Vaccine nasal sprays aim to “close the door” to the virus

Paris – Could immunization to COVID-19 directly into the nose – the area of ​​the body through which it is most likely to be transmitted – help beat the pandemic?

The World Health Organization says clinical trials are underway to evaluate eight nasal spray vaccines targeting COVID-19.

The most advanced effort to date by Xiamen University of China, University of Hong Kong and Beijing Wantai Biological Pharmacy has completed Phase 2 trials.

“When the virus infects someone, it usually enters through the nose,” said researcher Nathalie Mielcarek, who is working with the Institut Pasteur in Lille to develop a nasal spray vaccine against whooping cough.

“The idea is to close the door.”

An article published in Scientific American in March urged development of nasal spray vaccines because they have an immediate effect on the virus in the mucus of an infected person.

There, they trigger the production of an antibody called immunoglobulin A, which can block infection.

“This overwhelming response, called sterilizing immunity, reduces the risk of people passing the virus on,” the article said.

Currently available vaccines offer strong protection against severe forms of COVID-19 but are less reliable in preventing the spread of the virus.

Boosting immunity directly in the nose “reduces the risk of infecting other people,” Mielcarek said.

“From there, you have less virus infecting the lungs and therefore fewer severe cases since the viral load is lower,” she added.

An article published in March by Gavi the Vaccine Alliance noted other benefits, including the fact that the sprays do not need refrigeration and do not need to be administered by medical professionals.

“People could administer it themselves at home,” the article said, adding “they are probably more popular for the millions of people who don’t like needles.”

And in a French study on mice presented last week, 100% of subjects vaccinated with the spray survived infection with COVID-19 while all unvaccinated mice died.

“Vaccinated animals… showed low levels of the virus, so they are no longer contagious – this is one of the advantages of nasal spray,” said Philippe Mauguin, CEO of the French institute which hopes to patent the vaccine.

Isabelle Dimier-Poisson, who led the research, has high hopes.

“It could allow us to come back to life before the pandemic, without social distancing, and without masks,” she said.