Prevention
Combination Prevention Approach | Priority Prevention Interventions | Technical Resources
The world has reached an important turning point in HIV prevention. New HIV infections continue to fall, and new prevention tools are becoming available. As Secretary Hillary Clinton noted in a landmark speech in November 2011 at the National Institutes of Health, the world now has “a historic opportunity... to change the course of this pandemic and usher in an AIDS-free generation.” The Secretary highlighted the need to put into action new knowledge regarding scientifically proven prevention tools and to scale them up in concert with one another and other supportive prevention interventions.
Still, preventing new HIV infections remains both the highest priority and the greatest challenge in the fight against HIV and AIDS. Globally, 2.7 million new HIV infections occurred in 2010, more than 70 percent in sub-Saharan Africa. The number of new infections continues to outpace the number of patients initiating antiretroviral treatment, underscoring the urgent need to strengthen prevention efforts. Significantly reducing new infections would make it possible to treat more people than are becoming infected each year and sustain the future expansion of life-saving HIV treatment. Moreover, since antiretroviral therapy (ART) has been shown to reduce HIV transmission, the scale-up of treatment itself is emerging as a key HIV prevention intervention.
Prevention strategies need to be tailored to the particular epidemic setting, since HIV epidemics differ fundamentally in terms of the populations affected and the main drivers and sources of transmission, e.g., who gets infected and how. HIV epidemics can be categorized broadly into the following three main types.
- Generalized epidemics, where transmission occurs largely among the general population. These epidemics are mostly limited to sub-Saharan African countries with adult HIV prevalence between 5 percent and 26 percent. Key epidemic drivers include widespread multiple and concurrent sexual partnerships, low rates of condom use, and low rates of male circumcision. Another important source of transmission in these epidemics is between HIV-positive persons and their uninfected spouses or long-term partners.
- Concentrated epidemics, where transmission occurs primarily among most-at-risk populations (MARPs), i.e., persons engaged in sex work, men who have sex with men, or people who inject drugs. These epidemics are found throughout Asia, Europe, Latin and North America, North Africa, and the Middle East. Typically, less than 1 percent of the adult population is HIV infected in these settings.
- Mixed epidemics, where transmission is sustained both in MARPs and among the general population. Mixed epidemics exist primarily in West and East Africa and the Caribbean region with adult HIV prevalence ranging between 2 percent and 5 percent.
Additionally, transmission from HIV-positive mothers to their infants during pregnancy, delivery, or breastfeeding contributes about 14 percent of new infections globally and is the leading source of child HIV infections. Prevention of mother-to-child transmission (PMTCT) is thus a critical element of most HIV prevention programs.
Importantly, HIV infection rates appear to have been declining in a growing number of countries. According to UNAIDS, over the past decade,new infections have fallen by more than 25 percent in 33 countries, including 22 in sub-Saharan Africa. These declines in national prevalence appear to reflect both population-level reductions in risk behaviors, especially numbers of sexual partners, and the natural course of the epidemic. Among generalized epidemics, prevention successes have been observed in Uganda, Cote d’Ivoire, Kenya, urban Malawi, Zambia, and Zimbabwe, among other countries. Cambodia, India, and Thailand are countries with concentrated epidemics where HIV rates have declined as a result of programs focused on populations at higher risk of exposure to HIV. In particular, these countries have improved availability and promoted the use of condoms within the context of sex work. Despite these successes, HIV rates in many countries remain unacceptably high, making prevention a paramount priority.
USAID's Combination Prevention Approach
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As a key partner agency in the U.S. President’s Emergency Plan for AIDS Relief (PEPFAR), USAID currently supports a “combination prevention” approach to prevention, in alignment with PEPFAR prevention guidance as well as the latest expert thinking. “Combination prevention” refers to a package of linked evidence-based behavioral, biomedical, and structural interventions, strategically tailored for maximum impact on HIV transmission in a specific country context or with a specific population. A combination approach is important because at present, no single intervention is 100 percent protective against HIV or has proven sufficient by itself to reduce population-level incidence. Behavioral, biomedical, and structural approaches work in complementary ways, and modeling suggests synergies across these approaches can magnify the overall prevention impact. These categories are not mutually exclusive; in particular, biomedical interventions often rely on behavioral components for their uptake and success. USAID, with more than 50 years of experience implementing large-scale, complex, community-based public health and development projects, has a particular focus on taking combination prevention to scale in low-resource settings.
Behavioral interventions reduce exposure through education and skills building and by changing social norms to minimize risk behaviors or increase protective behaviors. Behavioral interventions also optimize biomedical prevention modalities by creating demand for services and products and promoting adoption of safer sexual behaviors, in conjunction with biomedical activities. USAID has been a leader globally in behavioral prevention for both youth and adults in generalized epidemics and in the scale-up of behavioral interventions targeted to MARPs.
Biomedical interventions use medical technologies to block infection, decrease infectiousness, or reduce biological susceptibility. They include voluntary medical male circumcision (VMMC); male and female condoms; antiretroviral drug-based prevention, including PMTCT, post-exposure and pre-exposure prophylaxis; and activities to promote blood and injection safety. USAID was an early advocate for VMMC and has been a pioneer in scaling up both VMMC and PMTCT. USAID also is deeply engaged in research on emerging biomedical technologies, including topical microbicides and the search for an HIV vaccine.
Structural interventions aim to modify the context in which people live in order to reduce their vulnerability to HIV, especially by addressing more “distal” determinants beyond the individual locus of control. Structural approaches are the least developed intervention category, but they are likely critical for a comprehensive, sustainable HIV response. They encompass changing gender norms that contribute to HIV risk, enhancing educational and economic opportunities, political leadership, and policy and legal reform. Structural approaches offer opportunities for USAID to leverage its broader development efforts in education, democracy and government, and economic growth.
Priority Prevention Interventions |
Voluntary medical male circumcision (VMMC) - VMMC has been shown to reduce men’s risk of HIV by 60 percent. USAID supports scaling up a comprehensive VMMC package for HIV/AIDS prevention in 14 PEPFAR priority countries with high HIV prevalence and low rates of male circumcision. USAID assists countries in response to requests from host governments and in alignment with their national policies, guidelines, and cultural norms. |
| Preventing mother-to-child transmission of HIV -Existing technologies have virtually eliminated mother-to-child transmission in developed countries. USAID is working to increase the uptake of these technologies in low-resource settings by scaling up basic antenatal care; improving access to HIV testing and counseling (HTC), ART prophylaxis and treatment, family planning, and safe delivery; as well as counseling and support for safer infant feeding. |
| Male and female condoms - Scientific studies have demonstrated that the correct and consistent use of male latex condoms reduces the likelihood of HIV infection by 80 percent to 90 percent. USAID is the largest donor of condoms worldwide, providing roughly 40 percent of donor-supported condoms. USAID also supports strengthening of logistics and distribution systems and promotes innovative private sector and social marketing approaches to promote increased use of condoms. |
| Comprehensive services package for most-at-risk-populations (MARPs) - Across all types of epidemics, individuals who engage in certain socially stigmatized risk behaviors are at disproportionately higher risk of contracting HIV. USAID is a global leader in providing these hard-to-reach and marginalized populations with a comprehensive package of prevention services. |
| Behavioral prevention - Behavior change, especially partner reduction, has played a key role in all generalized epidemics where declines in HIV rates have occurred. USAID, with its strong links to community programming, has supported social mobilization and individual-level behavioral interventions, with help from the mass media, to promote partner reduction, condom use, delay of first sex, and uptake of HIV services in dozens of countries, likely contributing to the declines in HIV seen in many countries. |
HIV counseling and testing -HIV testing and counseling is a crucial gateway to HIV care and treatment, prevention for persons living with HIV/AIDS and their partners and families, and biomedical prevention modalities such as PMTCT. USAID supports the scale-up of a range of HTC service delivery models for different populations and contexts while also contributing to the international knowledge base on methodologies and best practices relating to HTC. |
Blood and medical injection safety - Ensuring safe medical and waste management practices is important for HIV prevention, but it can be challenging in resource-limited settings where health workers are overburdened or not properly trained. USAID continues to make significant contributions in the area of medical injection safety in a number of countries. |
Technical Resources
The U.S. Agency for International Development works in partnership with the U.S. President's Emergency Plan for AIDS Relief.
December 2011
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