This vaccine was first tested in vivo in a pre-clinical mouse model. Two nasal applications, three weeks apart, induced a strong humoral immune response – in particular of the mucosal compartment with neutralising Immunoglobulin A (IgAs), which are polyspecific, i.e. more permissive against variation of the Sars-CoV-2 – along with a cellular response in the nasal cavities and lungs. The protective efficacy of the vaccine was also assessed in terms of survival and absence of clinical signs after infection on vaccinated animals, 100% of individuals survived with no clinical signs (respiratory distress, weight loss, etc.) unlike the unvaccinated control group. Second, the candidate vaccine was tested for contagiousness in the established Syrian hamster model, which mimics the human pathophysiology of COVID-19, again providing striking results with no viral detection in the lungs and nose of vaccinated/infected animals while unvaccinated/infected animals showed a high levels of viral RNA in both lungs and nasal cavities. These results, highly predictive of the effectiveness of a vaccine in humans, allow us to predict that contagiousness between individuals is completely abolished.
An easily administered, non-invasive, vaccine as a first dose or a booster
Technically, the vaccine will be administered by means of a small adapter placed at the end of a needle-less syringe, allowing an ideal diffusion within the nasal cavity. Currently, a device developed for this vaccine specifically for humans is being evaluated in collaboration with the Recipharm/Resyca group. Non-invasive and with minimal logistics requirement, this basic vaccination system would allow for a wider distribution to Europe and far beyond. Moreover, the vaccine is highly stable at room temperature and even longer at 4°C and thus would not imply the required restraining logistics mandatory to maintain cold chain integrity, unavailable in most countries of the world.
This vaccine would therefore target unvaccinated populations to protect against severe and moderate forms of COVID-19 and could moreover be a booster for already vaccinated populations to prevent transmission of the virus.