Scientist at the Institut Pasteur- TheraVectys Joint Laboratory have demonstrated the efficacy of their lentiviral candidate vaccine “Lenti-COVID”, administered as an intranasal booster dose six months after primary vaccination with a messenger RNA vaccine, in a pre-clinical model. This intranasal booster induces protective immunity in the respiratory mucosa. These results pave the way for innovative vaccine strategy to reduce the viral transmission chain. The study is published in the journal Molecular Therapy. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9044714/
Scientist at the Institut Pasteur- TheraVectys Joint Laboratory have compared the immune responses of mice following a booster vaccination with either the candidate vaccine Lenti-COVID via nasal route or a third dose of messenger RNA vaccine via muscle route.
In both cases, IgG antibody responses in the blood were amplified. However, only Lenti-COVID administered intranasally, induced major players of mucosal immunity in the airways : (i) mucosal anti-Spike igA, and (ii) lung resident memory B cells, able to locally produce antibodies, and (iii) lung resident memory T cells, able to kill infected cells.
Induction of these major players of mucosal immunity by the Lenti-COVID vaccine candidate leads to complete pulmonary protection against the Delta and the Omicron variants of SARS-CoV-2, demonstrating the suitability of the Lenti-COVID vaccine candidate as an intranasal booster against COVID-19.
As the COVID-19 pandemic continues and the adaptive immunity initially induced by the currents COVID vaccines need to be reinforced, the development of a vaccine that would block the transmission of the virus in the long term and maintain this capacity against various emerging variants appears relevant, even if the SARS-CoV-2 virus become endemic.
Following this work, a clinical phase will have to be initiated to confirm the safety and the effectiveness of this approach in humans.
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Vesin, B*, Lopez, J*, Noirat, A*, Authié, P*, Fert, I., Le Chevalier, F., Moncoq, F., Nemirov, K., Catherine, B, Planchais, C., Mouquet, H., Guinet, F., Hardy, D., Langa-Vives, F., Gerke, C., Anna, F., Bourgine, M., Majlessi, L.**and Pierre Charneau** (2022). An intranasal lentiviral booster reinforces the waning mRNA vaccine-induced SARS-CoV-2 2 immunity that it targets to lung mucosa. Mol. Ther. *Equal contribution, **Senior authors. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9044714/