About HIV Vaccines

Dr. Steven Santiago and Wolfgang Tillero at Care Resource, Miami

Our goal is to find a preventive HIV vaccine that will protect people against HIV, the virus that causes AIDS. The experimental HIV vaccines should produce either antibodies or cytotoxic T cells (CTLs) to fight infection. HIV vaccines currently being tested in humans are made from man-made materials that CANNOT cause HIV infection.

Possible Outcomes

Scientists believe that an effective HIV vaccine, given before exposure to HIV, could have a number of possible outcomes. These include:

Preventing infection in most people
Preventing infection in some people
Preparing a person's immune system to block continued infection and eliminate the virus (vaccines against measles, mumps and polio work this way)
Delaying or preventing the onset of illness or AIDS

The long-term goal is to develop a vaccine that is 100 percent effective and protects everyone from infection. However, even if a vaccine only protects some people, it could still have a major impact on controlling the epidemic. A partially effective vaccine could decrease the number of people who get infected with HIV; those people, in turn, would not pass the virus on to others. Even when an HIV vaccine is developed, education and other prevention efforts will be needed so that people continue to practice safe behaviors.

Preventive versus Therapeutic HIV Vaccines

Preventive HIV vaccines are designed to protect HIV-negative people and to control the spread of HIV. They are not designed to cure AIDS.

Multiple HIV vaccines may be necessary to prevent infection or disease in the same way multiple drugs are needed to treat people already infected with HIV.

Researchers are also evaluating therapeutic vaccines to treat people with HIV infection or AIDS. While the same vaccine may be tested for both preventive and therapeutic effects, what works to prevent HIV infection may not necessarily work to treat people who are already infected with HIV.

Testing HIV Vaccines

Vaccine development requires several years of research in laboratories and animals before testing in humans can begin. A potential vaccine goes through three phases of testing in humans before the Food and Drug Administration (FDA) can consider licensing it for public use. The three phases of preventive HIV vaccine clinical trials are:

Phase I - involves a small number of healthy volunteers (HIV-negative) to test the safety and various doses of the vaccine; usually lasts 12 to 18 months.
Phase II - involves hundreds of volunteers (HIV-negative) to test the safety and immune responses of the vaccine; can last 2 to 4 years. The Step Study is Phase II trial.
Phase III - involves thousands of volunteers (HIV-negative) to test the safety and effectiveness of the vaccine; can last 3 to 4 years.

Throughout all phases of human testing, independent reviewers regularly monitor the study to ensure the safety of the volunteers.

For more information on HIV vaccines and the phases of testing, visit www.hvtn.org.


	About HIV Vaccines Our goal is to find a preventive HIV vaccine that will protect people against HIV, the virus that causes AIDS. The experimental HIV vaccines should produce either antibodies or cytotoxic T cells (CTLs) to fight infection. HIV vaccines currently being tested in humans are made from man-made materials that CANNOT cause HIV infection. Possible Outcomes Scientists believe that an effective HIV vaccine, given before exposure to HIV, could have a number of possible outcomes. These include: Preventing infection in most people Preventing infection in some people Preparing a person's immune system to block continued infection and eliminate the virus (vaccines against measles, mumps and polio work this way) Delaying or preventing the onset of illness or AIDS The long-term goal is to develop a vaccine that is 100 percent effective and protects everyone from infection. However, even if a vaccine only protects some people, it could still have a major impact on controlling the epidemic. A partially effective vaccine could decrease the number of people who get infected with HIV; those people, in turn, would not pass the virus on to others. Even when an HIV vaccine is developed, education and other prevention efforts will be needed so that people continue to practice safe behaviors. Preventive versus Therapeutic HIV Vaccines Preventive HIV vaccines are designed to protect HIV-negative people and to control the spread of HIV. They are not designed to cure AIDS. Multiple HIV vaccines may be necessary to prevent infection or disease in the same way multiple drugs are needed to treat people already infected with HIV. Researchers are also evaluating therapeutic vaccines to treat people with HIV infection or AIDS. While the same vaccine may be tested for both preventive and therapeutic effects, what works to prevent HIV infection may not necessarily work to treat people who are already infected with HIV. Testing HIV Vaccines Vaccine development requires several years of research in laboratories and animals before testing in humans can begin. A potential vaccine goes through three phases of testing in humans before the Food and Drug Administration (FDA) can consider licensing it for public use. The three phases of preventive HIV vaccine clinical trials are: Phase I - involves a small number of healthy volunteers (HIV-negative) to test the safety and various doses of the vaccine; usually lasts 12 to 18 months. Phase II - involves hundreds of volunteers (HIV-negative) to test the safety and immune responses of the vaccine; can last 2 to 4 years. The Step Study is Phase II trial. Phase III - involves thousands of volunteers (HIV-negative) to test the safety and effectiveness of the vaccine; can last 3 to 4 years. Throughout all phases of human testing, independent reviewers regularly monitor the study to ensure the safety of the volunteers. For more information on HIV vaccines and the phases of testing, visit www.hvtn.org.