Nasal vaccine might help fight new Covid-19 variants: Study

In a new study by Yale’s Akiko Iwasaki, the Waldemar Von Zedtwitz Professor of Immunobiology, it was found that intranasal vaccination provided broad-based protection against heterologous respiratory viruses in mice.

The research has been published in the ‘Science Immunology Journal’.

“The best immune defence happens at the gate, guarding against viruses trying to enter,” said Iwasaki, senior author of the study.

Mucous membranes contain their own immune defence 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 localised immune response against respiratory viruses.

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 intra-nasally.

They then exposed mice to multiple strains of influenza viruses. They found that mice that had received vaccine intra-nasally 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.