What the nasal spray vaccine could change in the fight against Covid-19

While nearly 70% of the French population is fully vaccinated, according to figures from the health authorities as of September 12, 2021, vaccination alone will not be sufficient to stop the Covid-19 pandemic and prevent further waves. All the more so in the face of the Delta variant, according to the latest models from the Institut Pasteur.

So, how to get out of this health crisis? What if the solution was to a new vaccine, as a nasal spray, for a “ mucosal immunity ‘ ? This is what researchers from the University of Tours and the National Research Institute for Agriculture, Food and Environment (INRAE) of Nouzilly (Indre-et-Loire) are banking on, who have announced encouraging preclinical results on September 9, 2021.

#RP_INRAE Positive preclinical results for a #vaccine # COVID19 nasally with @UnivTours

▶ ️neutralize the virus when it enters
▶ ️blocks contagiousness
▶ ️effective against variants

??100% Frenchhttps://t.co/UGvpw2pCGH

Pictures @B_NICOLAS_INRAE pic.twitter.com/zulVSvpqsu

– INRAE ​​(@INRAE_France) September 9, 2021

What is mucosal immunity?

With their nasal spray vaccine, researchers are banking on the development of a mucosal immunity facing the virus, in addition to the general immunity that it develops.

Because the mucous membranes (nose, mouth, etc.) have an immune system in their own right, which can constitute “a first line of immune defense” against a virus such as SARS-CoV-2.

“The particular immunity of these mucous membranes is due to the specificity of certain antibodies (immunoglobulins A), which will prevent the virus from infecting cells”, explains to actu.fr Nathalie Mielcarek, research director at Inserm, who is working on a nasal vaccine against whooping cough at the Lille Infection and Immunity Center.

Why is a nasal spray vaccine interesting?

Unlike intramuscular vaccines injected using a syringe, such as Pfizer, Moderna, AstraZeneca or Janssen, the vaccine administered by the nasal route is, on the one hand, less invasive.

And above all, it has the advantage, while protecting symptomatic forms, of “avoiding the presence of viruses in the nose, the initial stage of infection, the entry point and place of multiplication of the virus”, explains the Inrae’s BioMAP research team, which developed the vaccine candidate.

By virtue of its properties, such a vaccine would allow a ” early neutralization of the original virus and its variants, blocking any risk of contamination by a vaccinated individual “.

When you are vaccinated this way, if you catch the virus it will be attacked very quickly, greatly reducing the viral load which will infect the cells. Two consequences: much less virus in the lungs, which reduces inflammation and severe forms; and much less virus to transmit, the person becomes much less contaminating.

What is the difference with other vaccines?

Technically, this nasal anti-covid vaccine candidate uses proteins, including those of the SARS-CoV-2 virus, encapsulated in nanoparticles and then diffused through the nasal route, which gives local protection against the virus.

The vaccine, made up of the Spike protein and viral proteins not subject to mutation, would make it possible to be protective regardless of the viral mutations and the circulating strain of coronavirus.

Conversely, current vaccines such as Moderna, Pfizer or Astrazeneca develop antibodies and a general immune system response, allowing to reduce the viral load and to fight against the disease and its serious forms. But these vaccines do not stop the virus from spreading.

An advantage of nasal spray also defended on Twitter by Rémi Salomon, president of the Medical Commission for the establishment of Public Assistance-Hospitals of Paris (AP-HP).

The COVID vaccine administered by nasal spray, a solution that would provide better local immunity (nasal mucosa) than vaccines administered intramuscularly. These give good general immunity through white blood cells and antibodies ⤵️ 1/4

– Rémi Salomon (@RemiSalomon) September 9, 2021

Will the current vaccines eventually be replaced by this “100% French” nasal spray?

For the moment, it is still too early to say, the results, although encouraging, are only at the pre-clinical stage.

Successfully tested on animals, the vaccine must still undergo a whole series of tests, especially on humans, and if necessary, obtain the green light from the health authorities, even if the team of researchers wants to be full of ‘hope.

These results, which are very predictive of the efficacy of a vaccine in humans, lead to the conclusion that contagiousness between individuals has been completely abrogated.

Remember also that this vaccine, in the trial phase, is not the only one. It is the 8th vaccine for nasal administration in preparation in the world, listed by the World Health Organization, “and the only French”, rejoices the BioMap team.

TO the Institut Pasteur de Lille, research for such a vaccine also continue to continue, after initial tests carried out at the end of 2020 and deemed inconclusive.

Inrae research offers “very good results in terms of protection and contagiousness”, recognizes Nathalie Mielcarek, for whom this type of vaccine is intended to develop, in addition to current vaccines “extremely effective”.

The Covid-19 has highlighted the importance of protecting oneself against the disease, of course, but also against its transmission.

Who could it be addressed to, and for what use?

If it were to be marketed, the vaccine would be administered “using a small adapter placed at the end of a syringe without a needle allowing ideal distribution within the nasal cavity”, specify the researchers. Pre-clinical tests have shown efficacy of the vaccine after two “injections” spaced 3 weeks apart.

This vaccine could be aimed at unvaccinated populations, to protect against severe and moderate forms of Covid-19. It could also be used “Vaccine booster for the population already vaccinated in order to avoid the transmission of the disease”.

Non-invasive and requiring few logistics, this simple vaccination system would make it possible to distribute the vaccine system more widely in Europe and beyond.

Note that this vaccine can “potentially be stored for several years at four degrees, for several months at 20 degrees, which will require much simpler logistics,” explains Isabelle Dimier-Poisson, professor responsible for the research team.

According to the researcher, the vaccine could also be accessible to children under 12 years old or even to certain people refractory to an injection.

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Could it be rolled out en masse like other vaccines?

For this nasal vaccine, clinical trials (human) are scheduled for the second half of 2022, with a view to possible marketing in 2023.

If these tests prove to be conclusive, it will then be for the health authorities to decide what is the place of this vaccine in the strategy to fight against Covid-19. With the hope, this time, of a real return to normal life.

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