An experimental vaccine against the AIDS virus shows promising results

Human Immunodeficiency Virus (HIV) was officially identified in 1983. To date , there is still no vaccine but after 35 years of research, a new study suggests a bit of optimism. An experimental vaccine tested on macaques as well as on humans led to a robust immune response. But new tests are expected and caution remains in place.

The results of these tests are published in an article published in the journal The Lancet . The clinical trial named APPROACH ran from 2015 to 2016, and included 393 healthy human subjects from Africa, Thailand and the United States. Seven groups received different combinations of the vaccine four times over a 48-week period while the control group received a placebo.

Results on humans, but also on macaques

At the end of the trial, all subjects who received a vaccine produced an immune response and the majority of them they showed good tolerance to treatment. Only five participants experienced adverse events such as abdominal pain or diarrhea but no more serious effects. An encouraging result, but one that does not guarantee the effectiveness of the vaccine.

To consolidate this assessment, another study was conducted in parallel on Rhesus macaques, to which strains of the same vaccine were injected. Since the simian immunodeficiency virus is very similar to that of humans, the efficacy of the vaccine in monkeys would be a good indicator. And again, the molecule seems to have had its effect: the most successful vaccine cocktail has protected from infection two thirds of the 72 macaques tested in this study.

After the success of these initiatives, a second battery of tests has already been launched on a group of 2,600 women in Sub-Saharan Africa. As the experts explained, the promising results of these trials would certainly be due to the new approach taken in the making of the vaccine but caution is still needed.

A vaccine containing several strains of HIV

This is not the first time a vaccine has been tested against HIV. For the moment, however, previous attempts have failed to provide long-term, real-world protection. Most of the treatments developed so far have been based on a specific HIV strain in one region of the world. The problem is that the rapid mutations of the virus have the effect of rendering the treatments obsolete.

But this new vaccine does not repeat this same pattern. It is called "mosaic" because it contains strands of different viruses combined together. This triggers an immune response against a wide variety of HIV strains. Despite this new approach, researchers remain cautious in their interpretation of results.

One of the authors of the study, Professor Dan Barouch of Harvard Medical University, told CNN : " I would say that we are satisfied with our results so far, but we must interpret the data carefully ". It tempers expectations around this experiment: " We must admit that developing an HIV vaccine is an unprecedented challenge, and we are not sure that this vaccine effectively protects humans ".

Nearly 37 million people infected with HIV

If the road is still long, the production of a vaccine remains paramount in the fight against AIDS. According to figures from UNAIDS, a UN program to coordinate the fight against HIV, nearly 37 million people were living with HIV or AIDS in 2016, including more than two million children. An estimated 1.8 million people newly infected with the virus in 2016.

Although the effectiveness of treatments has increased since the onset of the disease in the early 1980s, the search for a vaccine has remained unsuccessful. As Professor Barouch pointed out, " it will be only the fifth HIV vaccine concept whose effectiveness will be tested in the 35-year history of the epidemic "