Johnson & Johnson's 'Imbokodo' trial for HIV vaccine fails in sub-Saharan Africa

A clinical trial involving 2,600 young women in sub-Saharan Africa found that Johnson & Johnson's highly anticipated HIV vaccine did not offer adequate protection against the virus, the company told US health officials Tuesday.

Despite its safety and lack of serious side effects, the vaccine was only 25 per cent effective in preventing HIV infection.

Accordingly, the "Imbokodo" trial that began in 2017 has been suspended, and the participants, from Malawi, Mozambique, South Africa, Zambia, and Zimbabwe, will be told if they received the vaccine or a placebo.

A parallel trial will continue in the Americas and Europe, where vaccine compositions and HIV strains differ. This trial involves men engaging in physical relationships with other men and transgender individuals.

Paul Stoffels, chief scientific officer for J&J, expressed his gratitude to the participants as well as company partners.

"While we are disappointed that the vaccine candidate did not provide a sufficient level of protection against HIV infection in the Imbokodo trial, the study will give us important scientific findings in the ongoing pursuit for a vaccine to prevent HIV," he said.

"We must apply the knowledge learned from the Imbokodo trial and continue our efforts to find a vaccine that will be protective against HIV," added Anthony Fauci, director of the US National Institute of Allergy and Infectious Diseases which co-funded the study.

Genetically modified cold viruses are used to transmit instructions for the host to produce "mosaic immunogens" that can cause the immune system to attack a variety of HIV strains.

Additionally, the final two doses contained proteins found in HIV viruses themselves, as well as "adjuvants" that helped to boost the immune system even more.

Trial results were analyzed two years after the first dose was given to the women, aged 18-35.

The study found that 63 placebo recipients and 51 vaccination recipients became infected with HIV, meaning that the efficacy rate was 25.2 per cent.

Preexposure prophylaxis medication (PrEP) was given to trial participants to help prevent HIV infection during the trial.

Medical care and antiretroviral treatment were provided to women who acquired HIV infection.

The quest for a viable treatment continues

Science has made great strides in HIV treatment in the four decades since the first cases of what would become known as AIDS were documented. What was once a death sentence has become a manageable condition.

A daily dose of PreP reduces infection risk by 99 per cent.

Nevertheless, the lack of equal access to medication across the world and even in wealthy countries make a vaccine that is able to ward off infections a high priority.

(With inputs from agencies)