Early-stage HIV vaccine trial starts in South Africa

29 November 2016

New HIV vaccine trial builds on success of 2009 Thai trial that showed 31.2% effectiveness in preventing HIV.

The first large-scale HIV vaccine trial in seven years has launched in South Africa and will test the efficacy of an experimental vaccine regime among adults at a high risk of HIV in the country.

The phase III trial, called HVTN 702, will test the efficacy, safety and tolerability of an experimental vaccine made up of ALVAC-HIV and a two-component protein vaccine. The HVTN 702 trial will build on the positive results of the RV 144 Thai trial with a slight modification in the vaccine to account for the HIV subtype predominant in South Africa.

The RV 144 vaccine trial in Thailand was widely publicised and hailed as an important step in the search for a vaccine. It recruited 16,402 young adults in Thailand and showed the vaccine was 31.2% effective in preventing HIV infection among the participants during the 3.5 years after vaccination, and up to 60% effective in the first year – a modest protective effect for a vaccine.

The new HVTN 702 trial was given the go-ahead after results were released at AIDS 2016 from the small-scale HVTN 100, which showed that the vaccine modification was safe among the 252 study participants, and had similar results to the RV 144 trial.

Importantly for this new research, the study participants of the RV 144 trial were not all at a high-risk of HIV. It is hoped that HVTN 702 can prove effective in the context of a generalised epidemic among people vulnerable to HIV.

"The people of South Africa are making history by conducting and participating in the first HIV vaccine efficacy study to build on the results of the Thai trial," said HVTN 702 Protocol Chair Glenda Gray, M.B.B.C.H., F.C.Paed. (SA). "HIV has taken a devastating toll in South Africa, but now we begin a scientific exploration that could hold great promise for our country. If an HIV vaccine were found to work in South Africa, it could dramatically alter the course of the pandemic."

The study will enrol 5,400 HIV-uninfected, sexually active men and women aged 18 to 35 who are at risk of HIV infection. Results are expected by late 2020.


Written by Caitlin Mahon

Content Specialist - HIV & Sexual Health