Activists demanding access to treatment. (Photo Courtesy Sarah Marcel/IRIN)

Cape Town — The discovery of a safe, effective HIV/Aids vaccine will mark the biggest achievement in modern world history, says Medical Research Council president Professor Anthony Mbewu.

He was speaking Crossroads yesterday at the launch of the country's first phase of human clinical trials for two South African-produced HIV-Aids vaccines.

National Science and Technology Minister Naledi Pandor and Deputy Health Minister Dr Molefi Sefularo also attended the launch of the SA Aids Vaccine Initiative (Saavi) 102/HVTN 073 trials at the Emavundleni Prevention Centre.

The trials are being conducted by Saavi, the HIV Vaccine Trials Network (HVTN) and the US National Institute of Allergy and Infectious Diseases (Niaid), which is part of the US National Institute of Health.

The vaccines were developed by researchers at UCT.

While there have been other vaccine trials in the country, this is first time two locally developed vaccines are being tested in clinical human trials.

There will be 36 trial participants in Crossroads and Soweto.

It was conceded that although the vaccines were only being tested, it was nonetheless a move in the right direction.

Sefularo said the cost of anti-retroviral medication was high, thus increasing the need for a vaccine.

Dr Anthony Fauci, the head of the Niaid, which sponsored the trials, said South Africa was proving to be a useful ally in the quest for a vaccine.

The trial participants were also keen to be a part of the ground- breaking move.

Wanda Mbele said he was "quite excited", adding that he wanted to help prevent the rapid spread of the illness, especially among young people.

Elise Levendal, interim Saavi director, said the trials had very strict inclusion and exclusion criteria. She said the actual trials would last a year, with another year being spent on analysing the data.

Study vaccines are designed to look like HIV structures. By doing this, the vaccines could cause a response from the person's immune system. The immune system may then learn to recognise HIV, without actually being exposed to the virus. This way, the trial participants' immune systems may be able to respond if they are exposed to the virus.

At this stage it is not known whether the vaccines will increase, decrease or not change a trial participant's chances of being infected if exposed to the virus.