Definition of the Prevention Area
In 2009, The U.S. President’s Emergency Plan for AIDS Relief (PEPFAR): Five Year Strategy defined combination prevention as its major approach to HIV prevention, stating that:
"Successful prevention programs require a combination of evidence-based, mutually reinforcing biomedical, behavioral, and structural interventions."
This definition was expanded upon in a 2009 meeting of the Joint United Nations Programme on HIV/AIDS (UNAIDS) Prevention Reference Group and published in the 2010 UNAIDS Discussion Paper on combination prevention, in which combination programming was defined as:
"...rights-based, evidence-informed, and community-owned programmes that use a mix of biomedical, behavioural, and structural interventions, prioritized to meet the current HIV prevention needs of particular individuals and communities, so as to have the greatest sustained impact on reducing new infections."
Epidemiological Justification for the Prevention Area
The goal of combination prevention is to reduce the transmission of HIV by implementing a combination of behavioral, biological, and structural interventions that are carefully selected to meet the needs of a population. Also, because individuals’ HIV prevention needs change over a lifetime, combination approaches help ensure that people have access to the types of interventions that best suit their needs at different times. Practitioners and researchers currently believe that combination approaches result in synergies in which the total effect of a set of carefully chosen interventions is greater than the sum of its parts, with a greater impact on reducing the transmission of HIV. This hypothesis, however, remains to be proven.
Prevention programmers have used various models to attempt to identify the drivers of the epidemic, provide a guide on which mix of interventions would have the greatest impact, and give strategic choices on combination prevention approaches.
Others caution against the use of models in making strategic prevention decisions, since models may provide outputs that fail to identify the key behaviors that drive an epidemic, and are difficult to fit to local epidemics that are heterogeneous across different locations. Therefore, models are a tool that should always be used in conjunction with other data sources to make programmatic decisions.
Core Programmatic Components
In August 2011, PEPFAR issued Guidance for the Prevention of Sexually Transmitted HIV Infections, and recommends a combination approach to prevention that includes three types of mutually reinforcing interventions:
- Biomedical interventions are those that directly influence the biological systems through which the virus infects a new host: for example, by blocking infection (e.g., male and female condoms), decreasing infectiousness (e.g., antiretroviral therapy as prevention), or reducing acquisition/infection risk (e.g., voluntary medical male circumcision).
- Behavioral interventions include a range of sexual behavior change communication programs that use various communication channels (e.g., mass media, community-level, and interpersonal) to disseminate behavioral messages designed to encourage people to reduce behaviors that increase risk of HIV and increase protective behaviors (e.g., risks of having multiple partners and benefits of using a condom correctly and consistently). Behavioral interventions also are aimed at increasing the acceptability of and demand for biomedical interventions.
- Structural interventions address the critical social, legal, political, and environmental enablers that contribute to the spread of HIV. PEPFAR describes structural interventions in terms of five categories addressing: legal and policy reform; stigma and discrimination against people living with HIV and marginalized groups; gender inequality and gender-based violence; economic empowerment and other multi-sectoral approaches; and education.
The PEPFAR guidance goes into further detail on which core interventions (i.e., programs for prevention of mother-to-child transmission, voluntary medical male circumcision, condom promotion, and key populations and people living with HIV) should be prioritized and implemented based on UNAIDS’ “Four Knows,” (based on the principle "know your epidemic, know your response." The Four Knows bases selection and scale of interventions on epidemiological evidence, country context, knowledge of other donor programs, and national strategies. Additionally, prevention strategies should be assessed through impact evaluations.
To achieve this, programmers should perform a gap analysis in their countries to determine which key drivers, geographical locations, and range of interventions are lacking; and then include those in their prevention portfolio to try and create synergy among them. To implement the interventions that would be most effective in the country’s context, the questions to ask when making prevention portfolio decisions are, “How much, when, and where?”
Current Status of Implementation Experience
Although the term “combination prevention” is relatively new, the concept itself is not. Countries experiencing HIV epidemics routinely implement complex packages of prevention interventions; yet the scale, intensity, and quality of these interventions is often insufficient. Furthermore, only a minority of programs include interventions designed to address structural drivers of the epidemic. Complex and successful programs have existed for some time in concentrated epidemics where service packages include biomedical, behavioral, and structural interventions; however, these approaches remain under-implemented and under-evaluated. Often, prevention portfolios are not adequately focused on the populations and behaviors that actually drive the epidemic, nor are they sufficiently well implemented in the locations where the risk behaviors are most likely to occur. Interventions need to be chosen based on the complexity of behaviors within populations, as well as how social and cultural norms influence sexual and health-seeking behaviors. However, current combination prevention programs are building on lessons learned and improving strategies to increase their impact on the epidemic.
A number of countries are implementing combination prevention packages, including Botswana, India, Namibia, South Africa, and Uganda. Combination prevention is a portfolio approach for a given geographic area—whether at the national, state, district, or community level. It is not an individual implementing a partner-level approach, but involves a number of partners who contribute towards a combination prevention approach. Modeling can be used as a tool to identify the most cost-effective package of prevention interventions for different populations and in different settings.