Director's Report to the National Advisory Council on Drug Abuse
February, 1996
Research Findings
AIDS Research
Maternal Antibodies in HIV-Uninfected Infants
Savita Pahwa and associates discovered the presence of human immunodeficiency virus (HIV)-specific maternal antibodies bound to the peripheral blood mononuclear cells (PBMCs) of 39 uninfected infants born to HIV-infected women. Such antibodies were not observed on PBMCs of 13 infants in whom maternal-child transmission of HIV had occurred. These results suggest that PBMC-bound maternal antibodies might have a protective role in the transmission of HIV from mothers to infants. Pediatric Research 38: pp. 384-389, 1995.
Needle and Syringe Acquisition and Use among IDUs
A study of the acquisition and use of needles and syringes by IDUs was undertaken among a cohort of active injectors in Baltimore, MD prior to the opening of a needle exchange program. Among both HIV positives and negatives, less than one quarter (22%) had participated in a detoxification or methadone treatment program in the prior 6 months. The majority of respondents reported injecting at least once per day (56%). Usual sources of needles and syringes reported by 466 IDUs (95% Black, 83% male) included: street dealers (50%), pharmacies (30%), diabetics (16%), friends/neighbors (2.2%), and shooting galleries (2%). Twenty-three percent reported trading drugs and 5% reported trading sex for needles and syringes. Needle syringe reuse was common (median 3 times). Approximately 88% reported that they would use a needle exchange if it were available. These data will be used to assess the impact of the Baltimore City Health Department needle exchange program now in operation. Gleghorn, A., Jones, T.S., Doherty, M.C., Celentano, D.C., & Vlahov, D. Acquisition and Use of Needles and Syringes by Injecting Drug Users in Baltimore, Maryland. JAIDS, 10: pp. 97-103, 1995.
Maintaining Low HIV Seroprevalence in Populations of Injecting Drug Users
Don Des Jarlais, Holly Hagan, Samuel Friedman, and their associates developed case histories of five cities in which HIV has been introduced into a heterosexual IDU community but where HIV seroprevalence has remained low and stable. The case studies were conducted to identify common elements of prevention in the communities that could serve as models for other communities with similar HIV/IDU profiles. Three common prevention components were identified (beginning early, community outreach, and access to sterile injection equipment). The authors conclude that, in low seroprevalence areas, it appears possible to severely limit transmission of HIV among populations of IDUs, despite continuing risk behavior among a substantial proportion of the population. They recommend the implementation of the three prevention elements wherever populations of IDUs are at risk for rapid spread of HIV. JAMA, 274: pp. 1226-1231, 1995.
Risk Factors for HIV among Out-of-Treatment IDU in High and Low Seroprevalence Cities
NIDA grantees of the National AIDS Research Consortium, including Samuel R. Friedman, Benny Jose, Sherry Deren, Don C. Des Jarlais, and Alan Neaigus, report findings from their research to determine significant predictors of HIV seroconversion in 10 low seroprevalence and five high seroprevalence cities in the U.S. The Consortium interviewed and collected serum samples from 6,882 IDU in the 15 U.S. cities from 1988 to 1991. Significant predictors of seroconversion in the low seroprevalence cities were: not being in treatment, injecting in outdoor settings or abandoned buildings, using crack cocaine weekly or more frequently, engaging in woman-to-woman sex, being of other than Latino race/ethnicity, and city seroprevalence. Predictors in high seroprevalence cities were injecting with potentially infected syringes, not being in drug treatment, and having a sex partner who injected drugs. The authors suggest that HIV may be concentrated in sociobehavioral pockets of infection in low seroprevalence cities. For reducing HIV transmission in these cities, they recommend localized monitoring to detect specific emerging sociobehavioral pockets of infection and quick implementation of targeted interventions. For high seroprevalence cities, they recommend more emphasis on locality-wide outreach and syringe exchange.
For both types of cities, the authors prescribe broad expansion of drug treatment programs. Am J Epidemiol., 42: pp. 864-874, 1995.
HIV Incidence Among New Haven Needle Exchange Participants: Updated Estimates from Syringe Tracking and Testing Data
Drs. Edward Kaplan and Robert Heimer of Yale University provide updated estimates of the rate of new HIV infections among participants in New Haven's legal needle exchange program from syringe tracking and testing data. These researchers had previously reported that, based on data collected from 1990 to 1992, the maximum likelihood incidence rate was zero with a 95% confidence interval of 0-10.2 new infections per 100 drug injectors per year. Expanding this data set through 1993, the same statistical methods yield a maximum likelihood estimate of 1.63 new infections per 100 drug injectors with a 95% confidence interval of 0-7.2. Given these data, the authors conclude that the null hypotheses of no new infections cannot be rejected, lending support to the efficacy of the New Haven needle exchange program. J AIDS and Human Retrovirology. 10: pp. 175-176, 1995.
Networks of IDUs
Carl Latkin, Wallace Mandell, David Vlahov, and others at Johns Hopkins University examined social contextual factors antecedent to needle sharing in a sample of inner-city drug users in Baltimore, Maryland. Drug users' social context was assessed through an analysis of personal networks. Each of the 330 individuals participating in the research were interviewed twice at 5 months apart. The authors report that higher total personal network density and larger drug network size were positively associated with reports of sharing needles and that attending shooting galleries was positively associated with size of positive feedback network and negatively associated with size of material aid network. The data suggest that needle sharing and injecting in shooting galleries are influenced by ecological and resource factors. The findings also demonstrate the potential utility of network-oriented strategies for reducing needle sharing among IDUs. Social Networks, 17: pp. 219-228, 1995.
Risk Factors for HIV-1 Seroconversion Among Injection Drug Users (IDUs)
Dale Chitwood, Bryan Page, Clyde McCoy, and others at the University of Miami School of Medicine conducted a case-control study in Miami to identify risk factors associated with HIV seroconversion among IDUs. Using data collected from two longitudinal cohorts of IDUs, the authors identified the sharing of injection equipment to be the single best independent risk factor for seroconversion in both groups. A marginal risk factor was the presence of a sexually transmitted disease during the time of the study. The authors conclude that both an injection and a sexual component play a role in HIV seroconversion among IDUs, although the injection component appears to be much stronger. Am J Public Health, 85: pp. 1538-1542, 1995.
Outcomes of a Risk-Reduction Intervention with High-Risk Populations: The Harlem AIDS Project
Sherry Deren, Rees Davis, Mark Beardsley, Stephanie Tortu, and Michael Clatts of the National Development and Research Institute compared outcomes of risk reduction interventions with high risk populations in Harlem, N.Y. About 1,770 IDUs and their sex partners were randomly assigned to two interventions and assessed at repeated intervals. IDUs who participated in either of the interventions or in the non-intervention ("control") were found to have significant reductions in risk behaviors. However, the authors describe the risk characteristics of persons lost to follow up (i.e., more likely to be homeless, to be non-Latino, and to use shooting galleries) and point out the importance of assessing outcomes for all types of participants, including those lost to follow up. They also discuss the need to distinguish the impact of interventions from other explanations for behavior change. AIDS Education and Prevention,7(5): pp. 379-390, 1995.
Use of the Health Belief Model to Predict HIV Needle Risk Practices
Russel Falck, Harvey Siegal, Jichuan Wang, and Robert Carlson of the Wright State University School of Medicine examined the usefulness of specific dimensions of the Health Belief Model (HBM) for predicting HIV needle risk practices among 118 active IDUs, many of whom also used crack cocaine. Two health beliefs (self-efficacy and perceived susceptibility) were significantly related to safer injection practices. Other predictors of safer injection behavior were being African-American and injection frequency. The authors conclude that the Health Belief Model does have a substantive role to play in risk reduction programs that target IDUs. AIDS Education and Prevention, 7(6): pp. 523-533, 1995.
Reliability of Self-Reported HIV Risk Behaviors of Drug Users
Richard Needle and Helen Cesari of NIDA, in collaboration with Barry Brown and grantees in the NIDA-sponsored Cooperative Agreement for AIDS Community-Based Outreach and Intervention Research Program, examined the test-retest reliability of NIDA's Risk Behavior Assessment (RBA) questionnaire by analyzing reported HIV risk behaviors among drug users. The RBA, a structured-interview questionnaire, was administered twice to 196 drug users in five cities over a 48-hour period. The findings indicated that respondents consistently self-report drug use, injection practices, and sexual behaviors. Discrepant reports do not appear to reflect systematic decreases or increases in self-report. Rather, unreliability was found to be associated with poorly worded questions and respondent characteristics. The authors discuss the implications of measurement error for estimating risks, understanding relationships between behavior and HIV transmission, and interpreting change after interventions. They have since revised the low reliability items in the RBA and are currently examining whether the revisions result in improved reliability. Psychology of Addictive Behaviors, 9(4): pp. 242-250, 1995.
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