Here’s why South Africa’s radical HIV vaccine trial has been terminated

The global search for a HIV vaccine has been dealt a heavy blow, following the immediate cancellation of a clinical trial concerning HVTN 702 in South Africa.

While initial tests, which began in October 2016, held promise to puncture the AIDS halt epidemic, moving further along the human testing phase than any trial before, dreams were dashed in January 2020, when independent observers noted the projects failures.

The African Medical Research Council (MRC) reported that the trial, which cost an estimated $104 million and was due to run until 2020, would be terminated following critical feedback from the Independent Data and Safety Monitoring Board (DSMB). The continuation of the trial was described as ‘futile’.

The National Institute of Allergy and Infectious Diseases (NIAID), which had endorsed the ground-breaking clinical trial and oversaw the administration of vaccinations to sexually active, HIV-negative men and women, mourned the termination of the project but remained ‘hopeful’ that immunization could be achieved in future endeavours. NIAID Director Anthony Fauci said:

“Research continues on other approaches to a safe and effective HIV vaccine, which I still believe can be achieved.”

HIV vaccine trial: The results

The testing of HVTN 702 — also known as Uhambo — was based on previous studies in Thailand, as part of the RV144 project administered by the U.S. Military HIV Research Program in conjunction with the Thai Ministry of Health. Adaptations were made to target the HIV subtype Clade C which is most common in Southern Africa.

A total of 5 407 HIV-negative South Africans, men and women between the ages of 18 to 35, were enrolled in the clinical trial. Studies were conducted at 14 sites across South Africa where volunteers randomly received the investigational vaccine regimen or placebo injections. The test group received six injections over an 18 month period.

In January 2020, preliminary results painted a grim picture of the vaccine’s ability to prevent HIV infection. Two fundamental findings typified the trial’s failure:

• 129 HIV infections occurred among the 2 694 volunteers who had been administered the investigational vaccine regimen
• 123 HIV infections occurred among the 2 689 volunteers who had received the placebo

HVTN 702 Protocol Chair, Glenda Gray, noted that while she was devastated by the trial’s outcomes, the South Africans who volunteered to partake in the study were to be commended. Gray said:

“The people of South Africa have made history by answering this important scientific question. Sadly, we wish the answer was different.”

Importantly, findings confirmed that the HVTN 702 trial had no adverse effects on participants but simply had not shown any efficacy.

HIV and AIDS in South Africa

South Africa has the highest number of people inflicted with HIV of any country in the world. According to UNAIDS, more than 7 700 000 people are currently living with HIV which amounts to almost 20% of the entire adult population.

While there has been progress relating to the decrease in HIV-related deaths, largely thanks to medical advancements and the availability of Antiretroviral treatments, South Africa is still attempting to break the pandemic by achieving the following goals at the end of 2020:

• 90% of people living with HIV will know their HIV status
• 90% of people who know their HIV-positive status will be accessing treatment
• 90% of people on treatment will have suppressed viral loads

Although recent statistics indicate that approximately 90% of people living with HIV do know their status, progress in relation to access to treatment and viral suppression is sorely lacking.