New Measures for Research on Men Who Have Sex with Men and for At-Risk Heterosexuals: Tools to Study Links Between Structural Interventions or Large-Scale Social Change and HIV Risk Behaviors, Service Use, and Infection.

Large-scale structural interventions and "Big Events" like revolutions, wars and major disasters can affect HIV transmission by changing the sizes of at-risk populations, making high-risk behaviors more or less likely, or changing contexts in which risk occurs. This paper describes new measures to investigate hypothesized pathways that could connect macro-social changes to subsequent HIV transmission. We developed a "menu" of novel scales and indexes on topics including norms about sex and drug injecting under different conditions, experiencing denial of dignity, agreement with cultural themes about what actions are needed for survival or resistance, solidarity and other issues. We interviewed 298 at-risk heterosexuals and 256 men who have sex with men in New York City about these measures and possible validators for them. Most measures showed evidence of criterion validity (absolute magnitude of Pearson's r ≥ 0.20) and reliability (Cronbach's alpha ≥ 0.70). These measures can be (cautiously) used to understand how macro-changes affect HIV and other risk. Many can also be used to understand risk contexts and dynamics in more normal situations. Additional efforts to improve and to replicate the validation of these measures should be conducted.

Experiences of Stigma and Support Reported by Participants in a Network Intervention to Reduce HIV Transmission in Athens, Greece; Odessa, Ukraine; and Chicago, Illinois.

A growing body of evidence suggests that network-based interventions to reduce HIV transmission and/or improve HIV-related health outcomes have an important place in public health efforts to move towards 90-90-90 goals. However, the social processes involved in network-based recruitment may pose a risk to participants of increasing HIV-related stigma if network recruitment causes HIV status to be assumed, inferred, or disclosed. On the other hand, the social processes involved in network-based recruitment to HIV testing may also encourage HIV-related social support. Yet despite the relevance of these processes to both network-based interventions and to other more common interventions (e.g., partner services), there is a dearth of literature that directly examines them among participants of such interventions. Furthermore, both HIV-related stigma and social support may influence participants' willingness and ability to recruit their network members to the study. This paper examines (1) the extent to which stigma and support were experienced by participants in the Transmission Reduction Intervention Project (TRIP), a risk network-tracing intervention aimed at locating recently HIV-infected and/or undiagnosed HIV-infected people and linking them to care in Athens, Greece; Odessa, Ukraine; and Chicago, Illinois; and (2) whether stigma and support predicted participant engagement in the intervention. Overall, experiences of stigma were infrequent and experiences of support frequent, with significant variation between study sites. Experiences and perceptions of HIV-related stigma did not change significantly between baseline and six-month follow-up for the full TRIP sample, and significantly decreased during the course of the study at the Chicago site. Experiences of HIV-related support significantly increased among recently-HIV-infected participants at all sites, and among all participants at the Odessa site. Both stigma and support were found to predict participants' recruitment of network members to the study at the Athens site, and to predict participants' interviewer-rated enthusiasm for naming and recruiting their network members at both the Athens and Odessa sites. These findings suggest that network-based interventions like TRIP which aim to reduce HIV transmission likely do not increase stigma-related risks to participants, and may even encourage increased social support among network members. However, the present study is limited by its associational design and by some variation in implementation by study site. Future research should directly assess contextual differences to improve understanding of the implications of site-level variation in stigma and support for the implementation of network-based interventions, given the finding that these constructs predict participants' recruitment of network members and engagement in the intervention, and thereby could limit network-based interventions' abilities to reach those most in need of HIV testing and care.

Young Drug Users: a Vulnerable Population and an Underutilized Resource in HIV/HCV Prevention.

PURPOSE OF REVIEW: The social networks of people who inject drugs (PWID) have long been studied to understand disease transmission dynamics and social influences on risky practices. We illustrate how PWID can be active agents promoting HIV, HCV, and overdose prevention. RECENT FINDINGS: We assessed drug users' connections and interactions with others at risk for HIV/HCV in three cities: New York City (NYC), USA (n = 539); Pereira, Colombia (n = 50); and St. Petersburg, Russia (n = 49). In all three cities, the majority of participants' network members were of a similar age as themselves, yet connections across age groups were also present. In NYC, knowing any opioid user(s) older than 29 was associated with testing HCV-positive. In NYC and St. Petersburg, a large proportion of PWID engaged in intravention activities to support safer injection and overdose prevention; in Pereira, PWID injected, had sex, and interacted with other key groups at risk. People who use drugs can be active players in HIV/HCV and overdose risk- reduction; their networks provide them with ample opportunities to disseminate harm reduction knowledge, strategies, and norms to others at risk. Local communities could augment prevention programming by empowering drug users to be allies in the fight against HIV and facilitating their pre-existing health-protective actions.

Using a "Positive Deviance" Framework to Discover Adaptive Risk Reduction Behaviors Among High-Risk HIV Negative Black Men Who Have Sex with Men.

Despite the high incidence of HIV among young Black MSM in the United States and engagement in high risk behaviors, many men in this group avoid infection. This suggests that some men may engage in systematic risk reduction behaviors when not always using condoms or abstaining from substances. Using a "positive deviance" framework, we conducted qualitative interviews with HIV-negative, Black MSM between 25 and 35 who reported unprotected anal sex and drug use in the past six months or current heavy drinking (N = 29) to discover behaviors that could facilitate remaining HIV-uninfected. Findings showed that MSM who remain HIV negative despite continuing to engage in high-risk behaviors may be engaging in adaptive risk reduction behaviors that, through successive decisions and advance planning along the timeline to a sexual event, could lead to increased condom use, avoidance or delay of a risky sexual event, or reduction of HIV positive partners.

Sexual Risk and Transmission Behaviors, Partnerships and Settings Among Young Adult Nonmedical Opioid Users in New York City.

Nonmedical prescription opioid use has become widespread. It can lead to heroin use, drug injection and HIV infection. We describe young adult opioid users' sexual risk behavior, partnerships and settings. 464 youth aged 18-29 who reported opioid use in the past 30 days were recruited using Respondent-Driven Sampling. Eligible participants completed a computer-assisted, interviewer-administered risk questionnaire and were tested for STIs and HIV. Participants (33% female; 66% white non-Hispanic) almost all had sex in the prior 90 days; 42% reported more than one partner. Same-sex sex was reported by 3% of men and 10% of women. Consistent condom use was rare. Seven percent reported group sex participation in the last 90 days but lifetime group sex was common among men and women. Young opioid users' unprotected sex, multiple partners and group sex puts them and others at high HIV and STI risk.

Understanding the effects of different HIV transmission models in individual-based microsimulation of HIV epidemic dynamics in people who inject drugs.

We investigated how different models of HIV transmission, and assumptions regarding the distribution of unprotected sex and syringe-sharing events ('risk acts'), affect quantitative understanding of HIV transmission process in people who inject drugs (PWID). The individual-based model simulated HIV transmission in a dynamic sexual and injecting network representing New York City. We constructed four HIV transmission models: model 1, constant probabilities; model 2, random number of sexual and parenteral acts; model 3, viral load individual assigned; and model 4, two groups of partnerships (low and high risk). Overall, models with less heterogeneity were more sensitive to changes in numbers risk acts, producing HIV incidence up to four times higher than that empirically observed. Although all models overestimated HIV incidence, micro-simulations with greater heterogeneity in the HIV transmission modelling process produced more robust results and better reproduced empirical epidemic dynamics.

STI/HIV Sexual Risk Behavior and Prevalent STI Among Incarcerated African American Men in Committed Partnerships: The Significance of Poverty, Mood Disorders, and Substance Use.

African Americans face disproportionate sexually transmitted infection including HIV (STI/HIV), with those passing through a correctional facility at heightened risk. There is a need to identify modifiable STI/HIV risk factors among incarcerated African Americans. Project DISRUPT is a cohort study of incarcerated African American men recruited from September 2011 through January 2014 from prisons in North Carolina who were in committed partnerships with women at prison entry (N = 207). During the baseline (in-prison) study visit, participants responded to a risk behavior survey and provided a urine specimen, which was tested for STIs. Substantial proportions reported multiple partnerships (42 %), concurrent partnerships (33 %), and buying sex (11 %) in the 6 months before incarceration, and 9 % tested positive for an STI at baseline (chlamydia: 5.3 %, gonorrhea: 0.5 %, trichomoniasis: 4.9 %). Poverty and depression appeared to be strongly associated with sexual risk behaviors. Substance use was linked to prevalent STI, with binge drinking the strongest independent risk factor (adjusted odds ratio: 3.79, 95 % CI 1.19-12.04). There is a continued need for improved prison-based STI testing, treatment, and prevention education as well as mental health and substance use diagnosis.

A new approach to prevent HIV transmission: Project Protect intervention for recently infected individuals.

Past research suggests that as many as 50% of onward human immunodeficiency virus (HIV) transmissions occur during acute and recent HIV infection. It is clearly important to develop interventions which focus on this highly infectious stage of HIV infection to prevent further transmission in the risk networks of acutely and recently infected individuals. Project Protect tries to find recently and acutely infected individuals and prevents HIV transmission in their risk networks. Participants are recruited by community health outreach workers at community-based HIV testing sites and drug users' community venues, by coupon referrals and through referrals from AIDS clinics. When a network with acute/recent infection is identified, network members are interviewed about their risky behaviors, network information is collected, and blood is drawn for HIV testing. Participants are also educated and given prevention materials (condoms, syringes, educational materials); HIV-infected participants are referred to AIDS clinics and are assisted with access to care. Community alerts about elevated risk of HIV transmission are distributed within the risk networks of recently infected. Overall, 342 people were recruited to the project and screened for acute/recent HIV infection. Only six index cases of recent infection (2.3% of all people screened) were found through primary screening at voluntary counseling and testing (VCT) sites, but six cases of recent infection were found through contact tracing of these recently infected participants (7% of network members who came to the interview). Combining screening at VCT sites and contact tracing the number of recently infected people we located as compared to VCT screening alone. No adverse events were encountered. These first results provide evidence for the theory behind the intervention, i.e., in the risk networks of recently infected people there are other people with recent HIV infection and they can be successfully located without increasing stigma for project participants.

Wetting transition in water.

Optical images were used to study the wetting behavior of water on graphite, sapphire, and quartz along the liquid vapor coexistence curve from room temperature to 300 °C. Wetting transitions were identified by the temperature at which the contact angle decreased to zero and also by the disappearance of dropwise condensation. These two methods yielded consistent values for the wetting temperatures, which were 185 °C, 234 °C, and 271 °C for water on quartz, sapphire, and graphite, respectively. We compare our results with the theoretical predictions based on a simplified model of the water-substrate potential and sharp interfaces.

Measuring the effects of an international health professions faculty development fellowship: the FAIMER Institute.

While there are many examples of evaluations of faculty development programs in resource rich countries, evaluation of transnational programs for faculty from developing countries is limited. We describe evaluation of the effects of the FAIMER Institute, an international health professions education fellowship that incorporates not only education content, but also leadership and management topics and, in addition, strives to develop a sustained community of educators. Data were obtained via retrospective pre/post surveys, as well as interviews. Results indicate that participating health professions faculty from developing countries are augmenting their knowledge and skills in education leadership, management, and methodology, and applying that knowledge at their home institutions. Fellows' perceptions of importance of, and their own competence in, all curriculum theme areas increased. Interviews confirmed a nearly universal gain of at least one leadership skill. Findings suggest that the high-engagement experience of the FAIMER model offering integration of education and leadership/management tools necessary to implement change, provides knowledge and skills which are useful across cultural and national contexts and results in the development of a supportive, global, professional network.

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.

Relative prevalence of different sexually transmitted infections in HIV-discordant sexual partnerships: data from a risk network study in a high-risk New York neighbourhood.

OBJECTIVES: To determine infection patterns of sexually transmitted infections that facilitate HIV transmission among HIV-discordant couples. METHODS: 112 initial respondents were recruited in an impoverished neighbourhood of Brooklyn, New York. Their sexual (and injection) partners were recruited in up to four additional network sampling waves for a final sample of 465 persons aged 18 years or older. After separate informed consent had been obtained, blood and urine were collected and tested for HIV, type-specific antibodies to herpes simplex virus (HSV-2), syphilis, chlamydia and gonorrhoea. RESULTS: Of 30 HIV-discordant partnerships, five were same-sex male partnerships and 25 were opposite-sex partnerships. No subjects tested positive for syphilis or gonorrhoea. Two couples were chlamydia-discordant. For HSV-2, 16 couples were double-positive, eight discordant, four double-negative, and two comprised a HSV-2-negative with a partner with missing herpes data. CONCLUSIONS: HSV-2 was present in 83% of the HIV-discordant couples, chlamydia in 7%, and syphilis and gonorrhoea in none. HSV-2 is probably more important for HIV transmission than bacterial sexually transmitted diseases because it is more widespread. Even given the limited generalisability of this community-based sample, there seems to be an important HIV-prevention role for herpes detection and prevention activities in places where HIV-infected people are likely to be encountered, including sexually transmitted disease clinics, HIV counselling and testing programmes, prisons, needle exchanges, and drug abuse treatment programmes. The effects of HSV-suppressive therapy in highly impacted groups should also be investigated.

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.

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

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.

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.

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.

Risk factors and HIV seropositivity among injecting drug users in Bangkok.

Bangkok experienced an extremely rapid spread of HIV infection among drug injectors in 1987 and 1988. This study examines risk factors for HIV infection and deliberate risk-reduction efforts by drug injectors. Two subsamples of injecting drug users were recruited in November 1989, a group in drug-use treatment (n = 342) and a group new to the treatment system (n = 259). Subjects were interviewed about AIDS risk behavior, and a blood sample was collected for HIV testing. Seroprevalence was 39 and 27% in the in-treatment sample and the new-to-treatment sample, respectively. The in-treatment sample seroprevalence rate is similar to rates observed 6 and 12 months earlier. Three factors were independently associated with HIV infection: subsample, having been in prison, and sharing injection equipment with two or more individuals in the previous 6 months. Deliberate risk reduction was reported by 92% of individuals, with 59% reporting that they had stopped sharing injection equipment. It appears that large-scale risk reduction has greatly slowed HIV transmission among drug injectors in Bangkok.

Development of AIDS, HIV seroconversion, and potential co-factors for T4 cell loss in a cohort of intravenous drug users.

A cohort of 334 intravenous (IV) drug users from New York City drug treatment programs were followed over a mean 9-month period. Among the 165 who were seropositive at enlistment, four developed clinical AIDS, for an annual rate of 3%. Elevated IgA was a significant predictor of developing AIDS. Among 72 subjects who were initially seronegative and who were re-interviewed, four were seropositive at follow-up, for a seroconversion rate of 7% per year among seronegatives. Among seropositive subjects who did not develop AIDS or fatal AIDS related complex (ARC), continued drug injection was associated with rate of T4 cell loss, and there was a non-significant trend for males to lose T4 cells more rapidly than females. While it was not possible to distinguish the mechanism underlying the relationship between continued drug injection and T4 cell loss, seropositive IV drug users should be warned that continued injection may lead to increased HIV-related immunosuppression as well as, if injection equipment is shared, risking viral transmission to others.