Scientists have developed vaccines to offer protection against new COVID-19 variants throughout the pandemic. The majority are mRNA vaccines, in which mRNA’s are introduced to our body for cells to make spike protein antigens that can be used to create antibodies. This allows the body to recognize the spike protein on SARS-CoV-2 upon infection.
Neutralizing the virus upon entry into the respiratory system remains critical with the arrival of more transmissible and elusive Omicron sub-variants. If an infection is not prevented, the progression of symptoms means the patient can spread COVID-19 more rapidly and develop complications like long COVID. Therefore, immunity needs to arise in the mucosal membranes as soon as possible. Our nasal airways and respiratory tracts are wet mucosal surfaces that act as the first line of defense against pathogens. According to Jie Sun, Professor of Medicine at the University of Virginia, our bloodstreams experience an uptick in immune activity from the mRNA vaccine, while the mucosal linings undergo minimal antibody neutralizing functionality following vaccine administration. Dr. Sun’s lab data shows that mRNA vaccines did not activate “tissue-residing cellular immunity” in the airways, thus allowing the Omicron variant to circumvent mucosal antibody neutralization.
COVID-19 Variant Evolution
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Recently, a Cornell research team conducted a study to determine the efficacy of nasal vaccines. A COVID-19 infection starts with the virus manipulating cellular proteins like the TMPRSS2 to gain entry. To inhibit TMPRSS2’s interaction with the virus, researchers found N-0385, a compound that halts infection. Then, they used a nasal spray with N-03085 in COVID-19 positive mice as the experimental group and a nasal saline dose in COVID-19 positive mice as the control group. After administering daily doses for a week, 70% of the mice in the experimental group survived with healthy lungs. In another trial of four days, all N-0385 sprayed mice survived while 80% of the saline group perished. Dr. Sun comments that the nasal vaccine grants higher immunity by antigen-boosting the T and B cells of the immune system. From the promising results, nasal sprays appear quick and effective, qualifying them as a potential addition to the medical arsenal for the fight against COVID-19.
Nasal Spray Administration
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With nasal spray’s ability to generate bolstered immune responses, human clinical trials are underway to ensure the right dosage of the spray as well as the consideration for side effects. Akiko Iwasaki, an immunology researcher at the Yale School of Medicine, describes the benefits of a nasal vaccine. Spraying a recombinant spike protein into the nose after someone receives an mRNA vaccination converts the vaccine immunity into mucosal immunity. This “prime and spike” approach joins forces with memory T cells to activate antigen-presenting cells in the mucosal membranes. Truly, nasal sprays possess the power to fortify our immune system and are becoming accessible to the public. Hopefully, they can flatten the curve once and for all.
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