Preventive trials Why develop a preventive vaccine against HIV?

The development of a preventive vaccine against HIV represents the best solution for controlling and eradicating the HIV pandemic

• Worldwide, over 37 million people are currently infected with HIV, and 1.7 million new cases are reported annually. Less than half of the people living with HIV have access to antiretroviral treatments.

• In France, there are 170,000 infected people—nearly 425,000 of whom are unaware of their status, and continue to spread the epidemic—and 6,200 new cases in 2008.

• Other preventive strategies exist (use of condoms, PrEP: pre-exposure prophylaxis with antiretrovirals); however, the medical/scientific community agrees that only a combination of these strategies with a preventive vaccine will make it possible to control the growth of the epidemic of HIV infection

What types of clinical trials on preventive vaccines against HIV are currently being conducted by the VRI?

The trials currently being developed by the VRI are phase I and II clinical trials.

Development of a vaccine requires, after testing in animals to ensure the absence of toxicity, the establishment of 3 successive phases

• Phase I. At this stage, trials are conducted with a limited number of subjects under strict medical supervision. The vaccine is tested over a short period. The objective is to evaluate its safety of use, its fate in the body, and potential adverse effects.
• Phase II. Trials are conducted on a larger number of subjects. These trials are usually comparative according to the international clinical trial standard settings: one of the two volunteer groups is given the vaccine whereas the other is given a placebo. They are aimed at obtaining data on safety of use for a larger number of subjects, and studying the immunogenicity (induction of an adaptive immune response) of the vaccine. Currently, these phase II trials generally involve testing vaccine combinations of several vaccine candidates.
• Phase III. Trials are conducted on large volunteer populations, to allow measurement of the efficacy of the vaccine, i.e. its impact on the occurrence of infections. These trials are conducted in at-risk populations. Vaccine candidates previously compared with placebo will in future have to be compared with strategies with demonstrated efficacy (particularly PrEP).

Who may participate in a clinical trial of a preventive vaccine against HIV? Become volunteer