Traditionally, HIV prevention methods have included the use of condoms, clean needles, and behavior change. While those methods are effective, scientists are looking for medical strategies to prevent the spread of HIV. Experts believe that there will not be a “one size fits all” prevention strategy and the NIH has created a prevention “tool box” that includes both traditional and newer prevention methods. Communities across the U.S. will be able to pick and choose from this tool box and use the prevention method(s) that work best for them.
AIDS Project Los Angeles (APLA), primarily its Treatment Education Program and Prevention Programs, has years of experience educating the community about biomedical prevention. APLA has greatly benefitted from the support of the National Institute of Allergy and Infectious Diseases (NIAID). NIAID is a recognized pioneer in the study of HIV/AIDS and has helped improve standards of care of HIV-infected people in the United States and abroad. APLA has been a National HIV Vaccine Research and Education Initiative partner and is currently a national partner with its Be The Generation Bridge grant that helps us promote biomedical prevention awareness and education.
Below are five biomedical prevention strategies from the toolbox that are currently being used. The short description provides basic information about each strategy, and more detailed information is available by clicking the link that follows and downloading the PDF.
A vaccine improves immunity to a particular disease. Vaccines are designed to stimulate the body's own immune system to recognize a virus or bacteria as an invader, destroy it, and "remember" it so that the immune system can more easily recognize and destroy any of these invaders that it later encounters. In other words, vaccines trick your immune system to teach your body important lessons about how to defeat the invaders. Researchers have been working on a preventative vaccine for some time. There have been several breakthroughs in the last few years, but they have not yet developed a vaccine that works for at least 80% of the study participants who have received the vaccine. This is one reason why vaccine research is so important. HIV vaccines DO NOT contain live virus and a person cannot get HIV from an HIV vaccine.
What is an AIDS vaccine?
An AIDS vaccine is an experimental strategy that aims to teach the body's immune system how to fight HIV to reduce the risk of infection or to reduce viral load in those who get the vaccine and go on to become infected. All of the candidates being studied are experimental; there are no effective AIDS vaccines available today. None of the vaccines being tested can cause HIV.
Why are we looking at AIDS vaccines?
Vaccines are one of the world's most effective public health tools. Effective vaccines against polio, measles, mumps, rubella and other diseases have significantly reduced rates of these illnesses in many parts of the world. Today, many scientists, clinical trial teams and communities are working together on the search for an AIDS vaccine.
AIDS vaccine scientists are developing candidates that aim to block HIV infection in HIV-negative people, as well as candidates that aim to reduce viral load in people who receive the vaccine while HIV-negative and go on to become infected. Viral load is linked to disease progression, so a vaccine that reduced viral load could result in improved health and delayed time to initiation of antiretroviral treatment. Scientists are also developing therapeutic vaccines which would build immune strength in HIV-positive people. This fact sheet concentrates on prophylactic vaccines in development for HIV-negative people.
What is in the pipeline for AIDS vaccines of the future?
There are a range of candidates in early stages of development, and a wide range of basic scientific work (work not focused on product development) ongoing in the AIDS vaccine field.
Since prophylaxis means disease prevention, Pre-Exposure Prophylaxis, or PrEP, is a strategy that involves use of antiretroviral medications (ARVs) in HIV-negative individuals before they become exposed to the virus to reduce the risk of HIV infection via sexual exposure or injection drug use. Currently, the anti-HIV drug known as Truvada has been approved by the FDA for use as PrEP.
What medicine is currently being used as PrEP?
All of the current effectiveness and follow-on trials are testing tenofovir-based regimens—using either TDF/FTC (an antiretroviral containing tenofovir (TDF) and emtricitabine (FTC) that is sold under the brand name Truvada) or TDF (an antiretroviral pill marketed under the brand name Viread). Based on the data that have been collected to date the US Food and Drug Administration (FDA) announced its approval of daily oral TDF/FTC for PrEP. This is the first ARV to be approved for HIV prevention in HIV-negative adults.
What is happening now?
Regulatory and guidance activities
On July 16, the US FDA announced its approval of Gilead Science Inc.’s application for approval of daily oral TDF/FTC as PrEP. The US CDC is developing US Public Health Service (PHS) guidelines for the use of TDF/FTC as PrEP, which are expected late 2012/early 2013.
Much more needs to be learned about the safety and effectiveness of PrEP in the real world. Demonstration projects are designed to gather information on safety, efficacy and program design for new interventions. They help guide subsequent larger-scale introduction. Such projects are planned or underway for the US, Kenya, Nigeria and Uganda. In Los Angeles County, The County of Los Angeles, Department of Public Health, in partnership with UCLA, APLA, The LA Gay & Lesbian Center, and OASIS Clinic will soon be providing PrEP free of charge to people who are at risk for HIV infection, including men who have sex with men, transgendered persons, and negative partners in a sero-discordant couple or sexual relationship. This is a demonstration project study that will enroll 700 people to receive PrEP, testing and counseling over several years. The clinic sites are The L.A. Gay & Lesbian Center (Hollywood area): 1625 North Schrader Boulevard, Los Angeles, CA 90028, phone: 323.860.5880; and the OASIS Clinic (near Downtown/Compton): 1807 East 120th Street, Los Angeles, CA 90059, phone: 310.668.5131.
For a PDF of a Pre-Exposure Prophylaxis fact sheet, please click here.
Since prophylaxis means disease prevention, Post-Exposure Prophylaxis, or PEP, is a strategy that involves taking anti-HIV drugs as soon as possible after you may have been exposed to HIV to try to reduce the chance of becoming HIV-positive. To be effective, PEP must begin within 72 hours of exposure, before the virus has time to rapidly replicate in your body. Several HIV medications are indicated for use in PEP and are taken for a period of 28 days to prevent a new HIV infection.
What are the different types of Post-Exposure Prophylaxis?
PEP involves taking anti-HIV drugs as soon as possible after you may have been exposed to HIV to try to reduce the chance of becoming HIV-positive. There are two types of PEP: (1) occupational PEP, (sometimes called "oPEP"), and (2) non-occupational PEP, (sometimes called “nPEP”). Workplace exposure (oPEP) is when someone working in a health-care setting is potentially exposed to material infected with HIV. nPEP is when someone is potentially exposed to HIV outside the workplace (e.g., condom breakage, sexual assault, etc.)
To be effective, PEP must begin within 72 hours of exposure, before the virus has time to rapidly replicate in your body. PEP consists of 2-3 antiretroviral medications and should be taken for 28 days. Your doctor will determine what treatment is right for you based on how you were exposed to HIV. The medications have serious side effects that can make it difficult to finish the program. PEP is not 100 percent effective; it does not guarantee that someone exposed to HIV will not become infected with HIV.
Who Needs PEP?
PEP is usually used for anyone who may have been exposed to HIV. Healthcare workers have the greatest risk. They can be exposed to HIV by:
The risk of HIV transmission in these ways is extremely low—less than one percent for all exposures. PEP can also be used to treat people who may have been exposed to HIV by accident (e.g., condom breakage) or sexual assault.
When Should I Take PEP if I’ve Been Exposed?
PEP is most effective if you take it within 72 hours of possible HIV exposure. The longer you wait to start PEP, the greater the risk of becoming HIV-positive.
Your healthcare provider will consider whether PEP is right for you based on how you might have been exposed and whether you know for sure that the individual who might have exposed you is HIV-positive. You may be asked to return for more HIV testing at four to six weeks, three months, and six months to determine your HIV status.
Where Can I Get PEP?
Some of the places you can go to seek treatment include your doctor’s office, emergency rooms, urgent care clinics, or a local HIV clinic. In Los Angeles County, The County of Los Angeles, Department of Public Health funds two clinics to provide PEP free of charge to those people at risk for HIV infection who do not have insurance to pay for the medication. Testing and counseling are also provided at these clinics. The clinic sites are The L.A. Gay & Lesbian Center (Hollywood area): 1625 North Schrader Boulevard, Los Angeles, CA 90028, phone: 323.860.5880; and the OASIS Clinic (near Downtown/Compton): 1807 East 120th Street, Los Angeles, CA 90059, phone: 310.668.5131.
Microbicides are currently being studied in research in people at risk for HIV infection. The hope is that microbicides will be easy to use, when condoms are not always a reality, and will kill all HIV before it can infect the person who uses them. Microbicides are currently being studied in different forms: foam, gel, cream or slow-release vaginal ring, all of which contain an anti-HIV drug. The foam, gel, cream, ring or suppository gets inserted into the vagina and/or rectum to reduce the risk of HIV transmission during sex. Advances have been made in both vaginal and anal microbicides, but none have been approved by the Food & Drug Administration (FDA).
The idea for a microbicide-like product was first proposed more than 20 years ago by reproductive health specialists and advocates who recognized the need for female-controlled HIV prevention methods. One of the first products considered was the spermicide nonoxynol-9 because researchers believed it might also be effective against HIV. Unfortunately, research showed it was neither safe nor effective against HIV. Other trials of different so-called first generation microbicides also proved unsuccessful. These included products intended to strengthen natural defenses in the vagina or create a barrier to protect target cells in the vagina.
Researchers are now evaluating HIV prevention products that are based on antiretroviral (ARV) drugs, including ARVs commonly used in HIV treatment. The most studied ARV-based microbicide is tenofovir gel, which was found safe and effective in reducing the risk of HIV in women who used it before and after vaginal sex in a study called CAPRISA 004. Although an interim data review of another study called VOICE found tenofovir gel was safe, it was not effective among the women in the study who were asked to use the gel every day. It won’t be possible to understand why tenofovir gel was not effective in VOICE until after the study is completed and results are available. In the meantime, tenofovir gel continues to be evaluated in FACTS 001, a Phase III trial testing the same regimen of tenofovir gel used in CAPRISA 004.
What will it take to discover a Safe and Effective Microbicide?
Testing many products is necessary before finding even one microbicide that will be safe and effective against HIV and also easy and acceptable to use. Different products work in different ways, and researchers do not yet know which ones will work best. A handful of candidate microbicides are in various stages of clinical study; additional compounds are in early stages of development.
Drug development is a long and arduous process, often taking up to 20 years before just one product is approved for general use. Thousands of potential compounds may be considered during drug discovery but only the most promising products are subjected to rigorous laboratory and animal studies, and fewer still make it to trials with people. Clinical trials are carried out in several phases under the oversight of regulatory and research authorities and according to strict ethical and scientific guidelines. Phase I trials are designed to evaluate safety in a small number of people who are exposed to study products for short periods, say, one to two weeks. If results of a Phase I study suggest the product is safe, investigation progresses to a Phase II trial, in which researchers continue to track safety over more extended periods of time. Phase IIb and III trials are performed to determine how effective a product may be and are conducted with large numbers of participants, typically at multiple clinical centers. These trials are usually designed to compare a product with an inactive product (a placebo) or another active product. Data from Phase IIb and Phase III trials are often used by regulatory agencies to determine if a particular product should be approved for widespread use.
For a PDF of a microbicides fact sheet, please click here.
Treatment as prevention is an effective prevention strategy because the HIV medications today are potent and durable enough to lower HIV viral loads to undetectable levels in the blood and keep it there. That is why it is important to take the HIV medication as prescribed. Treatment as prevention works as a dual-strategy since we know that treatment leads to undetectable virus in the person living with HIV. By taking the HIV treatment as prescribed, this shuts down production of HIV and allows the immune system to rebuild itself and make healthy new T-cells. This improves the health of the person living with HIV. Also, we know from studies that people who maintain undetectable HIV viral loads are much less likely to transmit the virus during sexual encounters. This helps to decrease the number of new HIV infections. The more people living with HIV on effective treatment, the less HIV that is out there in the community.
What is meant by ARV treatment as prevention?
“Treatment as prevention” is a term describing the use of antiretroviral drugs that are used to reduce the risk of passing HIV to others. The strategy would function as a secondary benefit of antiretroviral treatment (ART) after its primary purpose of improving an individual’s health. The rationale for this approach is that ARVs reduce viral load. Higher viral loads have been linked to increased risk of passing HIV to sexual partners. Treatment as prevention is an emerging area and there are different terms and phrases used to describe different strategies using this approach. These include “test and treat” and “testing and linkage to care plus (TLC-plus)”.
What are the data on treatment as prevention?
There is one ongoing efficacy trial, called HPTN 052, which enrolled 1,763 serodiscordant couples (one HIV-positive and one HIV-negative partner) to look at ARV treatment as prevention in a number of countries. It asks whether initiating treatment in the HIV-positive partner can help reduce the risk of sexual transmission of HIV to the HIV-negative partner and whether the effect is a durable one. It is also looking at the possible benefits of early treatment versus those who delay initiating therapy until it is clinically indicated. All participants in the trial receive a basic prevention package including treatment for sexually transmitted infections, condoms and behavior change counseling.
In May 2011, at a scheduled review of interim data, the trial’s independent Data Safety and Monitoring Board (DSMB) found clear evidence that providing immediate ART to the HIV-positive partner reduced the risk of transmitting HIV to their HIV-negative partner by 96 percent. The trial team also noted that those on treatment had a significantly reduced risk of extra-pulmonary TB, an important individual benefit. Based on this indication of benefit, the DSMB recommended that the trial halt randomization and that immediate treatment be offered to all HIV-positive partners. This process is ongoing and all couples will continue to be followed until the protocol-defined end of the trial in 2015.
For a PDF of a Treatment as Prevention fact sheet, please click here.
Where can I get more information about HIV Biomedical Research?
The following websites are excellent resources:
Be The Generation
HIV Vaccine Trials Network
HIV Prevention Trials Network
Microbicide Trial Network
The International HIV Vaccine Advocacy Initiative
The AIDS Vaccine Advocacy Coalition
Hope Takes Action
AIDS Research Alliance
UCLA CARE Center
If you have any questions regarding the content of this page or would like to know more about biomedical prevention, please visit the links in the fact sheets or contact APLA’s Treatment Education Program at 213.201.1616.
This website was made possible in part by a grant from the BTG Bridge Project, a collaboration between HIV Prevention Trials Network (HPTN)/FHI360 and the Legacy Project at the Office of HIV/AIDS Network Coordination (HANC). For more information, visit bethegeneration.nih.gov.