Replacing the vaccine needle with an injection into the nose: the key to eradicating Covid-19?
Several laboratories are currently working on nasal vaccines. As their name suggests, they are injected directly into the nose, and not into the muscle of the arm like all the vaccines currently used in France. If this method of nasal injection is little known to the general public, it seems that it makes it possible to fight effectively against the virus.
100% survival in mice vaccinated and infected with Covid-19
In early September, INRAE and the University of Tours filed a patent for a nasal administration vaccine candidate after promising results on the animals.
According to the head of the BioMAP research team, Isabelle Dimier-Poisson, the tests showed “100% survival” on mice vaccinated then infected with Covid-19, against “100% mortality” on non-mice. vaccinated.
Vaccinated animals are 100% protected against the symptomatic forms and a fortiori the severe forms of the virus. And they have very few viruses so they are no longer contagious, that’s one of the interests of the nasal passage.
Philippe Mauguin, CEO of Inrae
The advantage: a double layer of protection
How to explain these encouraging results? In an article published in July in the scientific journal Science, researchers Frances Lund and Troy Randall recalled that compared to intramuscular vaccines, intranasal vaccines offer two additional layers of protection.
The first is IgA, a type of antibody that plays a crucial role in the immune function of the mucous membranes. The second is the creation of “memory” B and T cells which reside in the respiratory mucous membranes and form a barrier against infection in these areas.
“When the virus infects a person, it generally enters the nose, the idea is to close the front door”, decrypts Nathalie Mielcarek, research director at Inserm.
With intramuscular vaccines, we manage to induce an immune response in the mucous membranes but not very long and not very strong, it is more interesting to immunize at the nasal level.
Morgane Bomsel, immunologist, research director at the CNRS at the Institut Cochin
Fight against the spread of the virus
Faced with Covid-19, the vaccines currently on the market provide strong protection against severe cases of the disease, less against the risk of transmission. By vaccinating in the nose, the idea is to fight against the virus but also against its spread.
We have less virus which subsequently infects the lungs, therefore fewer serious forms since the viral load is lower, and also less risk of transmission to other people that we might cross.
Tests still necessary before going to market
But these nasal vaccines remain, for the most part, yet to be evaluated in humans. According to the WHO, eight nasal vaccines are currently under clinical evaluation, that is to say in testing in humans, the most advanced being that developed by a group of universities and Chinese company. Several dozen vaccines are also in preclinical stages.
Still, the laboratories need funding to advance their research on these vaccines. If in rich countries, the majority of the population has already received first generation vaccines, researchers highlight the interest of a booster with these nasal injections, which would be a “booster” to extend immunity induced by the first intramuscular vaccines.
It would not, however, be the first time that a nasal vaccine has been used on a large scale to protect against disease. In the UK, a nasal spray is offered every year to immunize children against the flu, according to the National Health Service (NHS), UK Social Security. About ten years ago, intranasal vaccines were also administered in India to combat the H1N1 virus.