A new study by Yale's Akiko Iwasaki, the Waldemar Von Zedtwitz Professor of Immunobiology, has found that nasal vaccines may help in the fight against new COVID-19 variants. As per findings of the new research, published in the Science Immunology Journal, intranasal vaccination provided broad-based protection against heterologous respiratory viruses in mice.
"The best immune defence happens at the gate, guarding against viruses trying to enter. Mucous membranes contain their own immune defence system that combat air or foodborne pathogens. When challenged, these barrier tissues produce B cells which in turn secrete immunoglobin A (IgA) antibodies. Unlike vaccines which elicit a system-wide immune response, IgA antibodies work locally on mucosal surfaces found in the nose, stomach, and lungs," senior author of the study, Iwasaki was quoted as saying by ANI.
"While both vaccine injections and nasal vaccines increased levels of antibodies in the blood of mice, only the nasal vaccine enabled IgA secretion into the lungs, where respiratory viruses need to lodge to infect the host," Iwasaki added.
Last month, addressing Republic's ‘India Economic Summit 2021’, Bharat Biotech's managing director, Krishna Ella, informed the country about its upcoming nasal vaccination to fight COVID-19
"We have completed the Phase 2 trial for the nasal vaccine. We have picked up science; even the Western world has not been able to pick up. It will stop the transmission of the virus," he said at the Summit
Most viruses, including those associated with SARS-CoV-2, that causes COVID-19, enter through the mucosa (moist tissue present in nose and mouth) and infect cells and molecules present in the mucosal membranes.
Intramuscular vaccines fail to trigger an immune response from the mucosa and depend on immune cells from other parts of the body and are therefore not as effective as nasal vaccines, which interacts with the T-Cell that exists in the nose and the throat and targets the immune cells present in the mucosal membrane, besides, triggering immune cells in other parts of the body. Nasal vaccines are also easier to administer in comparison to intramuscular vaccines.
While the nasal vaccine is still in its trial phase, India is carrying out its nationwide immunisation drive with two intramuscular vaccines- Covaxin, manufactured by Bharat Biotech, and Covishield, manufactured by the Serum Institute of India (SII).
Apart from Covishield and Covaxin, the Drugs Controller General of India has approved Sputnik V, Moderna, and Johnson & Johnson, and Zydus Cadila's COVID-19 vaccines.