According to a recent paper in Biology Methods and Protocols, published by Oxford University Press, researchers studying SARS-CoV-2 may have developed new methods to administer vaccines orally, which would be both easier to administer and more effective at combatting illnesses.
The best way to neutralize viruses is before they can enter inside human cells but are only on the external surface of epithelial cells that line and produce mucus in the lungs, nose, and mouth. A specific class of antibodies known as Immunoglobulin A operates in mucus and can disable viruses. However, the production of specific immunoglobulins/antibodies for a given virus has to be first induced by a vaccination. Vaccination that effectively produces Immunoglobulin A antibodies rapidly would better prevent disease.
Since the coronavirus, like influenza, infects bronchial cells, researchers believe it is important to induce the secretion of virus antigen-specific Immunoglobulin A in the mucosa rather than in the blood. Recently, scientists have developed vaccines administered via alternative routes, such as nasal or oral.
Such vaccines are more effective in inducing Immunoglobulins A than those administered by conventional subcutaneous vaccinations. Although doctors have used nasal vaccines in clinics, they have found that these vaccines tend to produce side effects, such as headaches and fever, on the central nervous system or lungs.
This study examined a new vaccination against SARS-CoV-2 designed to induce the production of Immunoglobulin A orally (under the tongue) in monkeys. The method worked and animals used for the test produced the necessary antibodies against the disease without discernable side effects. This suggests that, with further research, clinics may soon be able to offer oral vaccines against the coronavirus, which would be more popular and more successful against the disease.
Reference: “SARS-CoV-2 sublingual vaccine with RBD antigen and poly(I:C) adjuvant: Preclinical study in cynomolgus macaques” by Tetsuro Yamamoto, Masanori Tanji, Fusako Mitsunaga and Shin Nakamura, 13 September 2023, Biology Methods and Protocols.