Reduce the Incidence of HIV

Research has led to groundbreaking discoveries in HIV prevention that have been adopted globally. NIH-sponsored studies have developed treatments to prevent HIV, including pre-exposure prophylaxis (PrEP), which studies have shown reduces the risk of transmission during sex by as much as 92 percent, and post-exposure prophylaxis (PEP), which can protect people who have had a one-time exposure to HIV.

Research also has found that antiretroviral therapy—medications to manage HIV—can prevent transmission of HIV to uninfected sexual partners when taken appropriately. This is referred to as “treatment as prevention.”

Preventing new infections will be critical to achieving an end to the HIV pandemic. Additional biomedical research, development of new tools, and addressing behavioral and social factors all will be needed to reduce the incidence of new cases of HIV. Historically, vaccines have been integral to preventing the spread of many infectious diseases. The development of a safe and effective HIV vaccine remains a key strategy for ending the pandemic.

Advances in HIV Vaccine Development

Research toward developing an HIV vaccine remains a high priority for the NIH. Major clinical trials are testing the effectiveness of HIV vaccines:

• The HVTN 702 study - based on the landmark trial conducted in Thailand of RV144, which was the first vaccine to provide some protection against HIV, was discontinued in early 2020. Researchers had developed the HVTN 702 to provide protection against the predominant HIV subtype in southern Africa. NIH and partners stopped the vaccinations after an independent data and safety monitoring board (DSMB) found that the regimen did not prevent HIV. To learn more see, Experimental HIV Vaccine Regimen Ineffective in Preventing HIV.
• The HVTN 705 study—also known as “Imbokodo,” the Zulu word for rock—is testing “mosaic” immunogens—vaccine components that are designed to trigger immune responses against a wide variety of HIV strains. HVTN 705 may provide the basis for a global HIV vaccine. Results are expected in 2021.

Advances in Nonvaccine Prevention Methods

In addition to its research into an HIV vaccine, the NIH continues to support basic, preclinical, translational, and clinical studies to advance research on nonvaccine therapies.

The Antibody-Mediated Protection (AMP) study (HVTN 704/HPTN 085) is testing a new alternative to vaccines for HIV prevention. Preclinical tests have demonstrated that certain broadly neutralizing antibodies (bNAbs) can block infection by several strains of HIV. AMP is testing whether the bNAb VRC01 can neutralize HIV in humans when it is given directly (by infusion). The trial will determine an appropriate dose of the antibody and how long the protection lasts.

Other studies are underway to evaluate the long-term benefits of new prevention strategies—including microbicides, intravaginal rings, and other methods—to protect women and men from acquiring HIV through sex. These methods will offer particular advantages for women who may not have other options for protection.

The Role of Behavioral and Social Sciences

Although effective HIV prevention options currently exist, significant disparities or inequalities in access to care, treatment adherence, and health outcomes limit their use. Disparities persist by race, ethnicity, sex and gender, age, and socioeconomic status, among others. Social determinants of health, such as poverty, unequal access to health care, stigma, racism, and lack of education contribute to health disparities.

Behavioral and social sciences research (BSSR) addresses the behavioral and social factors that are barriers to HIV prevention and also helps identify factors that can facilitate HIV prevention. The NIH supports in BSSR to better understand disparities and the behavioral and social factors that influence HIV transmission and prevention. For example, factors such as mental health status or substance use, may influence the adoption of prevention strategies.

Advances have been made in understanding and addressing the social contexts and behavioral factors that impact biomedical, behavioral, and combination HIV prevention interventions. Examples include facilitating uptake of testing and counseling, developing technology-based interventions that increase viral suppression, reducing HIV/AIDS-related stigma, and addressing other sociobehavioral and structural barriers to HIV prevention and reducing HIV incidence.

Through ongoing research, the NIH will continue to build on successes and develop innovative strategies to prevent new cases of HIV, reduce HIV transmission, advance treatment adherence, and improve the health outcomes of people with HIV.