Substance Use Research Strategy

Overview

While declines in HIV/AIDS incidence and mortality have occurred in several developed countries, HIV transmission among injecting drug users (IDUs) and other drug users remains an urgent and expanding public health problem in many regions of the world. In fact, the majority of new HIV infections in Eastern Europe, Russia, and South East Asia are attributable to injection-related risk behaviors. Rapid HIV transmission among IDUs in low prevalence settings is leading to new epidemics in many countries. Thus, there is significant epidemiologic relevance to prevention efforts targeting IDUs. The mechanisms of transmission are reasonably clear, although new drugs and contexts arise, especially in international settings, and need to be investigated for formulating and tailoring interventions.

The Substance Use Scientific Committee's scope of work includes:

		Preventing transmission through injection drug use and sexual transmission of HIV among injection and non-injection substance users (e.g., alcohol, crack cocaine, and other non-injection drugs)
		Developing and refining primary and secondary prevention interventions for HIV-infected drug users
		Evaluating interventions designed to overcome structural and community level barriers to accepting and implementing effective HIV prevention strategies

Background and Rationale

	Persons using illicit drugs, especially by the parenteral route, are at high risk for HIV infection. Numerous studies have been conducted on IDUs, and it is clear that multi-person reuse of needles and syringes represents a primary mechanism for HIV transmission. Sharing drug preparation equipment and injection equipment, either directly or indirectly, results in higher risk of infection.
	Sexual transmission and related risk behaviors, including exchange of sex for drugs or money, have been independently associated with HIV infection among injection and non-injection drug users.
	Individuals who participate in effective treatments for substance abuse reduce the frequency of their drug use, which reduces the incidence of drug related risk behaviors.  In turn, lower rates of drug related risk behaviors result in fewer exposures to HIV and fewer infections.
	Interventions known to be effective in reducing HIV risk behaviors involve community outreach, access to sterile syringes, and drug abuse treatment.
	Structural interventions and those that target communities and the social networks of drug users are considered to be of the highest priority.

In 1997, the NIH Consensus Development Conference on HIV Prevention summarized effective approaches to use with IDUs, based on behavioral and biological outcomes. The primary approaches include community outreach (including indigenous outreach leaders), needle exchange, and drug abuse treatment (including methadone).  While studies using behavioral outcomes are numerous, data on HIV seroconversion as an outcome are few, and none have been the result of a randomized clinical or community trial. Given the many reports that show these interventions are effective, the ethical considerations of a randomized design need to be carefully weighed and considered (e.g., comparing different methods is more acceptable than a no-treatment arm). 

While considerable published research demonstrates the efficacy of needle exchange programs, and government sponsored reports in the U.S. and elsewhere have acknowledged the science exists to support implementation of the interventions, many communities have been reluctant to accept such programs as part of a comprehensive HIV prevention program. Only a few states have followed the lead of Connecticut and put in place laws that permit pharmacy access to syringes and needles; recently such a law has been enacted in New York.  While HPTN studies are not able to directly fund needle exchange components, the Substance Use Scientific Committee is intent on designing studies that are linked to programs that provide access to sterile injection equipment.   

 Key public health questions to be addressed

	What are the most effective behavioral approaches that are theory-driven (using cognitive-behavioral, affective, peer outreach, network/support group or hybrid strategies) directed at both drug and sex-related risk behaviors?
	How can behavior change strategies be paired with biomedical approaches (treatment of STDs, use of microbicides and drug treatment) to reduce sexual transmission of HIV and drug related risk behaviors?
	What is the best approach or combination of approaches to implementing social/environmental programs that incorporate needle exchange to reduce parenteral transmission, syringe exchange programs, pharmacy sales, physician prescription, and/or improving access to other HIV prevention services, and modifying drug abuse treatment to optimize access/adherence to reduce parenteral transmission?
	How will the changing nature of the HIV epidemic among drug users effect the implementation of interventions in such areas and in countries where potential biomedical drug treatments are illegal?
	Can an intervention targeting HIV infected IDUs to serve as peer leaders among their IDU network result in a reduction on HIV seroincidence?
	Can interventions targeting the sexual transmission of HIV among drug using individuals reduce incidence and limit the "bridging" of HIV to non-drug using populations?

HPTN Substance Use Studies

HPTN Substance-use Scientific Committee Contacts

Dave Metzger, Chair, University of Pennsylvania
Bonnie Dye, Family Health International
 

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