Our Research

40 years of HIV related research

Scientific research has been at the heart of every breakthrough we’ve made in the fight against HIV. Bridge HIV has been at the forefront of that research for four decades – continuing the long public health tradition of looking for preventive methods to stop new infections from occurring.

HIV affects everyone, but men and women of color and men who have sex with men are particularly heavily impacted. These same groups have also persevered and pioneered methods of preventing and living with HIV that have benefitted other communities globally.

As we search for innovative solutions to guide HIV prevention, we continue to conduct clinical trials of promising strategies to understand their effectiveness and safety across different populations at risk for HIV infection. These strategies include the search for an effective HIV vaccine, PrEP (Pre–Exposure Prophylaxis), rectal and vaginal microbicides, vaginal rings, HIV self-testing, and interventions to help achieve health equity.

Learn more about the individual research studies we’ve participated in over the last forty years below.

Visit us at to learn more about studies we are are currently enrolling.

The San Francisco City Clinic Cohort Study grew out of studies of hepatitis B infection in 6,704 men who have sex with men from 1978-1981. In collaboration with the Centers for Disease Control, we were part of the research team who contacted men from the original study to participate in the San Francisco City Clinic Cohort Study.

Because of long-term clinical data on both men who remained HIV uninfected as well as known dates of infection in men living with HIV, a number of insights were gained from this study. Some of these include identifying risk factors for HIV acquisition; time from HIV infection to disease progression; genetic and immunologic factors associated with disease progression; and recognizing new clinical outcomes associated with HIV. A group of people were identified who were HIV-infected but had limited disease progression without using anti-HIV medication. This group is also known as long-term non-progressors (LTNP). This study, the longest-ongoing of its kind, examined what immune responses and genetic factors may play a role in protecting their health, and to see if their immune responses could be mimicked in drugs or vaccines to benefit others.

We have a long history conducting and leading over 40 HIV vaccine research studies including more than 1,000 study participants in the San Francisco Bay Area. These HIV vaccine studies investigate the safety, immune response, and protection from HIV of different types of HIV vaccines. Because none of the vaccines use whole, live, killed, or weakened HIV it is not possible to get HIV from any of these HIV vaccines. Instead, the vaccines use man-made imitations of pieces of the virus to try and train the body’s immune system into creating a response to a threat that isn’t there.

These are just a selected few of the HIV vaccine studies we’ve conducted at Bridge HIV.

HVTN 117 andHVTN 118 (both in long-term follow-up) evaluates the safety, tolerability and immune response of two different vaccines, which could be the foundation for the first global HIV vaccine. These two early studies showed success in stimulating an immune response, and are being followed up with a larger study to test if it also works to prevent HIV infection.

HVTN 704/HPTN 085 (AMP Study) (Ongoing) tests a special antibody against HIV called VRC01. VRC01 is special because it’s a broadly neutralizing antibody, or “bnAb”, which has prevented many different strains of HIV from infecting cells in early laboratory studies. The AMP Study is testing whether this bnAb antibody can prevent HIV infection in humans. Antibody Mediated Prevention (AMP) is the idea of giving people antibodies that fight HIV to see if they will protect people from becoming infected. This study currently ongoing and we expect to have study results in the next couple years.

HVTN 505 (Completed follow-up in 2017) evaluates the safety and effectiveness of two different types of vaccines to examine whether a vaccine, which uses DNA and protein, can prevent new HIV infections. The study also examined whether this vaccine strategy reduces the level of HIV virus in a person’s system if they do become infected. This study enrolled 2,504 people worldwide. Although this vaccine study didn’t show protection from HIV infection, we are still learning how it trained the immune system which has been helpful to guide our future HIV vaccine development.

HVTN 502/Merck 023(Step Study) & HVTN 504 (Completed follow-up in 2009) investigates whether a vaccine that used a disabled common cold virus to deliver HIV information to the body’s immune system could effectively prevent HIV infection, or delay disease in someone who did become infected. This study was the third HIV vaccine efficacy trial ever conducted and enrolled 3,000 people worldwide. Vaccinations in the study were stopped because there was no evidence the vaccine was offering protection against HIV.

VAX004 (Vaxgen/AIDSVAX) (Completed follow-up in2003) was the world’s first efficacy study of an HIV vaccine and enrolled 5,400 people worldwide. The vaccine was not effective in preventing HIV infection but taught us important lessons that helped guide future HIV vaccine research.

The only HIV vaccine trial which showed protection from HIV infection was the RV144 trial among 16,000 participants in Thailand. This study showed 31% fewer HIV infections among people who received the HIV vaccine, compared with those who received a placebo (salt water) injection. Although this study was conducted outside of the US, Bridge HIV conducted an early phase trial (HVTN 203) of the vaccine regimen used in RV144, and is conducting a follow-up study (HVTN 120) to evaluate the safety and immune response of a modified version of this HIV vaccine with a new immune booster.

Project T evaluated the safety and tolerability of daily use of tenofovir, a commonly prescribed HIV medication, in HIV-uninfected men, with the ultimate goal of developing this drug for use as pre-exposure prophylaxis – taking a daily pill to prevent HIV infection. This was the first study of pre-exposure prophylaxis for men who have sex with men, and was conducted in San Francisco, Atlanta, and Boston.

The STRAND Study tested the measurement of PrEP drug levels in hair as a new way of monitoring adherence to PrEP (how often PrEP is taken). In this study, participants took different dosing regimens of PrEP (2, 4, or 7 times a week) using directly-observed dosing, and hair was collected and tested for PrEP drug levels. This study showed a strong relationship between frequency of dosing and tenofovir levels in hair. These results suggest that hair measures of adherence are a promising approach to monitoring PrEP use in real-world settings. This study also set benchmarks for how much drug was present in the blood and in hair, depending on the number of times per week that doses were taken, and in combination with the iPrEx study, showed that taking the PrEP drug (Truvada©) four times per week for men who have sex with men was almost as effective as daily dosing.

iPrEx was a landmark study in HIV prevention. It tested whether daily use of a medication called emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) or Truvada© could safely and effectively prevent HIV infection in men who have sex with men and transgender women. The results from the study showed that if taken daily Truvada© as PrEP (Pre-Exposure Prophylaxis) could reduce the risk of getting HIV from sex by more than 90%.  On July 16, 2012 the FDA approved Truvada© as the first drug approved to reduce the risk of HIV infection.

iPrEx OLE (open-label extension) was the continuation of the iPrEx study and designed to provide additional information about the safety of PrEP and the behavior of people taking PrEP over a longer term. The results showed that PrEP provides a high degree of protection against HIV infection, even for individuals who miss some daily doses. Additionally it showed there is a high interest in PrEP, longer-term evidence of safety and efficacy of Truvada© as PrEP, and no signs of increased risk behavior among PrEP users.

HPTN 069 was a study to learn more about the safety and acceptability of a drug called maraviroc. This study was an important next step in helping to determine if future research should be done to see if maraviroc-containing regimens taken orally can be used as PrEP.

HPTN 077 tested both a pill and a long-acting injectable (a shot) of an investigational HIV drug called cabotegravir to answer whether both forms of the drug are safe and well tolerated, for potential use as PrEP in the future. The study also aimed to help understand whether people are willing to receive these injections and how they feel about getting them. Researchers evaluated the use of this medicine for both the prevention and treatment of HIV infection while also looking at pharmacokinetics, which is how the body processes the drugs, and how long they last in the body after being taken.

HPTN 083 is the first large-scale clinical trial of a long-acting injectable drug with the potential to be used for HIV prevention. The study is examining whether a long-acting form of the anti-HIV drug cabotegravir injected once every 8 weeks can safely protect people from getting HIV infection at least as well as another anti-HIV medication combination taken as an oral tablet daily. The oral tablet, called Truvada©, consists of the two anti-HIV drugs – emtricitabine and tenofovir disoproxil fumarate (TDF/FTC).

The Stay Study is a multi-site, open-label HIV pre-exposure prophylaxis (PrEP) demonstration project for advancing PrEP delivery in the San Francisco Bay Area Transgender Community. The study provides access and support for taking PrEP, with the goal of helping the trans and gender non-conforming community stay HIV negative.

DOT DBS tested the measurement of PrEP drug levels in dried blood spots (DBS) as a way to monitor PrEP adherence. Participants were asked to take different dosing regimens using directly-observed dosing, and drug levels in DBS were measured. This study showed that drug levels in DBS were very useful in predicting frequency of PrEP use and can be a helpful tool for interpreting results from a variety of PrEP studies.

MTN 017 was the first Phase II trial of a rectal microbicide for HIV prevention. The study tested a reduced glycerin tenofovir gel as compared to oral Truvada© and sought to answer whether tenofovir gel is safe and acceptable as a rectal microbicide. The study also addressed how this product might be used in real life situations and was designed to provide the needed safety data to move forward with a large effectiveness study.

MTN 028 tested a vaginal ring containing 2 different HIV medications. The main purpose of this research study was to find out how two different dose combinations of study drugs are absorbed and processed by the body and to better understand the safety of the study drugs. Information from the study will be used to help develop vaginal rings in the future, including combination rings that could be used to prevent both pregnancy and HIV. Vaginal rings that slowly release HIV medication over weeks or months (like contraceptive rings) could be an effective alternative to oral PrEP or vaginal gels.

MTN 036/IPM 047 tests 3 vaginal rings containing 3 different doses of an anti-HIV medication called Dapivirine (DPV). The main purpose of this research study was to find out how the different dose combinations of study drug is absorbed and processed by the body, to better understand the safety of the study drug, and to determine how comfortable they are to wear. In addition, the study looked at how the study drug is absorbed and processed when a higher dose, extended use vaginal ring is used for 13 weeks compared to a ring used for 4-5 weeks.

MTN 038 – description coming soon
MTN 035 – description coming soon

mHealth (mobile health) is a general term to describe the use of mobile phones and other wireless technology in medical care. Using mobile devices to help support personal health or educate about preventive healthcare services is the most common application of mHealth.

Similar to our PrEP and vaccine studies, all of our mHealth studies have questions related to health equity and seek to enroll members from communities hardest hit by the HIV pandemic.

DOT Diary is a mobile app, which combines two HIV prevention strategies to assess the impact of the DOT Diary app on adherence to HIV pre-exposure prophylaxis (PrEP) for the prevention of HIV. The app reminds people when it is time to take their daily PrEP pill and uses motion-sensing technology to visually and automatically confirm the pill was swallowed. The app also includes a sex diary to help users track their sexual encounters. Users are able to visually see the days they took PrEP overlaid with days of sexual activity, allowing participants to see whether their sexual encounters were covered by PrEP.

The EPIC study tested a mobile health text-messaging intervention, PrEPmate, as a strategy to improve adherence to daily PrEP in young men who have sex with men aged 18-29. PrEPmate provided weekly check-ins regarding PrEP use, as well as daily reminders for pill-taking.

HOME combines access to HIV self-testing/STD self-collection kits with a set of online support tools for black and latino men who have sex with men (MSM). The study explores how home HIV testing/STD collection tests are used and whether online tools would help connect participants with HIV prevention services such as Pre-Exposure Prophylaxis (PrEP) if they test HIV negative or to HIV treatment and care services if they test HIV positive.

Lynx is a highly interactive mobile app to promote accurate risk perception, increase HIV and STD (sexually transmitted disease) testing, and linkage to PrEP among young men (ages 15-24) who have sex with men (YMSM). Key components of the app include: Sex Pro, a personalized HIV protection score; a sex diary to help users track their sexual activity; HIV/STI testing reminders; access to home HIV/STI testing kits; a geospatial-based locator of HIV/STI testing sites and PrEP clinics; PrEP information and videos; and online PrEP navigation.

PHASTT is a highly interactive mobile app to promote accurate risk perception, increase HIV and STD (sexually transmitted disease) testing, and linkage to PrEP among young Black men (ages 18-29) who have sex with men. Key components of the app include: Sex Pro, a personalized HIV protection score; a sex diary to help users track their sexual activity; HIV/STI testing reminders; access to home HIV/STI testing kits; a geospatial-based locator of HIV/STI testing sites and PrEP clinics; PrEP information and videos; and online PrEP navigation.

Quickie Survey seeks to learn about sexual health and HIV prevention strategies among HIV-uninfected transwomen and men who have sex with men in the Bay Area. Participants are asked to complete four short surveys about their sexual practices as well as their knowledge, preferences, and use of new HIV prevention methods such a PrEP over a 9-month period. These data will be used to evaluate how well people are accessing HIV prevention services and inform new ways to improve our HIV prevention efforts in the Bay Area.

Circuit Party Study explored why men attend circuit parties, what factors are associated with higher risk sexual practices in that environment, and awareness and/or use of PEP and PrEP.

Explore Study looked to see if participating in an intensive counseling program would help people protect themselves against HIV and other sexually transmitted diseases.

New Choices explored the emerging factors in gay men’s sexual behavior with an eye on creating appropriate prevention messages for the community.

Project Embrace/Brazos Abiertos looked at the reasons why African American and Latino people decide whether or not to participate in HIV vaccine research, and what we can do to increase their involvement.

Unity (HPTN 061) was a research study conducted by Bridge HIV as part of a larger, national study called The Brothers Project, or HPTN 061. It was the largest study ever conducted in the United States on how health, sexuality, and other life issues impact the risk for HIV/AIDS among black men and trans people.

JUMPSTART was the first vaccine preparedness study conducted from 1991-1993 in San Francisco, Denver, and Chicago, to learn about risk factors for HIV infection and to explore whether men who have sex with men would be willing to participate in future HIV vaccine studies.

VPS (Vaccine Preparedness Study) was a prospective cohort study conducted in 1995-1997 evaluating whether it was possible to rapidly recruit and retain large numbers of participants at risk for HIV infection for 18 months, and to learn about their interest in participating in future HIV vaccine and other prevention trials.

Vision was a substudy of the VAX004 (Vaxgen/AIDSVAX) study. It explored trial experiences, motivations, and decision-making processes of a subset of VAX004 study participants and another group of people who demographically and behaviorally matched the AIDSVAX cohort but received neither vaccine or placebo products.

ACE (HPTN 039) tested whether preventing genital herpes outbreaks with twice-daily acyclovir among HIV negative people would prevent them from getting HIV.

Men’s Health Survey – description coming soon
Project Mix – description coming soon

PUMA (Prevention Umbrella for MSM in the Americas) was a project pre-dating pre-exposure prophylaxis that focused on identifying those interventions likely to have the greatest impact on HIV prevention for MSM throughout North and South America. With sites based in San Francisco, New York, Lima, and Rio de Janeiro, PUMA investigators developed and evaluated a tool for calculating a sexual health promotion score, validated it in contemporary cohorts, and launched its use for determining eligibility in the HPTN 083 study and for encouraging PrEP uptake in the HOME study. PUMA investigators also modeled the impact of various interventions on HIV infections country-wide, and evaluated provider and user interest in home HIV self-testing.

Sex Pro (Sexual Promotion Score) is a calculation tool developed by Bridge HIV to help people better understand their sexual health and HIV risk. After answering a few questions about sexual activity and drug or alcohol use over the last three months, the responses are used to calculate the personalized Sex Pro Score, which ranges between 1 and 20. The higher the score, the higher protection against HIV.