Definition of the Prevention Area
A "structural approach” to HIV prevention is the process of selecting a set of interventions that use structural factors to reduce HIV risk at the individual and/or group level. Structural factors are elements outside individual knowledge or awareness that have the potential to influence people’s vulnerability to HIV infection. They include social (e.g., stigma, gender inequality); legal-political (e.g., laws and regulations); cultural (e.g., religious beliefs); and economic (e.g., lack of livelihood opportunity) factors.
Structural factors fall into two conceptual categories:
- Risk drivers: Factors that have been empirically shown to shape patterns of risk behavior in particular populations.
- Environmental mediators: Increase people’s resilience to HIV (PDF, 1.23 KB) or hinder their ability to avoid HIV in a particular context (e.g., laws that criminalize and drive underground men who have sex with men, limiting their ability to seek HIV-prevention services.)
Epidemiological Justification for the Prevention Area
There is a growing body of quantitative and qualitative evidence linking structural factors to HIV risk and its proximate determinants (e.g., multiple sexual partnering and lack of condom use). Given the complex and numerous pathways between structural factors and HIV transmission, however, few structural programs have been evaluated for their impact on HIV incidence.
Most of the emerging evidence centers on a few factors, including gender inequality, stigma and discrimination, economic empowerment and livelihood opportunities, education, and alcohol. For each of these factors, there is evidence on the impact of interventions that target them, although the relative importance of particular structural factors varies across settings.
One randomized controlled trial (RCT) that linked structural factors with HIV biomarkers found significantly lower levels of HIV and HSV-2 among Malawian schoolgirls who received monthly cash payments than among those who did not receive the payments. In Kenya, a study showed that reducing the cost of primary education by paying for school uniforms reduced dropout rates, teen marriage, and childbearing—all factors closely related to HIV risk. Other HIV-prevention programs have addressed structural factors by changing gender and violence against women norms, supporting micro-credit programs, and strengthening the legal rights of underserved populations. A recent Journal of the International AIDS Society supplement discusses the necessity of addressing these and other structural factors in future HIV investments. Service models should be adapted to the economic and social environments of clients, and HIV programming incorporated into wider gender and development efforts.
Core Programmatic Components
There is now widespread agreement that structural approaches are a critical part of a “combination HIV-prevention” strategy. In addition to the positive outcomes that structural interventions can achieve on their own, they are important to the success of biomedical and behavioral interventions. For example, voluntary medical male circumcision provision programs may not realize potential impact without including activities that address structural factors, such as socio-cultural norms that influence men and women’s circumcision (PDF, 1.18 MB) preferences and mobility-constraining poverty that may limit certain populations’ access to services.
There is no “one size fits all” structural approach that is appropriate for all epidemics, settings, or target populations. A defining component of a structural approach to HIV prevention is choosing a set of interventions according to evidence-informed analysis of the particular characteristics of the target population, the context, and the risk drivers and environmental mediators of HIV in a specific setting. For example, in a setting where migratory labor is common and laborers have high levels of HIV, a structural approach might include workplace HIV-prevention (PDF, 444 KB) or an intervention to create alternative economic opportunities. In an epidemic where HIV is transmitted primarily through sex work, a priority intervention could focus on persuading local authorities to enforce condom use in brothels.
Although there is no single approach for all settings, the following considerations and features are characteristic of good structural programming and should be addressed in the development and implementation of structural approaches in any setting:
- Clear articulation of the causal pathway between the structural factor and HIV risk, and where along the pathway the intervention aims to have impact.
- Understanding of the intervention’s possible unintended effects.
- Definition of the macro (national/regional), meso (community), and/or micro (individual/family) levels that the intervention expects to influence.
- Attention to the needs of marginalized and/or hard-to-reach groups.
These considerations are delineated in the AIDSTAR-One Structural Resource tool.
Current Status of Implementation Experience
Structural interventions are not new to public health prevention strategies. Well-known and successful examples include increasing taxes to reduce or prevent smoking and national programs to put fluoride into drinking water to prevent tooth decay. In the HIV arena, however, the importance of structural interventions has only recently garnered significant attention. There is no consensus on key concepts, definitions, what works, or the causal pathways that help programs succeed. This is in part due to gaps in the evidence base, many of which result from the technical challenges of measuring the impact of structural programming. The position paper series developed by AIDSTAR-One and STRIVE makes progress, providing definitions for key structural HIV-prevention concepts, analysis of the current evidence base and gaps, frameworks for approaching structural prevention, and lessons from field-based implementation experience.
Measuring the effectiveness of structural intervention programs can be difficult for several reasons:
- There is no direct, one-to-one relationship between structural interventions and HIV incidence.
- Structural interventions are not often amenable to randomization.
- Causal pathways from intervention to end point outcomes are usually indirect and complex.
- Funding to study these questions at scale is not proportionate with funding for research on biomedical and behavioral interventions.
Existing evaluations of the effect of structural interventions on HIV and proximal behavioral outcomes use multiple, diverse methodologies to allow triangulation of data. Methodologies include RCTs (PDF, 104 KB), quasi-experimental studies, and qualitative studies (PDF, 377 KB). Retrospective studies of broad national responses to the epidemic have combined sources and methods typically used in public health (e.g., HIV prevalence and incidence modeling, behavioral and demographic health survey data, interview and focus group data, and condom shipment data), with infrequently used (PDF, 78 KB) (i.e., newspaper reports of behavior change) methods. Limitation to conventional methods may undercut the development of new and effective HIV-prevention approaches. Researchers have called for further engagement with social science methods and the use of combinations of data from different types of evaluations, as well as careful inclusion of less rigorous sources to make progress in generating an evidence base.