New HIV Vaccine Study Underway in South Africa

A historic clinical trial testing the efficacy of an experimental HIV vaccine regimen gets underway this week in South Africa. Supported by the National Institutes of Health (NIH), the study is the first in 7 years to evaluate this type of vaccine.

The study, called HVTN 702, will test whether the vaccine candidate safely prevents HIV in 5400 men and women from South Africa, where the HIV epidemic is rampant. An estimated 7 million South Africans were reported living with HIV in 2015, and 180,000 died from an AIDS-related illness in the same year.

Participants will be tested with the HVTN 702 regimen, which includes 2 experimental vaccines: a canarypox vector-based vaccine called ALVAC-HIV and a 2-component gp120 protein subunit vaccine with an adjuvant to enhance the body’s immune response. Participants will also be administered booster shots one year after the trial to prolong the early protective effect seen in its predecessor trial, RV144.

The experimental vaccine regimen is based on one investigated in the RV144 clinical trial in Thailand, which noted a most protective effect -- 31.2% at a 3.5 year follow up -- of an HIV vaccine. By adapting the RV144 regimen to the HIV subtype that predominates southern Africa, researchers hope the new vaccine will provide more effective and sustained protective immune responses. The vaccines do not contain HIV.

Study participants will be randomly assigned to either the investigational vaccine regimen or a placebo, and will receive a total of 5 injections over a one-year span. All volunteers will be monitored for safety and offered the standard of care preventing the HIV infection.

The National Institute of Allergy and Infectious Diseases (NIAID) is sponsoring this study and conducting the trial at 15 sites across South Africa. Results are expected in late 2020. A number of other NIAID-supported HIV prevention trials are also being examined throughout southern Africa.