Drug treatment as HIV prevention: expanding treatment options

Research conducted during the first 20 years of the AIDS epidemic provided a solid foundation of data supporting methadone treatment as HIV prevention. Drug users in methadone treatment were consistently found to reduce the frequency of drug use, risk behaviors, and infections. These data have been consistent over time and across cultural settings and have been used to promote the expansion of drug treatment as a prevention intervention. More recently, data have emerged suggesting the prevention potential of medication-assisted treatments other than methadone (buprenorphine/naloxone and naltrexone). Still, with a few notable exceptions, global drug treatment coverage for opiate injectors remains remarkably low and only a few treatment interventions for stimulant use have shown efficacy in reducing HIV risk. Importantly, more recent data provide support for the role of drug treatment programs in improving access and adherence to antiretroviral treatment and that injection drug users in substance abuse treatment are more likely to achieve sustained viral suppression. While important challenges remain in maximizing its impact, the scientific literature provides strong evidence of the efficacy of drug treatment as an HIV prevention strategy.

Increased plasmacytoid dendritic cell maturation and natural killer cell activation in HIV-1 exposed, uninfected intravenous drug users

BACKGROUND

Increased natural killer (NK) activation has been associated with resistance to HIV-1 infection in several cohorts of HIV-1 exposed, uninfected individuals. Inheritance of protective NK receptor alleles (KIR3DS1 and KIR3DL1) has also been observed in a subset of HIV-1 exposed, uninfected individuals. However, the exact mechanism contributing to NK activation in HIV-1 exposed, uninfected intravenous drug users (EU-IDU) remains to be elucidated.

OBJECTIVE

We investigated the role of both host genotype and pathogen-induced dendritic cell modulation of NK activation during high-risk activity in a cohort of 15 EU-IDU individuals and 15 control, uninfected donors from Philadelphia.

DESIGN

We assessed the activation status of NK cells and dendritic cells by flow cytometry and utilized functional assays of NK-DC cross-talk to characterize the innate immune compartment in EU-IDU individuals.

RESULTS

As previously reported, NK cell activation (CD69) and/or degranulation (CD107a) was significantly increased in EU-IDU individuals compared with control uninfected donors (P = 0.0056, n = 13). Genotypic analysis indicated that the frequency of protective KIR (KIR3DS1) and HLA-Bw4*80I ligands was not enriched in our cohort of EU-IDU individuals. Rather, plasmacytoid dendritic cells (PDC) from EU-IDU exhibited heightened maturation (CD83) compared with control uninfected donors (P = 0.0011, n = 12). When stimulated in vitro, both PDCs and NK cells from EU-IDU individuals maintained strong effector cell function and did not exhibit signs of exhaustion.

CONCLUSION

Increased maturation of PDCs is associated with heightened NK activation in EU-IDU individuals suggesting that both members of the innate compartment may contribute to resistance from HIV-1 infection in EU-IDU.

Race and distance effects on regular syringe exchange program use and injection risks: a geobehavioral analysis

OBJECTIVES

We conducted "geobehavioral" analyses by race to understand how distances among injection drug users' (IDUs') residences, drug purchase and use locations, and syringe exchange programs (SEPs) are associated with injection behaviors.

METHODS

Data were from the HIV Prevention Trial Network 037 (2002-2006) site in Philadelphia, Pennsylvania, a randomized study evaluating the efficacy of a network-oriented HIV prevention intervention for IDUs. At prescreening, participants were asked the nearest intersections to their residence, where they buy and use drugs, and about their injection behaviors.

RESULTS

Geographic distances had independent and interactive effects on injection risk behaviors and SEP use. Blacks, regardless of distance, were less likely than Whites to inject in public places (odds ratio [OR] = 0.62; 95% confidence interval [CI] = 0.43, 0.90), to use syringes after someone else (OR = 0.27; 95% CI = 0.19, 0.38), and to access syringes from SEPs (OR = 2.08; 95% CI = 1.48, 2.92). Latinos' injection behaviors were more distance-dependent than Blacks' or Whites'.

CONCLUSIONS

Distances among IDUs' homes, drug purchase and injecting sites, and prevention resources affected safe injection practices differentially by race. Understanding individuals' geographic relation to the risks and resources that surround them is an important aspect of understanding effects of the environment on health and behavior and the development of targeted interventions.

Upregulation of SOCS-3 and PIAS-3 impairs IL-12-mediated interferon-gamma response in CD56 T cells in HCV-infected heroin users

Background

CD56⁺ T cells are abundant in liver and play an important role in host innate immunity against viral infections, including hepatitis C virus (HCV) infection, a common infection among heroin abusers. We thus investigated the in vivo impact of heroin use or heroin use plus HCV infection on the CD56⁺ T cell frequency and function.

Methodology/Principal Findings

A total of 37 heroin users with (17) or without (20) HCV infection and 17 healthy subjects were included in the study. Although there was no significant difference in CD56⁺ T cell frequency in PBMCs among three study groups, CD56⁺ T cells isolated from the heroin users had significantly lower levels of constitutive interferon-gamma (IFN-γ) expression than those from the normal subjects. In addition, when stimulated by interleukin (IL)-12, CD56⁺ natural T cells from HCV-infected heroin users produced significantly lower levels of IFN-γ than those from the normal subjects. This diminished ability to produce IFN-γ by CD56⁺ T cells was associated with the increased plasma HCV viral loads in the HCV-infected heroin users. Investigation of the mechanisms showed that although heroin use or heroin use plus HCV infection had little impact on the expression of the key positive regulators (IL-12 receptors, STAT-1, 3, 4, 5, JAK-2, and TYK-2) in IL-12 pathway, heroin use or heroin use plus HCV infection induced the expression of suppressor of cytokine signaling protein-3 (SOCS-3) and protein inhibitors of activated STAT-3 (PIAS-3), two key inhibitors of IL-12 pathway.

Conclusion/Significance

These findings provide compelling in vivo evidence that heroin use or heroin use plus HCV infection impairs CD56⁺ T cell-mediated innate immune function, which may account for HCV infection and persistence in liver.

Childhood sexual and physical abuse histories, PTSD, depression, and HIV risk outcomes in women injection drug users: a potential mediating pathway

We explored links between childhood sexual abuse (CSA), childhood physical abuse (CPA), posttraumatic stress disorder (PTSD)/depression, and women injection drug users' (IDUs') risk in 113 women recruited from two syringe exchange sites. More than half (56%) reported CSA, 68% CPA, 23% likely were depressed-only, and 53% likely had PTSD/depression. CSA was associated with sexual (p = 0.003) and drug risk (p = 0.05); CPA was not. CSA was associated with PTSD/depression (p = 0.03); PTSD/depression was associated with sexual (p < 0.01) and drug (p < 0.03) risk. After PTSD/depression adjustment, CSA was no longer associated with sexual or drug risk. These results suggest that women IDUs' CSA-to-risk path is mediated by PTSD/depression.

How should HIV vaccine efficacy trials be conducted? Diverse U.S. communities speak out

Developing an effective vaccine remains a critical long-term approach to HIV prevention. Every efficacy trial should be responsive to the concerns of participating communities because the successful development of an HIV preventive vaccine will require long-term involvement of people who have been marginalized and who distrust the government and biomedical research. Using qualitative interviews and purposive sampling, we elicited recommendations regarding how vaccine efficacy trials should be conducted from 90 members of communities that have been disproportionately affected by HIV/AIDS: injection drug users, gay men, and African Americans. The most common recommendation was for complete disclosure of all aspects of the trial. Other themes included participant and community education, who to include in trials, preventing harm, trust, community involvement, researcher attributes, and respect for participants. Developing positive, respectful and collaborative experiences with community members will facilitate vaccine research because negative experiences and unfavorable community reactions can greatly impede success in future trials.

A randomized trial of audio computer and in-person interview to assess HIV risk among drug and alcohol users in Rio De Janeiro, Brazil

This study compares drug patterns and prevalence of risk behaviors in a randomized trial using two methods of administration, Audio Computer-Assisted Self-Interview (ACASI) and Interviewer-Administered Questionnaire (IAQ), among drug users seeking treatment in a drug treatment center. We randomized 735 participants: 367 to ACASI and 368 to IAQ. No significant difference in sociodemographic variables were found between subjects in the two arms of the study. Those interviewed by ACASI were more likely to report use on 7 of 10 substances assessed. Rates of reporting of sexual risk behaviors (male-to-male and commercial sex) were higher among participants in the ACASI arm. ACASI seems to be a key resource in improving the reporting of sensitive data in Brazil, as it has been in prior international studies.

Acceptability of audio computer-assisted self-interview (ACASI) among substance abusers seeking treatment in Rio de Janeiro, Brazil

This study aimed to determine the acceptability of the ACASI approach to risk assessment and the impact of personal preference regarding mode of interview on reporting risk behaviors among drug users entering treatment in Rio de Janeiro, Brazil. We assessed 268 substance users who completed the ACASI arm in a randomized trial comparing the ACASI with the Interviewer-Administered Questionnaire (IAQ). The vast majority of interviewees (90.7%) reported no problem using the computer, and 37.3% felt that their privacy was best protected by the ACASI (vs. 16.4% who preferred the IAQ). Nearly half (45.5%) reported that the computer interview would produce more "honest" answers, whereas 30.6% selected the IAQ. In the adjusted regression analysis, problems using the computer were associated only with lower educational level (p<0.05). We found no evidence that preference had an impact on reporting risk behaviors or drug use. Our study showed both good feasibility and acceptability of the ACASI for interviewing drug users in Brazil. The findings extend our understanding of the role of the ACASI method by suggesting the utility of this approach in assessing HIV risk among low-to middle-income drug users in a cultural setting quite different from previous studies.

Naltrexone inhibits alcohol-mediated enhancement of HIV infection of T lymphocytes

Acute and chronic alcohol abuse impairs various functions of the immune system and thus, has been implicated as a cofactor in the immunopathogenesis of human immunodeficiency virus (HIV) disease progression. We determined whether naltrexone, an opioid receptor antagonist widely used in the treatment of alcoholism, inhibits alcohol-mediated enhancement of HIV infection of T cells. Alcohol enhanced HIV infection of peripheral blood lymphocytes (PBL) and a human lymphoid cell line (CEMX174). Alcohol increased HIV X4 envelope (Env), not murine leukemia virus Env-pseudotyped infection of CEMX174 cells. Naltrexone antagonized the enhancing effect of alcohol on HIV infection of PBL and CEMX174 cells. The specific mu-opioid receptor antagonist, Cys2, Tyr3, Arg5, Pen7 (CTAP) amide, also blocked the enhancing effect of alcohol on HIV infection. Investigation of the underlying mechanism for the alcohol action showed that alcohol significantly increased endogenous beta-endorphin production and induced mu-opioid receptor mRNA expression in PBL and CEMX174 cells. The role of beta-endorphin in alcohol-mediated enhancement of HIV infection was indicated by the observations that naltrexone and CTAP antagonized ether alcohol- or exogenous beta-endorphin-mediated enhancement of HIV infection. These findings suggest a biological mechanism for the potential therapeutic benefit of naltrexone in treating HIV-infected alcoholics.

Morphine withdrawal enhances hepatitis C virus replicon expression

We previously demonstrated that morphine enhances hepatitis C virus (HCV) replication in human hepatic cells. Here we describe the impact of morphine withdrawal (MW), a recurrent event during the course of opioid abuse, on HCV replicon expression in human hepatic cells. MW enhanced both viral RNA and protein expression in HCV replicon cells. Blocking opioid receptors by treatment with naloxone after morphine cessation (precipitated withdrawal, PW) induced greater HCV replicon expression than MW. Investigation of the mechanism responsible for MW- or PW-mediated HCV enhancement showed that both MW and PW inhibited the expression of endogenous interferon-alpha (IFN-alpha) in the hepatic cells. This down-regulation of intracellular IFN-alpha expression was due to the negative impact of MW or PW on IFN-alpha promoter activation and on the expression of IFN regulatory factor 7 (IRF-7), a strong transactivator of the IFN-alpha promoter. In addition, both MW and PW inhibited the anti-HCV ability of recombinant IFN-alpha in the hepatic cells. These in vitro observations support the concept that opioid abuse favors HCV persistence in hepatic cells by suppressing IFN-alpha-mediated intracellular innate immunity and contributes to the development of chronic HCV infection.

Alcohol suppresses IL-2-induced CC chemokine production by natural killer cells

BACKGROUND

Natural killer (NK) cells are a critical component of the host innate immune system. We investigated whether alcohol impairs NK cell function, particularly production of CC chemokines induced by interleukin (IL)-2, the natural ligands for CCR5 receptor.

METHODS

Primary NK cells and NK cell line (YTS) were cultured with or without alcohol (10 to 80 mM) for three hours. The culture supernatants were then harvested and used to treat human peripheral blood monocyte-derived macrophages and a HeLa cell line, which expresses CD4, CCR5, and CXCR4 receptors (MAGI cells). CC chemokine expression by YTS and primary NK cells treated with or without alcohol was analyzed with the real-time RT-PCR and ELISA. [Ca(2)(+)]i and Western blot assays were used to determine calcium-mediated intracellular signaling pathway and NF-kappaB p65 expression. HIV strains (Bal and UG024) were used to infect macrophages and MAGI cells. In addition, ADA (macrophage-tropic strain) and murine leukemia virus (MLV) envelope-pseudotyped HIV infection was carried out in macrophages. HIV infectivity was determined by HIV reverse transcriptase (RT) and beta-galactosidase activity assays.

RESULTS

Alcohol inhibited IL-2-induced CC chemokine (CCL3 and CCL4) expression by NK cells. Functional tests demonstrated that this reduced expression of CC chemokines was associated with diminished anti-HIV ability of NK cells. Alcohol also reduced the ability of NK cells to response to CCL3-mediated chemotaxis. Alcohol inhibited IL-2-induced NF-kappaB p65 protein expression and calcium mobilization by NK cells.

CONCLUSIONS

Alcohol, through the inhibition of IL-2-induced NF-kappaB p65 protein expression and intracellular calcium mobilization, suppressed NK cell production of CC chemokines. This suppression of CC chemokine production was associated with diminished anti-HIV activity of NK cells. Thus, by inhibiting NK cell-mediated innate immunity against HIV, alcohol consumption may have a cofactor role in the immunopathogenesis of HIV disease.

CD8+ T cell depletion amplifies hepatitis C virus replication in peripheral blood mononuclear cells

We investigated the ability of CD8+ T cells to inhibit hepatitis C virus (HCV) replication in peripheral blood mononuclear cells (PBMCs). PBMCs isolated from 11 of 20 HCV-infected subjects had no detectable HCV RNA. Removal of CD8+ T cells from these PBMCs resulted in detection of HCV RNA, and depletion of CD8+ T cells from PBMCs that had detectable HCV RNA amplified HCV replication. Reconstitution of CD8- PBMCs with autologous CD8+ T cells led to inhibition of HCV replication. Interferon-gamma produced by CD8+ T cells was partially responsible for CD8+ T cell-mediated noncytotoxic anti-HCV activity in PBMCs. This noncytotoxic anti-HCV activity was confirmed in HCV replicon cells. Supernatants from CD8+ T cell cultures inhibited HCV RNA expression in the replicon cells. These findings may have important implications for the immunopathogenesis of HCV in both immune and hepatic cells and are relevant to the development of host innate immunity-based anti-HCV interventions.

Decreasing international HIV transmission: the role of expanding access to opioid agonist therapies for injection drug users

AIMS

To examine the role of expanded access to opioid agonist treatment as a means to decrease international HIV transmission.

DESIGN

Review of the English language literature via Medline.

MEASUREMENTS

Estimates of prevalence rates for injection drug use, HIV infection and treatment effect sizes for changes in opioid use, opioid injection, needle-sharing, injection-related HIV risk behavior and cost.

FINDINGS

An estimated 12.6 million injection drug users internationally accounted for 10% of the 4.2 million new HIV infections in 2003. Ninety-three of the 136 countries (68%) that report injection drug use identify HIV infection related to this behavior. Observational studies of methadone treatment demonstrate decreases in opioid use, opioid injection, needle-sharing and lower rates of HIV prevalence and incidence. The effectiveness of buprenorphine in demonstrating similar findings is expected, although implementations and research are still emerging. The cost-effectiveness of opioid agonist treatment has been established. The barriers to international adoption of opioid agonist treatment, despite the research evidence and international guidelines, are discussed.

CONCLUSIONS

Untreated opioid dependence leads to HIV transmission, on an international level. Opioid agonist treatments are associated with reductions in the frequency of opioid use, fewer injections and injection-related HIV risk behaviors and lower rates of HIV prevalence and incidence. Despite international recommendations, treatment for opioid-dependent injection drug users with methadone and buprenorphine is limited. Research, implementation efforts and political strategies to expand access to opioid agonist treatment are needed in order to combat the spread of HIV, especially in the developing world.

Homelessness and HIV risk behaviors among injection drug users

This article uses data from an 8-year study of injection drug users to examine whether homelessness independently influenced the likelihood of engaging in human immunodeficiency virus (HIV) risk behaviors. Fixed effects regression analyses are used to estimate the associations between four different housing contexts and four different behaviors related to transmitting HIV infections. Results showed that 16% of the study group experienced homelessness at some point during the study, and that homelessness was significantly associated with a higher likelihood of frequenting shooting galleries (odds ratio = 2.05), but did not have a significant effect on sharing syringes, sharing other injection drug paraphernalia, or participating in paid sex. These results provide limited support for positing homelessness as independently associated with increased levels of HIV-related risk behavior among injection drug users and highlights the need for more research that examines the housing dynamics among this population.

Human immunodeficiency virus prevention and the potential of drug abuse treatment

Since first recognition of the scope of the acquired immunodeficiency syndrome epidemic among the drug-using community, substance abuse treatment has been viewed as playing an important role in preventing new infections. In the past 20 years, many studies have documented significantly lower rates of drug use, drug-related risk behaviors, and human immunodeficiency virus (HIV) infections among drug users who remain in treatment programs. There is also growing evidence that drug detoxification alone is insufficient to provide protection from HIV infection. These findings have important implications for users of cocaine and noninjection drugs, as well as heroin injectors. Despite strong evidence of effectiveness and widespread support for the important public health role of drug treatment, its impact has been compromised by limited availability and acceptability. The available data clearly establish drug abuse treatment as HIV prevention, yet without expansion of existing treatment programs and the continued development of treatments for addiction to cocaine and other widely used stimulants, its public health potential cannot be realized.

HIV prevention among injection drug users: the need for integrated models

Opportunistic infections (OIs) were first recognized among injection drug users (IDUs) in New York City in 1981. By the mid-1980s, OIs had become associated with HIV infection, and attention began to focus on efforts to prevent HIV transmission among IDUs. Since then, a range of prevention strategies has been implemented and evaluated in an attempt to reduce the spread of HIV infection among drug users. These prevention strategies include (1) HIV testing and counseling and educational and behavioral interventions delivered through community outreach; (2) condom, bleach, and needle distribution and syringe access and exchange programs; (3) substance abuse treatment; and, more recently, (4) prevention interventions targeting HIV-positive IDUs. Data from evaluations of these strategies over the past 20 years have provided substantial evidence of effectiveness and have helped to inform network-based and structural interventions. Despite the cumulative empirical evidence, however, research findings have yet to be widely disseminated, adopted, and implemented in a sustained and integrated fashion. The reasons for this are unclear, but point to a need for improved communications with program developers and community planners to facilitate the implementation and evaluation of integrated intervention strategies, and for collaborative research to help understand policy, legal, economic, and local barriers to implementation.

Morphine enhances HIV infection of neonatal macrophages

Perinatal transmission of HIV accounts for almost all new HIV infections in children. There is an increased risk of perinatal transmission of HIV with maternal illicit substance abuse. Little is known about neonatal immune system alteration and subsequent susceptibility to HIV infection after morphine exposure. We investigated the effects of morphine on HIV infection of neonatal monocyte-derived macrophages (MDM). Morphine significantly enhanced HIV infection of neonatal MDM. Morphine-induced HIV replication in neonatal MDM was completely suppressed by naltrexone, the opioid receptor antagonist. Morphine significantly up-regulated CCR5 receptor expression and inhibited the endogenous production of macrophage inflammatory protein-1beta in neonatal MDM. Thus, morphine, most likely through alteration of beta-chemokines and CCR5 receptor expression, enhances the susceptibility of neonatal MDM to HIV infection, and may have a cofactor role in perinatal HIV transmission and infection.

Alcohol potentiates hepatitis C virus replicon expression

Alcohol consumption accelerates liver damage and diminishes the anti-hepatitis C virus (HCV) effect of interferon alfa (IFN-alpha) in patients with HCV infection. It is unknown, however, whether alcohol enhances HCV replication and promotes HCV disease progression. The availability of the HCV replicon containing hepatic cells has provided a unique opportunity to investigate the interaction between alcohol and HCV replicon expression. We determined whether alcohol enhances HCV RNA expression in the replicon containing hepatic cells. Alcohol, in a concentration-dependent fashion, significantly increased HCV replicon expression. Alcohol also compromised the anti-HCV effect of IFN-alpha. Investigation of the mechanism(s) responsible for the alcohol action on HCV replicon indicated that alcohol activated nuclear factor kappaB (NF-kappaB) promoter. Caffeic acid phenethyl ester (CAPE), a specific inhibitor of the activation of NF-kappaB, abolished alcohol-induced HCV RNA expression. In addition, naltrexone, an opiate receptor antagonist, abrogated the enhancing effect of alcohol on HCV replicon expression. In conclusion, alcohol, probably through the activation of NF-kappaB and the endogenous opioid system, enhances HCV replicon expression and compromises the anti-HCV effect of IFN-alpha. Thus, alcohol may play an important role in vivo as a cofactor in HCV disease progression and compromise IFN-alpha-based therapy against HCV infection.

Randomized, controlled evaluation of a prototype informed consent process for HIV vaccine efficacy trials

Procedures must be developed to ensure that valid informed consent is obtained from participants in HIV vaccine efficacy trials. A prototype informed consent process was evaluated among 4,892 persons at high risk for HIV infection in the HIV Network for Prevention Trials Vaccine Preparedness Study (VPS), a prospective cohort study of HIV seroincidence in eight U.S. metropolitan areas. Twenty percent of VPS participants were selected at random to undergo the prototype informed consent process at VPS month 3. Participants' knowledge of 10 key HIV vaccine trial concepts and willingness to participate in HIV vaccine efficacy trials were assessed and compared at baseline and semiannually thereafter for 18 months. Knowledge of HIV vaccine trial concepts was low at baseline. Participation in the prototype process was associated with substantial and sustained increases in knowledge (relative risks for the 10 items, 1.04-2.26), which were of similar magnitude across HIV risk groups, race/ethnicity, and educational levels. It is recommended that the prototype informed consent process be adopted for future HIV vaccine efficacy trials as well as for clinical trials in other research areas.

Alcohol potentiates HIV-1 infection of human blood mononuclear phagocytes

BACKGROUND

Acute and chronic alcohol abuse impairs various functions of the immune system and thus has been implicated as a cofactor in HIV infection. The mechanisms by which alcohol affects the function of human immune cells that are the targets for HIV are unknown.

METHODS

Human blood monocyte-derived macrophages (MDM) were incubated with or without alcohol (10-40 mM) for 24 hr and then infected with HIV for 24 hr. Culture supernatants were harvested for HIV reverse transcription assay. HIV entry receptor (CCR5, CD4, and CXCR4) expression was determined by reverse transcription-polymerase chain reaction and flow cytometry assays. Beta-chemokines were analyzed using enzyme-linked immunosorbent assay. Different HIV strains (Bal, SF-162, 89.6, and UG024) were used for infection experiments. In addition, ADA (macrophage-tropic strain) and murine leukemia virus envelope-pseudotyped HIV infection was carried out.

RESULTS

Although alcohol had little effect on HIV T-lymphocyte-tropic strain infection, it significantly enhanced HIV R5 strain infection in MDM. The enhancing effect of alcohol on the HIV R5 strain was further evidenced by the observation that the R5 (ADA) strain envelope-pseudotyped HIV infection is markedly increased by alcohol, whereas murine leukemia virus envelope-pseudotyped HIV infection was not affected. Alcohol significantly up-regulated CCR5 receptor expression and inhibited the endogenous production of beta-chemokines by MDM.

CONCLUSION

Alcohol, through the down-regulation of beta-chemokine production and the up-regulation of CCR5 receptor expression, enhances HIV R5 strain infection of MDM and may have an important role as a cofactor in the progression of HIV disease.

What is community? An evidence-based definition for participatory public health

Increased emphasis on community collaboration indicates the need for consensus regarding the definition of community within public health. This study examined whether members of diverse US communities described community in similar ways. To identify strategies to support community collaboration in HIV vaccine trials, qualitative interviews were conducted with 25 African Americans in Durham, NC; 26 gay men in San Francisco, Calif; 25 injection drug users in Philadelphia, Pa; and 42 HIV vaccine researchers across the United States. Verbatim responses to the question "What does the word community mean to you?" were analyzed. Cluster analysis was used to identify similarities in the way community was described. A common definition of community emerged as a group of people with diverse characteristics who are linked by social ties, share common perspectives, and engage in joint action in geographical locations or settings. The participants differed in the emphasis they placed on particular elements of the definition. Community was defined similarly but experienced differently by people with diverse backgrounds. These results parallel similar social science findings and confirm the viability of a common definition for participatory public health.

Who will enroll? Predicting participation in a phase II AIDS vaccine trial

BACKGROUND

The problems of underenrollment and selective enrollment may undermine AIDS vaccine trials. If prospective study subjects' stated willingness to participate (WTP) in hypothetical vaccine trials predicts future enrollment, then measuring WTP before recruitment may enhance the enrollment in, and ethics of, such trials.

METHODS

We prospectively studied changes over an 18-month period in the stated WTP in, and knowledge of, a hypothetical AIDS vaccine trial among 610 Philadelphia residents at high risk for HIV infection. Of these people, 499 were subsequently recruited to participate in an actual, phase II AIDS vaccine trial. We used multivariable logistic regression and the area under the receiver-operating characteristic (ROC) curve to model predictors of actual enrollment.

RESULTS

Actual enrollment rates were 8.3%, 6.8%, 15.8%, and 29.0% among those who had initially said they were "definitely not," "probably not," "probably," and "definitely" willing to participate, respectively (p =.006). The area under the ROC curve was 0.65, indicating a modest ability of stated WTP to differentiate those who enroll from those who do not. Knowledge of basic vaccine trial concepts, though unrelated to enrollment, increased over an 18-month period with repeated education sessions (p <.0001), whereas stated WTP declined over this same period (p <.0001).

CONCLUSION

Although other factors not captured by stated WTP may also influence future enrollment, prospectively assessing stated WTP may augment the validity of the informed consent process, help prevent underenrollment, and clarify the population from which the study sample is drawn.

Determinants of risk behavior for human immunodeficiency virus/acquired immunodeficiency syndrome in people with severe mental illness

We examined the prevalence and correlates of human immunodeficiency virus (HIV)/acquired immunodeficiency syndrome (AIDS) risk behaviors in a large sample of severely mentally ill (SMI) patients. Risk levels were correlated with demographic factors, diagnosis, symptom severity, trauma history, post-traumatic stress disorder (PTSD), substance use disorder (SUD), and sexual orientation. SMI clients from urban and rural settings (N = 275) were assessed regarding HIV/AIDS risk behaviors, and hypothesized risk factors. Patients exhibited substantial levels of risky behavior, particularly sexual risk. Correlates of increased risk included SUD, trauma, male homosexual orientation, younger age, and symptom severity. Structural equation modeling identified SUD and sexual orientation as the primary determinants of both drug and sexual risk behavior. We conclude that specific illness related variables appear to have less impact on risk behavior among people with SMI than previously hypothesized. Substance abuse prevention and treatment may be the most effective means of reducing HIV risk in this population.