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What is HIV, and why research still matters
HIV attacks CD4 cells, the immune cells that coordinate the body's defenses. Without treatment, the virus slowly wears the immune system down until infections and certain cancers, like lymphoma, take hold. That stage is AIDS. With treatment, called antiretroviral therapy or ART, the virus is pushed to undetectable levels, the immune system recovers, and the person cannot transmit HIV sexually. Most people today take one pill a day, and long acting injections given every two months are also approved.
Prevention changed just as much. Pre exposure prophylaxis, PrEP, means taking medicine before possible exposure. It began as a daily pill, then an injection every two months, and in June 2025 the FDA approved lenacapavir (Yeztugo), a shot given twice a year. In its two large trials, 100 percent of women and 99.9 percent of men and gender diverse people who received it stayed HIV negative. Yet in 2023 more than 100 Americans were still diagnosed with HIV every day, and about 13 percent of people living with HIV are undiagnosed. There is still no cure and no vaccine, and both are active research fronts: studies now test antibodies that neutralize many HIV strains at once and drugs that shrink the hidden reservoir where the virus sleeps.
Types of HIV clinical trials
Treatment trials. Most test new long acting options: injections that last two, four, or six months, new once daily combinations, or switching from a daily pill to a shot. Because effective treatment already exists, new drugs are compared against approved regimens, never against no treatment, and success means keeping the virus undetectable.
Prevention and PrEP trials. These enroll people who are HIV negative and test new ways to stay that way: a once monthly PrEP pill, ultra long acting injections, and studies of how to make PrEP easier to start and stick with, especially in communities with the highest rates of new infections.
Cure research. HIV hides in resting cells that treatment cannot reach, which is why stopping medicine lets the virus return. Cure studies test broadly neutralizing antibodies, drugs that may shrink that reservoir, and treatment given in the very first weeks of infection. These are early, carefully monitored studies, and no cure exists yet.
Living with HIV studies. People with HIV now live long enough to face the same conditions as everyone else, sometimes earlier: heart disease, depression, bone loss. Studies test how to manage these alongside HIV, and how HIV related inflammation affects the body over decades.
Care delivery and behavioral studies. Self testing kits, home dried blood spot monitoring, telehealth, and programs that combine HIV care with substance use treatment. These often need no new medicine at all and address the gap between what works and who receives it.
What participating in an HIV trial involves
HIV trials are built around measurements you may already know from clinic visits: viral load (how much virus is in the blood) and CD4 count. Treatment trials keep everyone on an effective regimen, whether the study drug or an approved one. Prevention trials require regular HIV testing throughout, and cure studies involve closer monitoring and sometimes extra blood draws. Participants receive close follow up from the study team, and study related care is typically provided at no cost. Every trial also carries uncertainty: a study drug may work less well for you, may cause side effects, or the study may not answer its question. Privacy protections are strict, and all of this is explained during informed consent. You can leave a study at any time.
Who can participate in HIV clinical trials?
It depends on which side of HIV the study addresses. Treatment trials enroll people living with HIV and usually specify whether they want people who are already undetectable on treatment (for switch studies) or newly diagnosed and not yet treated. Many also ask about resistance test results. Prevention trials enroll HIV negative adults and adolescents at risk of exposure, and some focus on specific groups, such as Black and Latino men. Cure studies often want people diagnosed very recently, within weeks of infection, or people who have been undetectable for years. Care and behavioral studies frequently have the widest doors. Eligibility always varies by study.
The stages of HIV, and why they matter for trials
- Acute HIV. The first weeks after infection. Virus levels are very high and flu like symptoms are common. Some cure studies enroll only in this window, because treating this early keeps the hidden reservoir small.
- Chronic HIV. The long stage that follows, which can last decades. On treatment, the virus stays undetectable and the immune system stays healthy. Most treatment and switch studies enroll here.
- AIDS. Diagnosed when the CD4 count drops below 200 or an opportunistic infection appears. Rare in people on treatment. Some studies focus on treating and preventing these infections.
Study titles usually say "treatment naive," "virologically suppressed," or "acute infection" up front. Your most recent viral load and CD4 count, and how long you have been on treatment, tell you which studies fit.
Do HIV trial participants get paid?
Some studies offer compensation for time and travel, and study related care is typically provided at no cost to participants. Compensation varies by trial and is always described during the informed consent process before you agree to anything.
Curious whether clinical trials pay participants? Here's how compensation actually works.
How to enroll in an HIV clinical trial
Enrolling in an HIV study through our platform takes about 5 minutes. Here is how it works:
Identify your trial. Use the search bar or filters. HIV study titles are unusually clear: "PrEP" means prevention for HIV negative people, "virologically suppressed" means a switch study for people on treatment, and "cure" or "reservoir" means early stage research.
Select your preferred location. Enter your city or state in the filter on the left. Many HIV studies run at community clinics as well as academic centers, and some offer home visits or self testing, so check the study details.
Explore study details. Click "Learn More" for goals, procedures, and eligibility, including which current medicines are allowed, how often HIV or viral load testing happens, and whether injections or infusions are involved.
Complete the health profile. Click "Get started" to begin the 5-step application. Have three things ready: your HIV status and, if positive, your latest viral load and CD4 count; your current HIV medicine or PrEP, if any; and how long you have been on it. Those answers decide eligibility for most HIV studies. Your information is protected, and study teams are experienced in confidentiality.
Submit the application. A clinical trial coordinator reviews it and contacts you about whether you may qualify. Nothing is decided until you have gone through informed consent, and participation is voluntary at every step.