Will we ever be able to protect ourselves against HIV?
For ten years, the eminent professor of immunology, Yves Lévy, former boss of Inserm, has been trying to develop a preventive vaccine.
As World AIDS Day takes place this Thursday and 4,900 people have discovered their HIV status in France in 2020, the director of the Vaccine Research Institute (VRI) and co-founder of the LinKinVax biotech tells us about its latest "promising" results.
You are using totally new technology.
What is it about ?
Professor YVES LEVY.
Given the complexity of HIV, we thought we had to fight it differently.
In recent years, we have studied at length how it works.
To counter it, the key element is to precisely target the dendritic cells.
When a vaccine, whether an inactivated virus or fragments, is administered in the body, they are the ones who send the orders to the immune system.
Alerted, he will then make weapons to defend himself.
It may take time for the message to reach them.
Thus, our injection sends the information directly to them thanks to a kind of missile, an antibody which targets a receptor on the surface of these cells, on which we have attached virus fragments.
They are immediately activated!
Where are they?
You have them everywhere, in the skin, the bronchi, the mucous membranes, the digestive tract… The dendritic cells patrol the whole body and are able to capture, first, the microbes, which penetrate into the organism.
At that time, they present them to the immune system, which will react.
If one day, HIV tries to infect cells, the body will be ready to fight it because it will have kept the memory.
What do your test results show?
We injected three doses, in prevention, to 72 volunteers, not at risk, in France and Switzerland that we followed for a year.
After eight years of research, we succeeded in phase 1-2, which shows that our vaccine is well tolerated and that it induces an interesting immune response.
It is enormous !
We have just passed a crucial stage.
But there remains a major unknown: the body certainly reacts, but will its defenses really protect it when it is infected with HIV?
We don't know yet.
For this, a third phase of testing is needed with at-risk populations: sex workers, male homosexuals, women in Africa.
If this protection works, when will this vaccine be available?
It depends on the results of the phase 3 trials that must be conducted.
We won't have them for two to three years.
We are also developing this technology against other viruses.
Each time, we keep the missile system but we change the virus fragments that we want to target, in other words, we modify the cartridge, the weapon remains the same.
Thus, a trial to test two vaccines against Covid will start in 2023, another against throat cancer linked to the papillomavirus.
For the moment, it is on HIV that we have made the most progress.
Read alsoWhy was no vaccine against AIDS ever found, when it only took a few months for Covid-19?
Failures have been linked for 40 years.
Why is it so complicated to develop an antidote?
Finding an HIV vaccine is a real challenge!
If our strategy proved ineffective, we ourselves would have worked for ten years for nothing.
It is not a virus like the others.
In general, a microbe multiplies in your body, the antibodies block it and it ends up being eliminated, as is the case with the flu.
There, it is different, the HIV infects you then it penetrates, in a few hours, in your chromosomes!
You keep it.
Then it mutates at full speed, much faster than SARS-CoV-2.
It also evades the immune system.
Finally, he attacks her!
But you know, forty years of research is not that long in the history of medicine.
A vaccine against tuberculosis has been sought for more than a century, and for fifty years for hepatitis C.
Is your antidote the only promising candidate?
Since 2009, a single phase 3 trial has shown that an experimental vaccine was capable of reducing the risk of becoming infected by 30%.
Unfortunately, attempts to reproduce these results have been unsuccessful.
It is clear that nothing worked.
There are still around 20 trials ongoing around the world, at an early stage, including ours.
Our particularity is that the strategy is completely innovative.
It is a new hope.