Inhaled Vaccines Provide Better Protection Than Nasal Sprays, Explain Scientists
Scientists at McMaster University have conducted a comparison of respiratory vaccine delivery systems and confirmed that inhaled aerosol vaccines provide greater protection and immunity than nasal sprays.
Nasal sprays primarily reach the nose and throat, while inhaled aerosols bypass the nasal passage and deliver vaccine droplets deep into the airways to elicit a broad protective immune response.
The study, published in the online journal Frontiers in Immunology, used a tuberculosis vaccine to compare delivery methods to measure immune response distribution, droplet distribution and efficacy in animals.
When the vaccine was administered directly into the lungs, it elicited a stronger immune response, providing significantly better protection against tuberculosis.
Clinically, upper respiratory tract infections are usually not severe. When infections are caused by viruses that cause SARS-CoV-2 or influenza, they are usually severe when the virus penetrates deep into the lungs and makes a person very sick.
Importantly, the immune response triggered when the vaccine is administered deep into the lungs is much stronger than when it is deposited in the nose and throat because of the anatomy and nature of the tissue, and the immune cells available to respond are very different, explained one of the researchers behind the study.
According to this study, for the first time, there is strong preclinical evidence to support the development of an inhaled aerosol nasal spray for vaccinating people against respiratory infections such as COVID-19, tuberculosis and influenza.
COVID-19 killed more than 6.3 million people, and respiratory infections remain a leading cause of illness and death around the world. Therefore, new efforts are urgently underway worldwide to develop vaccines that can be administered through the mucous membranes of the respiratory tract.
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