Unlike most flu vaccines, which target the head of proteins, the experimental compound focuses on the stems, which are known to mutate less frequently. An approach that should provide universal immunization in the longer term. Explanations.
An innovative approach
Even after decades of research and global vaccination strategies, the seasonal flu continues to kill hundreds of thousands of people every year. The ability of the virus to mutate and escape our vaccines implying a constant search for the latest strains circulating in the population. Designed to train the immune system to recognize a protein on the surface of the influenza virus called hemagglutinin (HA), the compounds available on the market indeed target its head, known to mutate rapidly, which induces an annual reformulation of the latter.
Conversely, the ” rod »Of the HA protein is much less subject to mutations and also has the advantage of not varying from one influenza subtype to another, which means that it is the perfect target for a universal influenza vaccine .
” This genetic modification, or mutation, of the virus results in immunity to specific strains of the influenza virus only, requiring frequent reformulation and re-administration of seasonal vaccines. “, Explain Peter Palase, co-author of the new study, highlighting how this new type or influenza vaccine differs from previous technologies. ” Our chimeric HA vaccine, on the other hand, is directed to the proximal part of the HA protein, or stem, which has been shown to broadly neutralize various strains of influenza viruses, both in animal models and in humans.. “
Very encouraging preliminary results
Several types of universal stem-targeting influenza vaccines are currently in development. One method uses the technology ofRNA messenger to help the immune system recognize HA rods, while another technique uses nanoparticles to induce effective protection. Although several phase 1 clinical trials aiming to test the safety and efficacy of these experimental compounds are being carried out, no results have so far been communicated.
Recently published in the journal Nature Medicine, this work is therefore the first to report positive results for a universal influenza vaccine targeting HA stems in a phase 1 trial. Conducted by researchers at theIcahn School of Medicine at Mount Sinai, this involved 65 healthy adult subjects and showed the compound to be safe and induce a strong immune response.
According to the researchers, the antibodies produced after administration of the vaccine persisted for at least 18 months. This suggests the possibility of lasting protection against all strains of influenza, and the end of annual vaccinations.
“A major advance compared to conventional vaccines”
It should be remembered, however, that phase 1 clinical trials are not designed to assess the level and duration of vaccine protection against infection, but rather its safety and the initial immune response. But from this point of view, the data collected so far is very promising and offers all the signs to support the further development of a universal influenza vaccine.
” An influenza vaccine resulting in broad immunity would likely protect against any emerging virus subtypes or strains and significantly improve our pandemic preparedness. “, valued Florian Krammer, co-author of the study. ” Our chimeric compound based on hemagglutinin constitutes a major advance over conventional vaccines which are often poorly adapted to the strains of viruses in circulation, which undermines their effectiveness. In addition, the annual revaccination of individuals turns out to be a huge and expensive undertaking.. “