The battle against HIV, which has taken a back seat during the Covid-19 pandemic, returned to the fore in France Friday during the 28th edition of Sidaction, an annual televised fundraising event happening through Sunday.

The virus that causes AIDS has claimed the lives of more than 32 million people worldwide since the 1980s. Scientists are continuing their research and creating new initiatives to develop a vaccine to overcome this scourge.

The health crisis caused by the coronavirus pandemic has slowed research, even though several trials have recently relaunched, Bruck-Landais, the director of the research and health division at Sidaction, said.

The subject of a vaccine strategy has mobilised research since the beginning of the HIV epidemic, Bruck-Landais said, mentioning “many failures, and vaccine projects or vaccination strategies that have since evolved thanks to our greater knowledge of the virus and the immune system”.

These developments now make it possible to test complete strategies capable of circumventing the problems of HIV, an unstable virus that mutates and from which many subtypes arise.

Several trials and ‘a rather innovative strategy’

So what is the state of research today? “There is a very advanced trial in phase 3 that we expect results from in 2022,” Bruck-Landais said. This trial is testing a “mosaic” strategy, making it possible to use different pieces of the HIV virus, which correspond to different subtypes, with the aim of being able to prevent most of the virus that is in circulation worldwide.

A trial for a preventative vaccine launched in France by the Vaccine Research Institute, a laboratory created by the French National Agency for Research on AIDS and Viral Hepatitis (ANRS) and the University of Paris-Est Créteil, is among other trials currently in phase 1.

This trial “is testing a rather innovative strategy to optimise dendritic cells: Central immune cells that orchestrate our immune response”, Bruck-Landais explained. The idea is to “target these cells so they can recognise HIV viruses and then present them with antigens in order to stimulate antibody production”.

The Vaccine Research Institute launched a call for volunteers in late February and planned three stages of recruitment. Its trial aims to “test the safety of the vaccine”, Bruck-Landais said, and its goal for now is to discover whether the vaccine produces an immune response and whether the planned doses induce side effects. The first volunteers will receive their injections in mid-April.

‘Interactions and lessons to be learned’

While the research is continuing, it has faced difficulties linked to the health crisis. “Trials have been interrupted or slowed down,” Bruck-Landais said, particularly because it became impossible to monitor thousands of participants due to “travel problems and health measures”. Expected results have thus been delayed.

However the research director noted a positive corollary to the health crisis: It encouraged HIV and Covid-19 researchers to collaborate. This collaboration in particular opened up new avenues of study on messenger RNA technology, which is used for the Pfizer-BioNTech and Moderna Covid-19 vaccines. “This technology has never been tested for HIV, but researchers have been studying it for several months to apply it to HIV,” said Bruck-Landais.

The two viruses are nonetheless very different, she said, noting that vaccine strategies tested for HIV have not been successful, whereas several Covid-19 vaccines have been found in record time.

“One is the coronavirus – Sars-CoV-2 – and the other is a retrovirus – HIV,” she explained. “HIV mutates enormously. In each viral cycle, every time it multiplies, it generates at least 20 mutations, and on top of that, there are at least four different subtypes circulating in the world.

“The vaccine strategy is less complicated when it comes to getting the immune system to recognise a single virus than thousands of variants and at least four subtypes.”

The state of HIV research has benefitted coronavirus research, she added. “Vaccine strategies that were tested for HIV and did not work are being used for Covid-19 vaccines, including the adenovirus vaccine (used by AstraZeneca and Johnson & Johnson).

“There are interactions and lessons to be learned on both sides.”

In France, 173,000 people live with HIV, and an estimated 24,000 more are unknowingly infected. However, a drop in screenings for HIV during the Covid-19 pandemic – around 650,000 tests in 2020 according to Santé Publique France, the national health agency – has raised fears of an epidemic rebound by 2022.

Culled from France 24