(Washington) A vaccine, but no needle. Since the start of the pandemic, plans to vaccinate against COVID-19 using transdermal patches have multiplied, testifying to a movement that could well revolutionize the way vaccines will be administered in the future.
The technique will be able to avoid a few bursts of tears for certain children, who are not very fond of syringes. But above all, it has many other advantages, particularly in terms of distribution, or increased efficiency.
A study on mice, published Friday in the journal Science Advances, showed promising results.
The stamp used: a square of 1 cm by 1 cm, in plastic, with on its surface more than 5000 tiny peaks, “so small that you cannot even see them”, described to AFP the Dr David Muller, study co-author and virologist at the University of Queensland, Australia.
QUEENSLAND UNIVERSITY PHOTO, VIA AGENCE FRANCE-PRESSE
The patch is a 1 cm by 1 cm square, plastic, with thousands of tiny tiny peaks on its surface, invisible to the naked eye. We see it in its applicator, which is shaped like a hockey puck.
These tips have been coated with the vaccine, which is deposited on the skin when it penetrates it.
The patch is applied using an applicator (which is shaped like a small hockey puck). The sensation is only that of a flick, or a piece of scratch pressed against the skin.
The researchers used here a so-called subunit vaccine, reproducing a protein specific to the SARS-Cov-2 virus: the protein spike.
Mice were vaccinated with the patch (applied for two minutes), and others with needles.
For the first, “we obtained a very strong antibody response, including in the lungs, which is important for COVID-19” detailed the researcher. The results obtained have largely “surpassed” needle vaccination, he says.
Secondly, the efficacy of a single dose was evaluated. By using an adjuvant, which serves to stimulate the immune response, the mice “did not get sick at all”.
Easy to administer, no need for nurses
Why such efficiency?
Vaccines are usually given by intramuscular injections. However the muscle does not present “many immune cells, required to support the vaccine”, compared to the skin, explains Dr Muller.
In addition, the insertion of the tips of the patch causes tiny injuries, which alert the body of a problem and thus stimulate the immune response.
For the scientist, the advantages of the technique are clear: first, the vaccine can remain stable for a month at 25 ° C, and a week at 40 ° C (compared to a few hours at room temperature for the vaccines from Pfizer or Moderna ). This allows less dependence on the cold chain, which constitutes “a challenge for developing countries”.
In addition, “it’s incredibly easy to administer”: no more need for trained nursing staff.
Burak Ozdoganlar, professor of engineering at Carnegie Mellon University in Pittsburgh in the United States, has also been working on these transdermal patches since 2007.
Much less vaccine needed
And he sees another advantage: “a smaller amount of vaccine, delivered precisely into the skin, can produce an immune response similar to an intramuscular injection,” he emphasizes. An important factor as countries fight over doses.
Professor Ozdoganlar can produce 300 to 400 stamps per day in his laboratory.
But he regrets not being able to test the messenger RNA vaccines from Pfizer or Moderna, because they are not authorized to do so by these two pharmaceutical companies.
The stamp used in the study released Friday was made by Australian company Vaxxas, the most advanced in the industry. Phase 1 clinical trials are planned from April.
Two other American companies have also launched: Micron Biomedical, and Vaxess.
The latter, founded in 2013 and based in Massachusetts, is working on a slightly different stamp. The vaccine is placed in the very tips, which dissolve in the skin to release it.
Mailed and self-administered
“We are working on a seasonal vaccine against COVID-19 and combined influenza, which will be mailed directly to patients for them to administer themselves,” CEO Michael Schrader told AFP. .
The COVID-19 vaccine used will be that of the company Medigen, authorized in Taiwan.
Vaxess has just opened a factory near Boston, with funding from the US National Institute of Infectious Diseases (NIAID). The goal: to produce enough transdermal patches to vaccinate 2,000 to 3,000 people in clinical trials, to be launched next summer.
Because production capacity remains the real obstacle to the advent of this technology, which could be used for many other vaccines or drugs.
“This is the future”
“If you want to launch a vaccine, you have to produce hundreds of millions. And we don’t have that scale today. Nobody has it, ”explained Schrader who predicts the first products to hit the market in the next three years.
But the urgency of the pandemic has given a boost, he says, by attracting investors.
“From my point of view, it’s the future, it’s inevitable,” insists the boss. “In the next ten years, we will see a radical overhaul of the means of distributing vaccines around the world. ”