A new intranasal vaccine may provide broad-based protection against COVID 19.
In a new study by Yale’s Akiko Iwasaki, it was found that intranasal vaccination provided broad-based protection against heterologous respiratory viruses in mice.
Their findings were published in the December 10 issue of `Journal Science Immunology’.
“The best immune defense happens at the gate, guarding against viruses trying to enter,” said Akiko Iwasaki, senior author of the study
The study said mucous membranes contain their own immune defense system that combat air- or food-borne 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. While the protective role of IgA-producing cells had been well established in combating intestinal pathogens, Iwasaki’s lab wondered if triggering IgA response might also produce a localized immune response against respiratory viruses,” the study said.
Working with researchers at Icahn School of Medicine at Mount Sinai in New York, they tested a protein-based vaccine designed to jump-start an IgA immune response, administering it to mice through injections, as is commonly done with systemic immunizations, and also intranasally. They then exposed mice to multiple strains of influenza viruses. They found that mice that had received vaccine intranasally were much better protected against respiratory influenza than those that received injections. Nasal vaccines, but not the shot, also induced antibodies that protected the animals against a variety of flu strains, not just against the strain the vaccine was meant to protect against.
The Yale team is currently testing nasal vaccine strains against COVID strains in animal models.
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 said.