drug injection and its association with ongoing injecting practices and HCV (hepatitis C virus) infection were investigated. Injection drug users (IDUs) (N = 606) were recruited in "drug scenes" (public places, bars) in Rio de Janeiro, Brazil, interviewed, and tested for HCV. Sharing of needles/syringes was more prevalent at the first injection (51.3%) than at the baseline interview (36.8%). Those who shared syringes/needles at first injection were more likely to be currently engaged in direct/indirect sharing practices. Among young injectors (< 30 years), those reporting sharing of needles/ syringes at the first injection were about four times more likely to have been infected by HCV. Hepatitis C virus prevalence among active IDUs (n = 272) was 11%. Prison history and longer duration of drug injection were identified as independent predictors of HCV infection. To effectively curb HCV transmission among IDUs and minimize harms associated with risk behaviors, preventive strategies should target individuals initiating drug injection beginning with their very first injection and discourage the transition from non-injecting use to the self-injection of illicit drugs.     

HCV status knowledge and risk behaviours amongst intravenous drug users

The aim of this study was to identify relationships between injecting and sexual risk behaviours and hepatitis C virus (HCV) status knowledge in intravenous drug users (IDUs). It was a cross-sectional survey (March 1994–June 1995) in 10 drug abuse treatment or psychosocial centres in Paris, France. We used a structured questionnaire about sexual, injecting, HIV and HCV antibody testing practices and results during the previous 6months. Six hundred and twelve sexually active IDUs aged 18 or older who were current injecting drug users were interviewed. Of 592 respondent IDUs, 37% did not report consistent HCV testing and 34% reported being HCV-positive. HCV-positive IDUs were older than HCV-negatives and HCV-unknowns. HCV-unknowns and HCV-positives had a lower educational level than HCV-negatives. After adjusting for demographic characteristics and HIV status, the factors associated with being HCV-unknown were not using condoms (OR: 2.9; 95% CI: 1.9–4.6) as well as clean equipment (OR: 1.8; 95% CI: 1.2–3.0). Not using new equipment was negatively associated with being HCV-unknown (OR: 0.4; 95% CI: 0.2–0.6) and with being HCV-positive (OR: 0.5; 95% CI: 0.3–0.8). Our study suggests that particular sexual and injecting risk-behaviours are associated with not knowing HCV status. As HCV-unknown IDUs are likely to be at the risk of transmitting HCV or acquiring other infections. HCV testing should be encouraged and associated with sexual counselling. Special attention should be paid to disinfecting practices for HCV-positives and use of new injecting equipment should be recommended for HCV-negatives.     

The concepts of risk and prevention from the perspective of injecting drug users

This paper provides an exploratory analysis, using a qualitative approach, to perceptions by injecting drug users (IDUs) on: (a) risks associated with injecting practices; (b) risks of HIV/AIDS; and (c) prevention of HIV/AIDS. The study was conducted in five harm reduction programs in Brazil (the AjUDE-Brasil Project). Forty semi-structured interviews were carried out. The study focuses on the concept of "risk". IDUs were mainly concerned over becoming ill and exposure to overdose and violence. IDUs dealt with individual problems in very specific ways in order to minimize them. They admitted that they were well informed about HIV/AIDS but lacked knowledge on reinfection and other bloodborne diseases. IDUs intended to follow guidelines established by health campaigns, but their addiction usually made it difficult. IDUs also suggested alternative harm reduction strategies and displayed a peculiar reading of concepts concerning sharing their injecting paraphernalia.     

High hepatitis C incidence in new injecting drug users: a policy failure?

OBJECTIVE: Evidence of ongoing hepatitis C (HCV) transmission among injecting drug users (IDUs) suggests a need for a better understanding of seroconversion characteristics among new IDUs and other vulnerable subgroups. This study aimed to determine incidence of HCV and associated risk factors among new IDUs in Sydney. METHODS: IDUs who had injected drugs in the past six months and who were unaware of their antibody HCV status or knew their serostatus to be negative were recruited through street-based outreach, methadone clinics and needle and syringe programs in south-western Sydney. Anti-HCV negative IDUs (n = 215) were enrolled and followed-up at 3-6 monthly intervals. New IDUs (n = 204) were defined as aged below 30 years or injecting for < or = 6 years at baseline. RESULTS: A total of 61 seroconversions were observed and incidence was 45.8 per 100 person years. Independent predictors of seroconversion were duration of injecting < 1 year (IRR = 3.10; 95% CI 1.47-6.54), female gender (IRR = 2.0; 95% CI 1.16-3.45), culturally and linguistically diverse background (CALDB) (IRR = 2.03; 95% CI 1.06-3.89) and intravenous cocaine use (IRR = 2.37; 95% CI 1.26-4.44). While new IDUs shared common risk factors, strong associations were observed between HCV seroconversion and sharing syringes, sharing other injecting equipment and backloading in CALDB new IDUs. CONCLUSION: Incidence of HCV infection among new IDUs in Sydney is unacceptably high. IMPLICATIONS: Extremely high rates of incident infection among newly initiated CALDB IDUs indicate an urgent need for enhanced policy and resource commitments to reduce the vulnerability of this group to HCV and other blood-borne infections.     

福建省近年来吸毒人群吸毒行为特征的调查分析

［目的］了解福建省吸毒人群的吸毒行为特征，为艾滋病防制措施的制定提供依据。［方法］1998-2000年，对福州市某强制戒毒所中的1637名戒毒人员进行问卷调查。［结果］吸毒者中注射吸毒的比例已从1998年的29.2%上升到2000年的61.0%，注射吸毒者中有21.1%曾与他人共用过注射针具。［结论］福建省注射吸毒者中存在HIV流行传播的危险性，迫切需要进行预防艾滋病的健康教育和行为干预活动。     

Prevalence of indirect sharing of drug-injecting paraphernalia in Galicia, Madrid, Seville and Valencia [Spain]

OBJECTIVES: To study drug-injecting practices, particularly indirect sharing of injecting paraphernalia (ISIP), and sexual risk behavior. METHODS: We performed a cross-sectional study of 1638 users of needle exchange programs (NEPs). Different types of ISIP were studied: taking diluted drugs in a syringe used by others, placing the needle in a recipient with other used needles, and reusing cleaning liquid previously used by others. RESULTS: The prevalence of injecting with syringes already used by others was 16% in Galicia, 4.7% in Madrid, 17.6% in Seville and 13.2% in Valencia (p < 0.001). With geographical variations, other types of ISIP (Galicia: 32.4%; Madrid: 28.5%; Seville: 42.6%; Valencia: 27.4% -p < 0.001-) were more frequent than injecting with syringes already used by others (Galicia: 32.4%; Madrid: 28.5%; Seville: 42.6%; Valencia: 27.4% -p < 0.001-). The percentage not injecting with syringes used by others but performing ISIP was 21.7%, 25.3%, 28.2% and 18.1% (p < 0.01) respectively. In all geographical areas, sexual risk practices were more prevalent with steady sex partners (68.6%, 72.0%, 77.8%, 72.8% [NS]) than with casual partners (36.6%, 40.9%, 37.9%, 23.9% [NS]). Among injectors with a stable partner, 81.3% in Galicia, 75.9% in Madrid, 86.1% in Seville and 79.7% in Valencia reported that his/her serological status was negative for HIV or was unknown (p < 0.001). CONCLUSIONS: ISIP is more prevalent than injection with syringes already used by others. For a substantial percentage of injectors, ISIP is the only risk practice. ISIP and the low use of condoms, particularly with steady partners, could be a contributory factor to the spread of HIV, hepatitis C virus, and hepatitis B virus infection.     

Border Crossing to Inject Drugs in Mexico Among Injection Drug Users in San Diego, California

We examined correlates of ever injecting drugs in Mexico among residents of San Diego, California. From 2007 to 2010, injecting drug users (IDUs) in San Diego underwent an interviewer-administered survey. Logistic regression identified correlates of injection drug use in Mexico. Of 302 IDUs, 38% were Hispanic, 72% male and median age was 37; 27% ever injected in Mexico; 43% reported distributive syringe sharing there. Factors independently associated with ever injecting drugs in Mexico included being younger at first injection, injecting heroin, distributive syringe sharing at least half of the time, and transporting drugs over the last 6 months. One-quarter of IDUs reported ever injecting drugs in Mexico, among whom syringe sharing was common, suggesting possible mixing between IDUs in the Mexico-US border region. Prospective studies should monitor trends in cross-border drug use in light of recent Mexican drug policy reforms partially decriminalizing drug possession.     

Recent incarceration independently associated with syringe sharing by injection drug users

OBJECTIVES: Few prospective studies are available on the relationship between incarceration and HIV risk among injection drug users (IDUs). The authors evaluated self-reported rates of syringe sharing and incarceration among a cohort of IDUs. METHODS: This study analyzed syringe lending by HIV-infected IDUs and syringe borrowing by HIV-negative IDUs among participants enrolled in the Vancouver Injection Drug Users Study (VIDUS). Since serial measures for each individual were available, variables potentially associated with each outcome (syringe lending and borrowing) were evaluated using generalized estimating equations for binary outcomes. RESULTS: The study sample consisted of 1,475 IDUs who were enrolled into the VIDUS cohort from May 1996 through May 2002. At baseline, 1,123 (76%) reported a history of incarceration since they first began injecting drugs. Of these individuals, 351 (31%) reported at baseline that they had injected drugs while incarcerated. Among 318 baseline HIV-infected IDUs, having been incarcerated in the six months prior to each interview remained independently associated with syringe lending during the same period (adjusted odds ratio [OR]=1.33; 95% confidence interval [CI] 1.06, 1.69; p=0.015). Similarly, among the 1,157 baseline HIV-negative IDUs, having been incarcerated in the six months prior to each interview remained independently associated with reporting syringe borrowing during the same period (adjusted OR=1.26; 95% CI 1.12, 1.44; p<0.001). CONCLUSIONS: Incarceration was independently associated with risky needle sharing for HIV-infected and HIV-negative IDUs. This evidence of HIV risk behavior should reinforce public health concerns about the high rates of incarceration among IDUs.