More than 6.3 million people have died during the COVID-19 pandemic, and respiratory infections remain a significant cause of illness and death worldwide, requiring an urgent global effort to develop vaccines that can be administered directly to the mucosa of the respiratory tract. Nasal spray flu vaccines are already known to be very effective in children, but much less effective in adults, leaving injectable flu vaccines as the first-line option for seasonal flu vaccinations.
The immune response is stronger when the vaccine is delivered deep into the lungs
The study: lead author Michael D’Agostino and his team worked here on mouse models of tuberculosis, which therefore develop stronger immune responses, with a vaccine administered directly into the lungs: “Upper respiratory tract infections tend to be benign. In the context of infections caused by viruses like influenza or SARS-CoV-2, the virus penetrates deeper into the lungs,” also explains Matthew Miller, co-author and viral pandemic expert at McMaster University.
A matter of fabric: scientists show that the immune response is much stronger when the vaccine is diffused deep into the lungs than when it is “deposited” in the nose and throat, this in particular due to the anatomy and nature of the tissue and immune cells available for response.
The study thus provides the first solid preclinical evidence supporting the development of inhaled vaccines rather than in the form of spray nasal for human vaccination against respiratory infections, including tuberculosis, COVID-19 and influenza.
And for COVID-19? McMaster scientists had previously shown that in addition to being needle-free and painless, an inhaled vaccine is highly effective in targeting the lungs and upper respiratory tract and can induce maximum protection with a much larger dose. lower than injected vaccines. The team has already developed a unique inhaled form of COVID vaccine, and argue that this deep delivery method offers the best defense against current and future pandemics.
A phase 1 clinical trial is underway to evaluate the inhaled aerosol vaccine in healthy adults who have previously received 2 or 3 doses of an injected COVID mRNA vaccine.