RNA technology to enable a universal flu vaccine

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Influenza poses a constant threat to public health.

Both for the seasonal epidemics that, according to the WHO, cause between

and more than half a million deaths each year in the world;

as well as the risk that, due to its ability to 'change face', a new influenza virus will manage

.

For years, in order to face this threat, different groups of scientists have been looking for a way to develop a universal flu vaccine that

and offer a protective shield prepared to face any attack.

Research published this Thursday in 'Science' brings us one step closer to that goal.

According to their data, American scientists have managed to develop a universal vaccine against influenza that, in animal models, is protective.

The development of this proof of concept has been carried out

, the same one that was used for the first time in Covid vaccines.

This approach has allowed these scientists led by Claudia Arevalo, from the Institute of Immunology of the University of Pennsylvania (USA) to create a vaccine that contains

corresponding to all subtypes of influenza A and B viruses that have been identified.

Currently, two types of influenza A viruses,

and

, and two lineages of the type B virus, circulate in humans. Seasonal vaccines, whose effectiveness is limited, target variants of these four types of virus (with a maximum of 4 antigens in the product).

However, there are 16 other A virus subtypes that, although they do not affect humans, have a

Arevalo's team has managed to develop a formulation that includes antigens from these 20 subtypes.

Using messenger RNA technology, they have been able to encapsulate specific proteins of these 20 subvariants in a single product - specifically their hemagglutinins, proteins that constitute the main sites of antigenic recognition by the immune system.

Good results in preclinical trials

In experiments with mice and ferrets, the researchers were able to verify that the vaccine induced the animals to

against each subtype that remained in their bodies four months after vaccination and were more numerous than those obtained with vaccination. conventional.

After subjecting them to a challenge with influenza viruses, the researchers also verified that the vaccinated animals presented protection against the pathogens.

"Our study indicates that

by simultaneously inducing antibodies to multiple antigens," the researchers write in the scientific journal.

The article is accompanied by a comment from Alyson Kelvin and Darryl Falzarano, from the University of Saskatchewan (Canada), who

such as the challenge that product approval poses for regulatory authorities which is directed in part at viruses that currently do not circulate in humans.

Raúl Ortiz de Lejarazu

, director emeritus of the National Influenza Center of Valladolid, highlights, along the same lines, the long road that still remains to be traveled before this vaccine can demonstrate, if it does, its usefulness in humans.

"

", he emphasizes.

"It is very important to achieve universal protection against multiple subtypes, but then there are many other questions to find out, such as the duration of protection, the response in different age groups, etc. This experiment is a proof of concept ", Add.

"The researchers present a strategy similar to that used to generate the mRNA vaccine against SARS-CoV-2, but in which they introduce messenger RNA from the 20 versions of the hemagglutinins of type A and B influenza viruses that could give rise to a virus with the possibility of infecting us.The

and ferrets (animal models widely used to study influenza) against different subtypes of influenza viruses. flu, including viruses that are far from having a significant similarity with the sequences included in the vaccine", he pointed out, in statements to the Science Media Center Spain

, virologist and professor of Microbiology at the CEU San Pablo University.

"All of this implies that it is possible to potentially have a universal vaccine that is easy and quick to build that

. Although they do not discuss it in the article, this vaccine could also have very useful in preventing the flu in animals that may suffer from it, and reducing the risk of zoonoses among animals in a context of global health", adds the scientist, who stresses that "the article does not yet present data on the possible advance of this vaccine to a next phase in humans, where not only the efficacy should be demonstrated, but also the adverse effects, the dose or immunity in the short and long

in protection against disease.

The activation of CD4 T lymphocytes is important for the optimal humoral response exerted by antibodies."

According to the criteria of The Trust Project

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