An mRNA flu vaccine has just been developed that could protect against more than 20 different strains of the virus. In the long term, its commercialization would make it possible to better protect populations during seasonal epidemics.
- Seasonal flu is an acute viral infection caused by an influenza virus.
- There are 3 types of seasonal flu: A, B and C.
“Globally, these annual epidemics [de grippes saisonnières] are responsible for approximately 5 million cases of serious illness, and 290,000 to 650,000 deathsaccording the World Health Organization (WHO). Influenza vaccination is most effective when the vaccine viruses match the circulating viruses. Because influenza viruses are constantly changing, the WHO Global Influenza Surveillance and Response System (GISRS) (…) monitors circulating influenza viruses in humans and updates the composition of influenza vaccines twice a year”. But that work could soon be avoided, thanks to a vaccine capable of fighting 20 different strains of the virus.
A vaccine capable of fighting 20 strains of seasonal flu
American researchers have developed this super vaccine to mRNA. For the moment, it is in the state of experimental version. They detail the results of their clinical trials in the journal Science. In animals, this serum has been shown to reduce disease symptoms and protect against death, even when the animals were exposed to different flu strains than those used to make the vaccine.
“The idea is to develop a vaccine that will give people immune memory with various flu strains so that there will be far fewer illnesses and deaths during the next flu pandemic.“, explains Scott Hensley, lead author of this study.
An mRNA vaccine against influenza comparable to those against Covid-19
For their product to be as effective, the scientists integrated immunogens – a molecule that participates in the formation of antibodies – of all known strains of influenza. But researchers warn that the immunity conferred by the vaccine does not prevent all flu viral infections. This one “would be comparable to first-generation Sars-CoV-2 mRNA vaccines, which targeted the original strain of the coronavirussays Scott Hensley. Against later variants like Omicron, these original vaccines did not completely block viral infections, but they continued to provide long-lasting protection against [formes graves] of sickness and death.“
When the vaccine is given, the cells produce copies of a key influenza virus protein, the hemagglutinin protein, for all twenty influenza hemagglutinin subtypes, from H1 to H18 for influenza A viruses. and two more for influenza B.”For a conventional vaccine, immunizing against all of these subtypes would be a major challenge, but with mRNA technology it is relatively easy.“, says Scott Hensley.
High levels of antibodies against all 20 flu strains with vaccine
Thus, during their clinical trial, the researchers observed that the mice had high levels of antibodies against the 20 strains of influenza after the injection of the serum. And these remained high for at least four months.
Currently, researchers are conducting clinical trials on humans. Ultimately, the objective would be to be able to market this vaccine and thus better protect populations against seasonal flu epidemics. In France, 2 to 8 million people are affected each year according to I‘Pastor Instituteand the excess mortality is 10,000 to 15,000 deaths, mainly in frail subjects.
