There is scientific evidence that a safe and effective HIV vaccine is possible. In 2009, a clinical trial in Thailand involving 16,000 people demonstrated for the first time that a vaccine could safely prevent HIV infection in a modest proportion of study participants. Many of the best minds in HIV vaccine science are examining blood samples and data from the Thai trial to learn how the vaccine candidate prevented HIV infections and to consider how it could be modified to be more effective.
To speed the pace at which promising HIV vaccine candidates become viable for evaluation in large clinical trials, NIAID is exploring the use of innovative or adaptive clinical trial designs that let scientists quickly modify ongoing trials in response to data acquired during the study. Such flexibility in trial design will allow the research community to maximize efficiencies in studying vaccine candidates.
Clinical trials of HIV vaccines depend on the participation of thousands of volunteers as well as community educators, health care workers and scientists. I am extremely grateful to the many people who devote their time and energy to these essential clinical studies.
Every HIV vaccine candidate is created in the laboratory. Some NIAID-supported laboratory scientists are charting a new course by designing HIV vaccine candidates based on knowledge of the protein structure of the surface spikes that HIV uses to attach to and infect human cells. These spikes have sites that are vulnerable to powerful antibodies, which block laboratory infection of human cells by more than 90 percent of tested HIV strains from around the globe. Now the scientists are mapping a strategy to create a vaccine that can stimulate a healthy person to make such broadly neutralizing antibodies.
To guide HIV vaccine design, other NIAID-supported scientists are building on evidence that in most individuals, only a small number of HIV particles — often just one — are responsible for establishing a sexually transmitted HIV infection. These researchers are identifying the unique qualities of these infection-causing forms of the virus to help other scientists design vaccines that target the specific HIV variants that penetrate the body’s defenses.
No matter how effective a preventive HIV vaccine is, however, we will need to evaluate and administer it in combination with other biomedical and behavioral HIV prevention tools. No single HIV prevention strategy will control and ultimately end the HIV/AIDS pandemic. That is why it is important for NIAID to continue supporting promising research on vaginal and rectal microbicides, pre-exposure prophylaxis (PrEP) and expanded HIV testing with linkage to care. That is also why public health workers will continue to advocate and implement scientifically proven HIV prevention strategies such as condom use, medically supervised adult male circumcision, harm-reduction strategies for injection drug users and the prevention of mother-to-child transmission of HIV.
On this extraordinarily challenging journey to develop a preventive HIV vaccine, taking a moment today to reflect on our progress gives us all renewed hope that our goal is achievable.
NIAID conducts and supports research — at NIH, throughout the United States, and worldwide — to study the causes of infectious and immune-mediated diseases, and to develop better means of preventing, diagnosing and treating these illnesses.