Science has been trying in vain for 30 years to find a vaccine for HIV. But for the first time since the virus was identified in 1983, there is hope that a newly developed experimental vaccine might bring the world a step closer to a breakthrough in the battle against AIDS. The clinical trials were launched on November 30 in South Africa.

The new study, known as HVTN 702, will involve more than 5,400 sexually active men and women aged 18-35 in South Africa over the course of four years. It is one of the biggest clinical AIDS trials ever undertaken and the first new human HIV vaccine study in about a decade.

Although antiretroviral medicaments have stopped AIDS from being a death sentence, experts believe that the epidemic can only be stopped with a vaccine.

The 'Holy Grail' of vaccines

Professor Linda-Gail Bekker from the University of Cape Town is the new study's co-chair. She said discovering a vaccine against HIV is very difficult. "Finding a vaccine that really works is like looking for the Holy Grail." She agrees that it is not possible to eradicate the disease completely before there is a vaccine that keeps people from getting infected. "But if we develop that vaccine, it will be a revolution in the war on the epidemic," Bekker said.

There is a reason why South Africa was chosen as the trial site. According to the United Nations AIDS agency, the country has a 19.2 percent infection rate, one of the highest in the world. More than seven million South Africans live with the virus. One thousand people are infected every day. Two thirds of those participating in the new trials are women, considered to be at highest risk.

Researcher Bekker is ambivalent about the choice of South Africa to test the new vaccine: "It is a bittersweet thought, because of the huge prevalence of HIV here. That is bad. But on the positive side, the study is being done here because we can. We have the infrastructure, the experts and the participants who really want to see HIV vanquished."

Criticism of the South African trials

The safety of the "South African" vaccine has already been tested successfully over 18 months on 252 volunteers. The new study now aims to test its effectiveness as a virus-killer. The vaccine has been adapted for the HIV strain prevalent in southern Africa from one used in a trial of 16,000 people in Thailand in 2009. The latter reduced the risk of infection by 30 percent for three-and-a-half years after the first jab.

That is not enough for everybody. Lynn Morris, head of the HIV virology section at South Africa's National Institute for Communicable Disease pointed out that "the results obtained in Thailand are not good enough for a roll-out”, since the minimum bar was set at 50 percent lower risk.

Anthony Fauci, director of the US National institute for Allergies and Infectious Diseases (NIAID), which is taking part in the study, defended the criticism of the efficacy of the new vaccine: "Even a moderately effective vaccine would significantly decrease the burden of HIV disease over time in countries and populations with high rates of HIV infection."

Making progress

Nevertheless, like many of her colleagues, Linda-Gail Bekker is hoping for a real breakthrough. This is important because young people in South Africa do not even discuss the subject anymore: "If we don't pay attention to the epidemic, we'll lose ground. That worries me. It is great to have new impulse in South Africa. I don't doubt that we're making progress," she said.

The new trial is being carried out by the US National Institutes of Health, the South African Medical Research Council, the Bill and Melinda Gates Foundation, Sanofi Pasteur, GlaxoSmithKline and the HIV Vaccine Trials Network. First results of the current trials are expected to be published by the end of 2020.

Jana Genth contributed to this article.