Geographic distribution of risk ("Hotspots") for HIV, HCV, and drug overdose among persons who use drugs in New York City: the importance of local history.

AIMS: To identify geographic "hotspots" for potential transmission of HIV and HCV and for drug overdose among persons who use heroin and cocaine in New York City and to examine historical continuities in problem drug use hotspots in the city. METHODS: A total of 2714 study participants were recruited among persons entering Beth Israel substance use treatment programs. A structured questionnaire was administered and blood samples for HIV and HCV testing were collected. Hotspots for potential virus transmission were defined as ZIP codes with 10+ participants, 2+ persons infected with the virus and engaging in transmission behavior, and 2+ persons not infected and engaging in acquisition behavior. ZIP codes with 3+ persons with previous overdoses were considered potential hotspots for future overdoses. RESULTS: Participants resided in 166/178 (93%) of the ZIP codes in New York City. Injecting drug use was reported in 150/178 (84%) of the ZIP codes. No zip codes were identified for injecting-related HIV transmission, 5 zip codes were identified for sexual HIV transmission, 3 for HCV transmission, and 8 for drug overdose. Many of the ZIP code potential hotspots were in neighborhoods long associated with drug use: Lower Eastside and Harlem in Manhattan, the South Bronx, and Central Brooklyn. DISCUSSION: Heroin and cocaine use requiring treatment were reported from almost all ZIP codes in New York City, indicating needs for widely dispersed harm reduction services. Identified hotspots should be targeted for reducing sexual transmission of HIV, transmission of HCV, and drug overdoses. Some of the hotspots have persisted as problem drug use areas for 40 to over 100 years. Monitoring of drug use patterns in historical hotspot neighborhoods may permit early identification of and response to emerging drug use-related health problems. Persistent historical hotspots for problem drug use present a complex problem for implementing harm reduction services that deserve additional research.

Combined HIV prevention, the New York City condom distribution program, and the evolution of safer sex behavior among persons who inject drugs in New York City.

Examine long term sexual risk behaviors among persons who inject drugs (PWID) in New York City following implementation of "combined" prevention programming, including condom social marketing. Quantitative interviews and human immunodeficiency virus (HIV) testing were conducted among PWID entering Beth Israel Medical Center drug treatment programs 1990-2012. Data were analyzed by four time periods corresponding to the cumulative implementation of HIV prevention interventions. 7,132 subjects were recruited from 1990 to 2012; little change in sexual behavior occurred among HIV seronegative subjects, while HIV seropositive subjects reported significant decreases in being sexually active and significant increases in consistent condom use. HIV transmission risk (being HIV positive and engaging in unprotected sex) declined from 14 % in 1990-1995 to 2 % in 2007-2012 for primary sexual partners and from 6 to 1 % for casual partners. Cumulative implementation of combined prevention programming for PWID was associated with substantial decreases in sexual risk behavior among HIV seropositives.

Risk for Heterosexual HIV Transmission Among Non-Injecting Female Partners of Injection Drug Users in Estonia.

The HIV epidemic in Estonia, as with other eastern European countries, is currently concentrated among injection drug users (IDUs). Non-IDUs who have IDU sex partners could serve as a potential bridge in an expanding epidemic. We applied HIV transmission modelling to data collected from non-IDU/IDU heterosexual couples in Kohtla-Järve, Estonia to estimate HIV risk from IDUs to their sex partners based on self-reported sexual behaviors shared by the couple. IDUs and their current main non-injecting sex partners were recruited for an interviewer-administered survey and HIV testing. Bernoulli modelling techniques were applied to estimate the risk of HIV transmission (incidence) among HIV negative non-injecting female partners of male IDUs. The estimated HIV incidence in this population of non-injecting women with only main sexual partners in the last 6 months ranged from 3.24 to 4.94 HIV seroconversions per 100 person years depending on the value used in the models for the per act transmission rate during acute stage infection. Non-IDUs who have IDU sex partners are at high risk for HIV and could serve as a potential bridge to a more generalized epidemic. Whether this might lead to an expansion of the HIV epidemic beyond core groups in Estonia or other Eastern European countries warrants closer study.

Hepatitis C virus-specific immune responses in noninjecting drug users.

Noninjection drug use, although recognized as an emerging risk factor for acquisition of other blood-born pathogens, is still unconfirmed as a route of hepatitis C virus (HCV) transmission. Our goal was to measure HCV exposure and prevalence in noninjection drug users (NIDUs). Fifty-seven NIDUs were screened by extensive questionnaire to exclude prior injection drug use and evaluated for HCV-specific serologic and cellular immune responses. HCV-specific T-cell responses were measured using interferon-gamma (IFN-γ) enzyme-linked immunospot (ELISpot) assay with overlapping HCV peptides covering the entire HCV genome. Fifteen individuals who never used illicit drugs served as negative controls. Eleven people with no history of injecting drug use (19.3%) were HCV seropositive: seven with chronic HCV infection and four with previously resolved infection. Of 51 NIDUs with ELISpot results, HCV-specific cellular immunity was detected in 5 (9.8%). These responses were relatively weak and narrow. We did not find significant associations between HCV-specific immune responses and noninjection drug use practices. Subjects with HCV-specific immunity, however, were significantly more likely to have bought sex in the past 6 months, to have had more casual partners of the opposite sex in the last 6 months, and those partners were more likely to have ever injected drugs compared to subjects without HCV-specific immunity. In summary, we found serologic or cellular HCV-specific immune responses in 27.5% of NIDUs. Our results suggest that sexual behaviour associated with noninjection drug use might be a risk factor for HCV acquisition. Additional studies are needed to precisely determine the practices that lead to HCV exposure among this population.

Emergent properties of HIV risk among injection drug users in Tallinn, Estonia: synthesis of individual and neighbourhood-level factors.

OBJECTIVES: HIV/AIDS risk is embodied within multiple levels including structural and social levels. The aim of this study was to assess the effects of neighbourhood characteristics on HIV prevalence among injection drug users (IDU) residing in the area of Tallinn, Estonia in 2007. METHODS: A cross-sectional, multilevel design collecting individual-level data--a behaviour survey including data on self-reported residency and HIV antibody testing among 350 IDU and neighbourhood-level data--aggregate measures on socio-demo-economic residential characteristics from the 2000 Estonian census. Geocoding and multilevel modelling analysis was employed. RESULTS: Among the 350 IDU recruited, earlier age at first injection, fentanyl as the main injection drug, receptive syringe sharing, main income source other than legal employment and ever attended a syringe exchange programme remained significantly associated with increased odds of anti-HIV positivity in the multivariable analysis involving individual effects with no predictors at the neighbourhood level. In the multilevel model, individual (earlier at IDU initiation AOR 1.86, 95% CI 1.01 to 3.44; injecting opioids AOR 4.43, 95% CI 2.74 to 7.18; receptive syringe sharing AOR 2.51, 95% CI 1.86 to 3.37; main income source other than work AOR 2.04, 95% CI 1.32 to 3.14; ever attended a syringe exchange programme AOR 2.58, 95% CI 1.83 to 3.61) and neighbourhood level (higher unemployment rate AOR 5.95, 95% CI 2.47 to 14.31; greater residential change AOR 1.89, 95% CI 1.09 to 3.26) emerged as significant predictors of individual HIV-positive status. CONCLUSIONS: Our results indicate that both individual-level and emergent neighbourhood-level factors contribute to HIV risk among IDU and are amenable for preventive interventions.

Hepatitis C virus-specific T-cell immune responses in seronegative injection drug users.

T-cell responses to hepatitis C virus (HCV) antigens have been reported in high-risk HCV seronegative persons, suggesting that an effective cellular immune response might be able to clear infection without the development of antibodies. Such findings, however, could be explained by waning antibody or cross-reactivity to other antigens. To address these issues, we evaluated HCV-specific T-cell responses in 26 young (age 18-33 years) aviremic, seronegative injection drug users (IDUs) (median duration of injection, 6 years) by interferon-gamma enzyme-linked immunospot (ELISpot) assay using 429 overlapping HCV peptides pooled in 21 mixes. Seventeen aviremic, seropositive IDUs (spontaneous resolvers) and 15 healthy people were used as positive and negative controls, respectively. The percentage of patients with HCV-specific cellular immune responses was similar in seronegative and seropositive aviremic IDUs (46%vs 59%, P = 0.4), while these responses were not detected in any of the negative controls. Among the seronegative IDUs, six (23%) had intermediate to very strong responses to 10-20 peptide mixes and another six (23%) had moderately strong responses for two to six mixes. The 12 seronegative IDUs with HCV-specific T-cell responses had higher demographical and behavioural risk profiles than the 14 IDUs without T-cell responses (estimated risk of HCV infection, 0.47 vs 0.26, P < 0.01). In conclusion, HCV-specific T-cell responses are common among high-risk, seronegative IDUs. The responses are broad and are associated with risk factors for HCV exposure, suggesting that they reflect true exposure to HCV in seronegative persons.

A larger spectrum of severe HIV-1--related disease in intravenous drug users in New York City.

Increasing mortality in intravenous (IV) drug users not reported to surveillance as acquired immunodeficiency syndrome (AIDS) has occurred in New York City coincident with the AIDS epidemic. From 1981 to 1986, narcotics-related deaths increased on average 32% per year from 492 in 1981 to 1996 in 1986. This increase included deaths from AIDS increasing from 0 to 905 and deaths from other causes, many of which were infectious diseases, increasing from 492 to 1091. Investigations of these deaths suggest a causal association with human immunodeficiency virus (HIV) infection. These deaths may represent a spectrum of HIV-related disease that has not been identified through AIDS surveillance and has resulted in a large underestimation of the impact of AIDS on IV drug users and blacks and Hispanics.

Being "hooked up" during a sharp increase in the availability of illicitly manufactured fentanyl: Adaptations of drug using practices among people who use drugs (PWUD) in New York City.

Illicitly manufactured fentanyl (IMF), a category of synthetic opioids 50-100 times more potent than morphine, is increasingly being added to heroin and other drugs in the United States (US). Persons who use drugs (PWUD) are frequently unaware of the presence of fentanyl in drugs. Use of heroin and other drugs containing fentanyl has been linked to sharp increases in opioid mortality. In New York City (NYC), opioid-related mortality increased from 8.2 per 100,000 residents in 2010 to 19.9 per 100,000 residents in 2016; and, in 2016, fentanyl accounted for 44% of NYC overdose deaths. Little is known about how PWUD are adapting to the increase in fentanyl and overdose mortality. This study explores PWUDs' adaptations to drug using practices due to fentanyl. In-depth qualitative interviews were conducted with 55 PWUD at three NYC syringe services programs (SSP) about perceptions of fentanyl, overdose experiences and adaptations of drug using practices. PWUD utilized test shots, a consistent drug dealer, fentanyl test strips, naloxone, getting high with or near others and reducing drug use to protect from overdose. Consistent application of these methods was often negated by structural level factors such as stigma, poverty and homelessness. To address these, multi-level overdose prevention approaches should be implemented in order to reduce the continuing increase in opioid mortality.

Potential geographic "hotspots" for drug-injection related transmission of HIV and HCV and for initiation into injecting drug use in New York City, 2011-2015, with implications for the current opioid epidemic in the US.

OBJECTIVE: We identified potential geographic "hotspots" for drug-injecting transmission of HIV and hepatitis C virus (HCV) among persons who inject drugs (PWID) in New York City. The HIV epidemic among PWID is currently in an "end of the epidemic" stage, while HCV is in a continuing, high prevalence (> 50%) stage. METHODS: We recruited 910 PWID entering Mount Sinai Beth Israel substance use treatment programs from 2011-2015. Structured interviews and HIV/ HCV testing were conducted. Residential ZIP codes were used as geographic units of analysis. Potential "hotspots" for HIV and HCV transmission were defined as 1) having relatively large numbers of PWID 2) having 2 or more HIV (or HCV) seropositive PWID reporting transmission risk-passing on used syringes to others, and 3) having 2 or more HIV (or HCV) seronegative PWID reporting acquisition risk-injecting with previously used needles/syringes. Hotspots for injecting drug use initiation were defined as ZIP codes with 5 or more persons who began injecting within the previous 6 years. RESULTS: Among PWID, 96% injected heroin, 81% male, 34% White, 15% African-American, 47% Latinx, mean age 40 (SD = 10), 7% HIV seropositive, 62% HCV seropositive. Participants resided in 234 ZIP codes. No ZIP codes were identified as potential hotspots due to small numbers of HIV seropositive PWID reporting transmission risk. Four ZIP codes were identified as potential hotspots for HCV transmission. 12 ZIP codes identified as hotspots for injecting drug use initiation. DISCUSSION: For HIV, the lack of potential hotspots is further validation of widespread effectiveness of efforts to reduce injecting-related HIV transmission. Injecting-related HIV transmission is likely to be a rare, random event. HCV prevention efforts should include focus on potential hotspots for transmission and on hotspots for initiation into injecting drug use. We consider application of methods for the current opioid epidemic in the US.

Needle exchange use, sexual risk behaviour, and the prevalence of HIV, hepatitis B virus, and hepatitis C virus infections among Bulgarian injection drug users.

At a time when the rates of HIV, hepatitis C virus (HCV), and hepatitis B virus (HBV) infections have risen among injection drug users (IDUs) in other countries in the region, little is known about the prevalence of these infections among Bulgarian injectors and about their sexual risk behaviours. IDUs (n = 773) in a community-based needle exchange programme (NEP) and two major drug treatment facilities in Sofia completed a structured interview and were tested for HIV, HBV, and HCV antibodies. While HCV prevalence in the sample was 73.9%, HBV and HIV prevalence was low -6% and 0.5%, respectively. Having more than 10 sexual partners, having sex with someone with hepatitis C or another IDU, and never using a condom with another IDU were common among those who were recruited through NEP. As 40% of the IDUs reported using NEP, it appears that needle exchange provides an opportunity to reach high-risk populations and prevent sexual transmission of blood-borne pathogens.

HIV research productivity and structural factors associated with HIV research output in European Union countries: a bibliometric analysis.

OBJECTIVES: To assess HIV/AIDS research productivity in the 27 countries of the European Union (EU), and the structural level factors associated with levels of HIV/AIDS research productivity. METHODS: A bibliometric analysis was conducted with systematic search methods used to locate HIV/AIDS research publications (period of 1 January 2002 to 31 December 2011; search databases: MEDLINE (Ovid, PubMed), EMBASE, ISI-Thomson Web of Science; no language restrictions). The publication rate (number of HIV/AIDS research publications per million population in 10 years) and the rate of articles published in HIV/AIDS journals and selected journals with moderate to very high (IF ≥3) 5-year impact factors were used as markers for HIV research productivity. A negative binomial regression model was fitted to assess the impact of structural level factors (sociodemographic, health, HIV prevalence and research/development indicators) associated with the variation in HIV research productivity. RESULTS: The total numbers of HIV/AIDS research publications in 2002-2011 by country ranged from 7 to 9128 (median 319). The median publication rate (per million population in 10 years) was 45 (range 5-150) for all publications. Across all countries, 16% of the HIV/AIDS research was published in HIV/AIDS journals and 7% in selected journals with IF ≥3. Indicators describing economic (gross domestic product), demographic (size of the population) and epidemiological (HIV prevalence) conditions as well as overall scientific activity (total research output) in a country were positively associated with HIV research productivity. CONCLUSIONS: HIV research productivity varies noticeably across EU countries, and this variation is associated with recognisable structural factors.

Structural interventions to reduce HIV transmission among injecting drug users.

OBJECTIVE: To review current knowledge of 'structural' interventions to reduce HIV transmission among injecting drug users. Structural interventions are defined as programs or policies that change the environments in which risk behavior occurs, without attempting to change knowledge, attitudes or social interaction patterns of the persons at risk. Structural interventions may either facilitate enactment of existing motives to avoid HIV transmission or make enacting risk behavior more difficult. METHODS: Nonquantitative literature review. RESULTS AND CONCLUSIONS: Preventing HIV infection among injecting drug users must be considered within the context of the continuing global spread of psychoactive drug use, and injecting drug use in particular. Some policies that are designed to reduce drug use may tend to increase HIV transmission among persons who do inject drugs. Evaluation of structural interventions can be difficult, as populations of drug users are usually the relevant unit of analysis. Typically, pre versus post comparisons must be used, hopefully with multiple pre and post data points. Structural interventions are often associated with 'large effects', increasing confidence that the intervention is the cause of the reduction in HIV-risk behavior. Increasing the availability of sterile injection equipment, through pharmacy sales or syringe exchange or both, is the most common and best-studied structural intervention for injecting drug users. The studies to date indicate that this usually, but not always, leads to large reductions in HIV-risk behavior. Involving drug users in the design and implementation of HIV-prevention programs can be considered a 'meta-structural' intervention that should lead to programs with increased effectiveness.

HIV and intravenous drug use.

There is now evidence from a wide variety of geographic areas that many intravenous drug users will change their behavior in order to reduce their risk of developing AIDS. There is even evidence from some areas that the behavior change has led to relative stabilization of seroprevalence rates, although longer-term studies will be needed to establish this definitively. AIDS behavior change in the area of sexual risk reduction appears to be much more difficult than change of drug injection behavior. Conceptual models of AIDS-related behavior change are needed, particularly models that can incorporate the injection of different drugs and variation in social and psychological characteristics among drug injectors. There is increasing evidence for a wider spectrum of HIV-related morbidity and mortality among intravenous drug users than is captured by the current surveillance definition for AIDS, again emphasizing the need for effective prevention programs.

PIP: Topics concerning intravenous drug use and AIDS are reviewed. Topics include seroprevalence of HIV among users worldwide, evidence that iv drug users will alter behavior to avoid AIDS, results of safer injections programs, no evidence for reduction in high-risk behavior regarding sexual transmission of AIDS by users, diversity in HIV prevalence among users, and clinical aspects of their disease. Seroprevalence of HIV among drug users has remained at about 30% in the U.S. and parts of Europe, while lower in Asia and South America. There is now evidence from several places in Europe and the U.S. that many iv drug users will change drug injecting behavior to avoid AIDS. A conceptual model of new social norms needed to change behavior involves 3 stages: knowing the dangers of AIDS, having the means to change behavior (treatment or clean syringes), and a mechanism to reinforce the new behavior (perceived efficacy or social approval). There is no evidence that safer injection programs either keep users from going to treatment or increase numbers of users. In contrast, there is no evidence for improved sexual risk-taking behaviors among users, a fact which argues for stronger efforts to prevent already infected users from spreading HIV. The public, policy-markers, and researchers are unaware that seroprevalence of HIV varies with the type of drug injected (cocaine; heroin; amphetamine), and with socioeconomic status of the user (ethnic minority; majority). The clinical presentation, infection rate, persistence of infection, and mortality rate among iv drug users differs from that of the general AIDS population. Endocarditis, tuberculosis and bacterial pneumonias are 3 of the common findings in drug users. Even "non-AIDS" deaths apparently due to immunosuppression are reported in drug users. There may be undiscovered co-factors in HIV infection in this population.

HIV infection among intravenous drug users: epidemiology and risk reduction.

Research on the epidemiology of HIV infection among IV drug users is still at a relatively early stage. Multilocation studies that would permit better geographic comparisons are greatly needed. Multi-method studies within single geographic areas are also needed to assess possible biases with respect to sample recruitment and data collection procedures. The continuation of the epidemic provides a changing historical context that complicates any comparisons. Despite these problems, there are some consistencies that can be seen across studies. Studies of HIV seroprevalence among IV drug users show wide variation among cities in the United States and Europe. The time that the virus was introduced into the IV drug using group within the city is one factor in explaining these differences; other cross-city factors have yet to be identified. Once HIV has been introduced into the IV drug use group within a particular geographic area, there is the possibility of rapid spread up to seroprevalence levels of 50% or greater. Thus, a currently low seroprevalence rate should not be seen as a stable situation. Frequency of injection and sharing of equipment with multiple other drug users (particularly at shooting galleries) have been frequently associated with HIV exposure. Being female, ethnicity (in the USA) and engaging in prostitution also may be associated with increased risk for HIV exposure, suggesting that prevention programs should include special consideration of sex and ethnic differences. Studies of AIDS risk reduction show that substantial proportions of IV drug users are changing their behavior to avoid exposure to HIV. This risk reduction is probably more advanced in New York, with its high seroprevalence and incidence of cases, but is also occurring in cities with lower seroprevalence and limited numbers of cases. The primary forms of risk reduction are increasing the use of sterile equipment, reducing the number of needle sharing partners, and reducing the frequency of injection. These behavior changes are very similar to the frequently identified behavioral risk factors associated with HIV exposure, suggesting that they should be effective in at least slowing the spread of HIV among IV drug users. No linkage of risk reduction to decreases in seroconversion has yet been shown, however, and greater risk reduction is clearly required. A variety of prevention strategies will probably be needed to reduce the spread of HIV among IV drug users. Prevention of initiation into drug injection is an undeniable long-term goal for the control of HIV infection, but there is very little research being conducted in this area.

PIP: Published and unpublished reports on HIV seroprevalence and risk reduction among IV drug users (IVDU) are reviewed as of 1986. The seroprevalence of HIV among IVDUs varies widely by location, often with a north-south gradient. The strongest indicator of prevalence is the date of introduction of HIV, with rates as high as 50% appearing within 2 years. The behavioral risk factors are sharing injection equipment partners, using shooting galleries, being a female prostitute or a member of a minority ethnic group. There are no data yet on whether removing barriers to sterile syringes and needles or needle exchange programs is effective in cutting the spread of HIV. There are some hints that IVDUs are capable of altering risky behavior. Surveys of 2 groups of methadone maintenance client suggest increased knowledge of HIV risks and increased use of clean needles. It is reported that the black market for needles in New York City has shown increased sales, that sales of syringes with extra needles are popular, that heroin sellers are including sterile syringes with bags, and even that re-packaged used unsterile needles are enjoying a brisk profit on the street. There are suggestions that IVDUs in Amsterdam and San Francisco are altering their high risk behaviors. Data from Amsterdam shows that IVDUs have not increased their frequency of injection nor reduced their demand for drug treatment as a result of the needle exchange program. Possible prevention strategies are education of people before they initiate IV drug use; provision of ample drug treatment as a cost effective means of reducing the expense of treating AIDS patients; and providing sterile needles or teaching IVDUs how to clean syringes and needles. Probably a mixed strategy will be to reduce the risk of HIV or IVDUs.

HIV surveillance among injecting drug users.

Injecting drug users (IDUs) should be considered a 'partially hidden population' at high risk for HIV infection. In almost all locations it should be possible to locate and conduct research with IDUs, but it will probably never be possible to enumerate or draw random samples from an IDU population. Surveillance research studies with IDUs should include risk behaviors, as surveillance of HIV infection only will not be sufficiently time sensitive, and be used to develop and refine HIV prevention programming for the population. Contacts with IDUs can be developed at multiple settings, including voluntary treatment programs, law enforcement settings, and through 'street outreach.' Each type of setting has different advantages, disadvantages and ethical concerns. HIV testing as part of surveillance also raises additional important ethical concerns. The primary risk behaviors that should be included in surveillance studies are 'sharing' of drug injection equipment, the potential for rapid partner change among risk partners, and sexual risk behavior. Additional important objectives for surveillance research include: (1) the size of the local IDU population, (2) patterns of drug use, (3) availability injection equipment, (4) participation in prevention activities, and (5) access to and use of anti-retroviral treatments. HIV incidence is an ultimate objective for surveillance research, but there are no currently available cost-efficient methods for studying HIV incidence, so estimation from indirect measurements is usually required.

Street-recruited intravenous drug users and sexual risk reduction in New York City.

Previous studies have reported that intravenous drug users (IVDUs) have made considerable drug-use risk reduction, but less sexual risk reduction. This paper presents findings about sexual risk reduction by street-recruited IVDUs in New York City, and examines the predictors of sexual risk reduction. Sixty-one per cent of these street-recruited IVDUs have initiated deliberate sexual risk reduction in order to avoid AIDS. For the total sample (n = 568), as well as for the male IVDUs, specific health belief and social influence factors were significant predictors of sexual risk reduction. For female IVDUs, drug-risk reduction, having a friend or acquaintance who practices sexual risk reduction, and wanting to have a(nother) child were significant predictors of sexual risk reduction. These findings suggest the importance of social support and community organization to promote risk reduction.

International epidemiology of HIV and AIDS among injecting drug users.

PIP: HIV/AIDS and iv drug use (IVDU) are of significant multinational scope and growing. Supporting increased IVDU in many countries are countries' geographical proximity to illicit drug trafficking distribution routes, law enforcement efforts which increase the demand for more efficient drug distribution and consumption, and countries' infrastructural and social modernization. Given the failures of intensified law enforcement efforts to thwart the use and proliferation of illegal drugs, countries with substantial IVDU should look away from preventing use to preventing HIV transmission within drug user populations. With HIV seroprevalence rates rapidly reaching 40-50% in some developing country IVDU groups, a variety of prevention programs is warranted. Such programs should be supported and implemented while prevention remains feasible. This paper examines the variation in HIV seroprevalence among IVD users, rapid HIV spread among users, HIV among IVDUs in Bangkok, emerging issues in HIV transmission among IVDUs, non-AIDS manifestations of HIV infection among IVDUs, prevention programs and effectiveness, and harm reduction.^ieng

Syringe-mediated drug-sharing (backloading): a new risk factor for HIV among injecting drug users.

BACKGROUND: In syringe-mediated drug-sharing (backloading), injecting drug users (IDU) use their syringes to mix drugs and to give measured shares to other IDU by squirting drug solution into the syringes of other IDU. Backloading has been discussed as a potential HIV risk factor, but its role as an HIV transmission route has not been established empirically. METHODS: Six hundred and sixty IDU who had injected drugs in the previous 2 years were street-recruited from Bushwick, New York City through chain referral, tested for HIV antibody and interviewed about sexual and drug-risk behaviors. RESULTS: Receiving drugs via backloading in the previous 2 years was reported by 24.5% of the subjects. These subjects had significantly higher HIV seroprevalence than those who did not receive drugs by backloading (odds ratio, 2.2; 95% confidence interval, 1.5-3.1). Backloading remained positively and significantly associated with HIV seropositivity in stepwise logistic regression, and in a series of simultaneous logistic models controlling for sociodemographic variables and for sexual and drug risk variables. CONCLUSIONS: Backloading can be a route of HIV transmission among IDU and should be incorporated into risk-factor studies and HIV transmission modeling. Many IDU who avoid other high-risk drug-injection practices may overlook the risk of backloading. HIV prevention programs should warn IDU against syringe-mediated drug-sharing and work together to develop ways to avoid it.

Condom use with primary partners among injecting drug users in Bangkok, Thailand and New York City, United States.

OBJECTIVE: To determine factors associated with likelihood or failure to use condoms with primary sexual partners among injecting drug users (IDU) in two cities. DESIGN AND METHODS: Interviews were conducted with 601 IDU in Bangkok in 1989 and with 957 IDU in New York City in 1990-1991. Subjects were recruited from drug-use treatment programs and a research storefront. Informed consent was obtained and a World Health Organization standardized questionnaire about AIDS risk behaviors administered by a trained interviewer. RESULTS: A substantial minority (37%) of IDU in Bangkok and a majority (55%) of IDU in New York City reported penetrative intercourse (vaginal, anal or oral) with a primary partner in the 6 months before the interview. Of those reporting penetrative intercourse with a primary partner, only 12% in Bangkok and 20% in New York reported that they always used condoms. Parallel bivariate and multiple logistic regression analyses were conducted to distinguish between subjects who reported always using condoms and subjects who reported unsafe sexual activity with primary partners. The same two factor--knowing that one is HIV-seropositive and talking about AIDS with sexual partners--were most strongly associated with always using condoms with primary partners in both cities. CONCLUSIONS: Programs to prevent sexual transmission of HIV among IDU should provide voluntary and confidential/anonymous HIV counseling and testing, and should facilitate discussions of AIDS and sexual transmission of HIV between IDU and their sexual partners. That the same two factors were associated with always using condoms with primary partners among IDU in these two cities suggests that these factors may also be important in other groups at high risk for HIV.

PIP: Trained interviewers spoke to 957 drug users attending a detoxification program, methadone maintenance program, or a research storefront in New York City in 1990-91 and to 601 drug users attending 17 drug use treatment clinics in Bangkok, Thailand, in the autumn of 1989 as part of a study to identify factors linked to the probability or failure of condom use with primary sexual partners among IV drug users. The participants also received HIV counseling and testing. IV drug users in New York City were more likely to be older (36.2 years vs. 30.1 years; p .001), female (25% vs. 5%; p .001), more ethnically diverse (p .001), and inject cocaine more often (33 injections/month vs. 0.5 injections/month) than those in Bangkok. 44% of drug users in New York City and 33% of those in Bangkok engaged in some unprotected penetrative intercourse with a primary heterosexual partner in the previous 6 months. Of drug users having penetrative sexual intercourse with a primary partner in the previous 6 months, 20% in New York City and 12% in Bangkok always used condoms (p .02). The strongest predictors of condom use among IV drug users from both countries were a previous positive HIV test and talking about AIDS with sexual partners (p = .001 for US; p = .0008 for Bangkok and p = .004 for US; p = .0596 for Bangkok, respectively). These findings indicated that unsafe sexual behavior with primary sexual partners among drug users is still a major source of HIV transmission in these 2 cities. Nevertheless, knowledge of HIV positive status and partner communication concerning AIDS are predictors of condom use shared by both groups. Thus, HIV/AIDS prevention programs should provide confidential HIV testing and counseling for drug users and should encourage frank discussions of AIDS between drug users and primary sexual partners. Peer support for risk reduction among drug users has the potential to facilitate such discussions.

Consistent condom use in relationships between seropositive injecting drug users and sex partners who do not inject drugs.

OBJECTIVES: To study how condom use in injecting drug users' (IDU) relationships differs according to whether they are HIV-infected, and to whether their sex partner is an IDU. DESIGN AND METHODS: A total of 317 street-recruited IDU were HIV-antibody tested and interviewed about 421 relationships with particular sex partners. RESULTS: Condoms were consistently (100%) used in sex between partners (during the previous 30 days) in 33% of these relationships, and their use was significantly more frequent in relationships of seropositive IDU and in relationships with non-IDU partners. In relationships between seropositive IDU and non-IDU, consistent condom use was reported to be high (68%); this remained unchanged under multivariate controls. CONCLUSIONS: Self-reported condom use by IDU in New York, with its relatively mature epidemic, appears to be concentrated where it may most reduce the spread of HIV to non-IDU heterosexuals, i.e., in relationships between infected IDU and non-IDU partners. Differential condom use by serostatus and by partners' drug injection should be incorporated into mathematical models of the HIV epidemic. Causes of the high level of condom use in this subset of relationships may include drug injector altruism and pressure by sex partners; prevention programs should develop ways to use both of these factors to motivate increased condom use.