AFRICA—The trial of an experimental HIV vaccine in Uganda, Tanzania, and South Africa has been halted prematurely, according to Reuters.
According to the trial’s chief investigator, Pontiano Kaleebu, preliminary data indicated that the vaccine would not effectively prevent infection.
This setback is the latest in the ongoing efforts to develop an effective vaccine against the virus.
HIV remains a major global public health issue, having claimed 40.4 million lives so far with ongoing transmission in all countries globally.
There were an estimated 39.0 million people living with HIV at the end of 2022, with about 25.6 million in the WHO African Region.
In 2022, 630 000 people died from HIV-related causes, and 1.3 million people acquired HIV.
There is no cure for HIV infection; however, with access to effective HIV prevention, diagnosis, treatment, and care, including for opportunistic infections.
HIV infection has become a manageable chronic health condition, enabling people living with HIV to lead long and healthy lives.
The experiment, which began in December 2020 as part of the larger PrEPVacc project, enrolled 1,512 healthy adults aged 18–40 and was initially scheduled to be completed in 2024.
PrEPVacc is a three-in-one trial led by African academics with support from European experts.
The trial planned to test two different HIV vaccine combinations to see if either could prevent HIV infection in at-risk populations.
Participants received injections of either an AIDSVAX regimen combining DNA vaccination with a protein-based vaccine, a CN54gp140 regimen combining DNA, MVA, and a protein-based vaccine, or a placebo (saline). Each regimen or placebo comprised four injections.
The program’s independent data and safety monitoring committee advised withdrawal, citing an inability to demonstrate the vaccine’s efficacy even if the trial continued, according to Kaleebu.
While there are already available medications to reduce the risk of developing HIV and treatments to control the virus, the search for an HIV vaccine remains critical.
Experts believe that a successful vaccine would be critical to eliminating AIDS as a public health threat.
The trial, headed by African academics with assistance from European universities such as Imperial College London, investigated two novel HIV vaccine combinations.
Concurrently, it compared the efficacy of a novel form of oral pre-exposure prophylaxis (PrEP), a medicine that reduces HIV risk, against that of existing drugs. This part of the trial is still going on.
Participants, primarily from high-risk communities such as sex workers, gay men, and fishermen, contributed to the research endeavours.
According to a statement released on Wednesday, the vaccination trial program acknowledged the experiment’s failure as the world’s only surviving active HIV vaccine effectiveness trial.
This finding highlights the significant hurdles to producing an effective HIV vaccine.
Notably, South African researchers halted another trial involving over 5,000 participants in 2020 after tests of a vaccine failed to indicate benefits.