HIV Prevention

Preventing new HIV transmissions is a key step toward ending the HIV pandemic as we know it. NIAID-supported researchers have worked since the early days of AIDS in the 1980s to identify prevention tools to keep people healthy. Today, numerous prevention methods are available for use in combination or on their own, and scientists continue to work to develop and improve cutting-edge tools and techniques that can work to prevent HIV in diverse populations around the world.

Pre-exposure Prophylaxis (PrEP)

Pre-exposure prophylaxis, or PrEP, is a biomedical HIV prevention tool recommended for use worldwide to help protect people vulnerable to HIV. NIAID played an instrumental role in establishing the efficacy of PrEP and currently supports research to develop longer-acting forms of this prevention strategy. Read more about PrEP.

HIV Undetectable=Untransmittable (U=U), or Treatment as Prevention

Research has proven that treatment for HIV not only preserves the health of the individual, but also prevents sexual transmission of the virus to others. Read more about U=U.


NIAID supports research to develop a microbicide, a product that could be inserted into the vagina or rectum to safely block sexual transmission of HIV. Since women and girls are at particularly high risk for HIV/AIDS in many parts of the world, it is especially important to have an effective, desirable vaginal microbicide as an HIV prevention tool that women can control. Read more about microbicides.

Prevention of Perinatal Transmission

Perinatal HIV transmission—HIV transmission from mother to child during pregnancy, labor and delivery, or breastfeeding—accounts for most childhood HIV cases worldwide. NIAID research paved the way for development of approaches used to prevent perinatal transmission around the globe, and current work focuses on optimizing prevention strategies. Read more about prevention of perinatal transmission.

Passive Antibody Transfer

Passive antibody transfer is an experimental prevention technique that involves giving anti-HIV antibodies directly to an HIV-negative person by injections or intravenous infusions to protect them from HIV acquisition. NIAID supports research to test this strategy and to evaluate and improve antibodies that could be used for this purpose. Read more about passive antibody transfer.

Voluntary Medical Male Circumcision

Voluntary medical male circumcision protects against HIV by safely removing the foreskin, which is susceptible to infection, from the penis. Male circumcision significantly reduces the risk of sexually transmitting HIV from a woman living with HIV to a man and is recommended by the World Health Organization. NIAID-funded research played a major role in the discovery that male circumcision is an effective HIV prevention strategy. Read more about voluntary medical male circumcision.

Harm Reduction

Drug use and related behaviors, such as the exchange of sex for drugs or money, are linked to an increased risk of HIV acquisition. NIAID and other NIH institutes work to develop and optimize harm reduction interventions that decrease the risk of drug use-associated and sexual transmission of HIV among injecting and non-injecting drug users. Read more about harm reduction.

Condom Use

Consistent and correct condom use was one of the earliest recommendations for preventing HIV at the start of the pandemic outbreak in the early 1980s. It remains an essential tool in preventing the transmission of not only HIV, but also other sexually transmitted infections like gonorrhea and chlamydia. Latex condoms offer an impermeable barrier, preventing the bodily fluids that contain active HIV from entering a partner during sex. Read more about condom use.

Developing an HIV Vaccine

Development of an even partially effective HIV vaccine would accelerate progress toward an end to the global HIV pandemic. NIAID oversees a robust research program to develop and evaluate HIV vaccine candidates. HIV poses unique challenges to vaccine researchers because of the complicated interactions between the virus and the human immune system, but one large clinical trial has demonstrated a moderate degree of success. In 2009, a candidate vaccine regimen studied in more than 16,000 people in Thailand was the first to show protection, albeit modest, against HIV. NIAID-supported researchers are working to build on this modest success and continuing to explore multiple avenues toward an HIV vaccine. Read more about HIV vaccine development.

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