More than 1.1 million people are living with HIV in the United States, and more than 56,000 Americans become infected with HIV each year.1,2 Notwithstanding our nation's significant achievements in caring for people with HIV and the development of effective therapies, our ability to address the domestic epidemic depends on sustaining and expanding successful prevention strategies.
In July 2010, the Obama Administration released a National HIV/AIDS Strategy for the United States, which represents an effort to refocus national attention on ending the domestic HIV epidemic.3,4 The strategy is structured around 3 key goals and is intended to identify a small number of action steps to focus and align efforts across federal, state, local, and tribal levels (Table 1). Although the nation initially succeeded in reducing new HIV infections from 130,000 per year in the 1980s to 56,000 in the 1990s, overall HIV incidence in the United States has remained stable for more than a decade and continues to increase among men who have sex with men. while remaining stable or decreasing in other populations.1,5
The National HIV/AIDS Strategy sets a goal of reducing annual incidence by 25% by 20156 and recently published mathematical models confirm that this goal is achievable.7 To achieve this result, we must refocus prevention efforts on those communities at greatest risk. The nation must also adopt a more strategic and coordinated approach that utilizes a combination of effective HIV prevention interventions and stimulates innovation to develop additional effective scalable tools.
IMPROVING OUR PROGRAMMATIC RESPONSE TO REDUCE HIV INCIDENCE
Analogous to antiretroviral therapy (ART), which is highly effective when multiple medications are combined, effective prevention should involve multiple interventions to reduce risk behavior, reduce opportunities for transmission, and lower biological susceptibility of transmitting or acquiring infection. Despite the availability of evidence-based behavioral and biomedical tools that reduce HIV transmission or HIV risk (Table 2), the challenge for federal agencies and state and local partners responsible for delivering prevention services is understanding which combinations of prevention interventions will produce the most robust results in specific high-risk communities.
There is significant potential to reduce HIV transmission by scaling up prevention interventions targeting people who are diagnosed with HIV. Although studies show significant reductions in the HIV transmission rate when people with HIV are tested and learn their status, some HIV-infected individuals continue to engage in high-risk behaviors with partners who are HIV negative or of unknown status.7 For these HIV-infected individuals, it is important to provide a tailored approach that promotes physical, emotional, and sexual health.
In addition to promoting safer behaviors among people diagnosed with HIV, providing access to and improving the continuity of their care is critical. It is clear that ART both provides clinical benefits for people living with HIV and reduces the risk of transmission.8-10 Recent studies in Denmark, San Francisco, California, and British Columbia, Canada, have found encouraging reductions in HIV incidence associated with the uptake of ART by the majority of known positives.11-13 However, an estimated 30% of people living with HIV in the United States who are clinically eligible for ART are not receiving medical care and an additional 15% receiving medical care are not receiving ART.14 Individual clinical outcomes and population-level outcomes can be improved by increasing rates of ART usage when it is clinically indicated, as well as ART adherence. Although the decision to start ART is a personal one that every individual with HIV should discuss with his or her clinician, all HIV-infected persons in the United States should have access to uninterrupted health care that is coordinated and of high quality.
There is also an opportunity to improve our programmatic response to identifying individuals with unrecognized HIV infection. Approximately half of new sexually acquired HIV infections in the United States are transmitted by 21% of HIV-infected people who are unaware of their HIV status.2,15 Although guidelines for HIV testing in clinical settings have been in place since 2006, these recommendations have not been widely implemented.16 Routine HIV screening among targeted communities in reproductive health and sexually transmitted disease clinics, in emergency departments, in addiction treatment programs, and among partners of HIV-diagnosed individuals may reduce missed opportunities to identify and treat those with HIV. It is also important to concentrate testing resources in communities where testing is most likely to identify new, as well as chronic unrecognized infections. Expanded HIV testing efforts targeted among groups at highest risk for HIV infection in the District of Columbia was associated with a reduction in new AIDS diagnoses.17 Achieving similar outcomes nationally will require increasing provider awareness of HIV testing guidelines and addressing reimbursement disincentives for HIV testing services.
FUTURE RESEARCH TO REDUCE HIV INCIDENCE
Additional research is also necessary to help improve the nation's response to the domestic HIV epidemic. The last 2 years have been marked by significant advances in HIV prevention, particularly in microbicide and vaccine research.18-20 However, we must support further research to boost the effectiveness of promising microbicide and vaccine candidates and bring newer candidates through Phase II and III trials. Should existing research studies investigating the effectiveness of preexposure prophylaxis (PrEP) yield positive results,21 operational research must address how PrEP can best be integrated into comprehensive HIV prevention services for populations at greatest risk for HIV infection, and the provision of PrEP given existing resource constraints. We must also evaluate the degree to which behavioral disinhibition or inconsistent adherence to medications or specific regimens may undercut potential gains from these new prevention technologies.
Research must also continue to test new, more effective, and less costly HIV therapies and drug regimens that can reduce infectiousness with fewer side effects and clinical complications associated with long-term use among people living with HIV. These therapies, however, are effective only if individuals are diagnosed and successfully access care. Additional research is necessary to identify best practices to reach undiagnosed HIV-infected individuals, to link them to care, and, when clinically indicated, to provide medications. We must also develop and deploy better methods for diagnosing acute HIV infection.
Additional behavioral research and rigorous evaluation is needed to minimize decay of behavioral intervention effects and to provide more viable adaptations of effective behavioral interventions in clinic-based and community-based settings. HIV prevention efforts must also continue to move beyond addressing individual HIV risk behavior. Individuals in some disproportionately affected communities-particularly black gay men and black women-remain at greater risk for HIV infection, despite engaging in comparable or less risk than individuals in other communities.22,23 Because individual-level risk reduction interventions alone will not meaningfully reduce HIV incidence in some disproportionately affected communities, there must be an improved understanding of network, social, and structural factors that place individuals in specific communities at elevated risk for HIV infection.24,25
Thirty years into the HIV epidemic in the United States, it is unrealistic to expect that the National HIV/AIDS Strategy or our recommendations for reducing new infections would be composed entirely of new approaches to prevention. However, the innovation of the national strategy lies in its commitment to building on an evolving evidence base of what works, in identifying common national goals toward which federal, state, local, and tribal governmental partners and community partners can align their efforts, and in a renewed commitment to collaboration and coordination.
The authors would like to thank the members of the Federal Interagency Working Group for their contributions to the process of creating the National HIV/AIDS Strategy. We also thank Drs. Gary Marks and Gregory Folkers, as well as Ms. Wendy Wertheimer for their comments during the drafting of the manuscript. Last, we are grateful to the many individuals affected by or infected with HIV across the country who shared their stories, convened meetings, and provided recommendations that shaped the development of the National HIV/AIDS Strategy.
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