A new vaccine to treat HIV is set to be tested in South Africa this year.

The development was revealed during the ongoing 21^st International AIDS Conference (AIDS2016) in Durban South Africa following results from immunology studies.

Interim immunology studies for the HVTN 100 conducted by US-based HIV Vaccine Trails Network (HVTN) and South African research sites showed that the vaccine tested the immune responses of South African volunteers to a modified version of the RV144 regimen, the only HIV vaccine regimen to show efficacy to date.

The original RV144 vaccine reduced the HIV infection rate among study participants in Thailand by 31 per cent over 3.5 years.

HVTN 100 protocol chair, Linda-Gail Bekker, said that the HVTN 100 used the same vaccines that RV144 tested, but made them specific to the Clade C subtype of HIV, which is widespread in southern Africa.

"We also changed the adjuvant used with one of the vaccines, with the goal of eliciting a more powerful immune response, and added a booster injection to prolong the period of protection,” said Bekker, who is also Deputy Director of the South Africa based Desmond Tutu HIV Centre.

Interim results from HVTN 100 provided the green light for a Phase III efficacy trial on the modified RV144 regimen although criteria for the go-ahead centred on the percentage of HVTN 100 vaccine-recipients who displayed a range of immune responses, and the strength of those responses.

"All the criteria were met unequivocally and, in many instances, the HVTN 100 outcomes exceeded both our own criteria and the immune responses seen in RV144,” Bekker concluded.

Larry Corey, HVTN Principal Investigator, elaborated that although these vaccines were previously designed for SouthAfrica, they exceeded the criteria to provide ground for other trials.

"It is gratifying to see vaccines that were designed and manufactured specifically for South Africa meet and even exceed the criteria established to advance them into the large efficacy trial. HVTN 702 is a pivotal study that could lead to a licensed HIV vaccine in South Africa – the first preventive HIV vaccine worldwide,” said Corey.

HVTN 702, a placebo-controlled study, is set to begin before the end of 2016. 5,400 HIV-negative men and women at 15 research sites across South Africa will be enrolled. 

Participants will receive five injections over the course of a year and will be followed-up for two years more to establish whether the vaccine elicits a sustained protective effect.

The trial will also seek to confirm earlier findings from HVTN 100 that the modified RV144 regimen is safe.