Nasal COVID-19 Vaccine may Fight Against New Variants

Intranasal COVID-19 vaccination provides broad-based protection against heterologous respiratory viruses in mice found new study published in the journal Science Immunology.

The emergence of variants such as delta and omicron have sent scientists scrambling to determine whether existing vaccinations and boosters are still effective against COVID-19.

‘Both COVID-19 vaccine injections and nasal vaccines increased levels of antibodies in the blood of mice, but the nasal vaccine only enabled antibody production in the respiratory epithelium.’

A new response to the rapidly mutating virus might be found right at the door to our lungs, says Yale's Akiko Iwasaki, the Waldemar Von Zedtwitz Professor of Immunobiology.

Mucous membranes contain their immune defense system that combat air- or foodborne pathogens. When challenged, these barrier tissues produce 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 combatting intestinal pathogens, researchers wondered if triggering IgA response might also produce a localized immune response against respiratory viruses such as COVID-19.

To know this, researchers 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 which had received vaccine intranasally were much better protected against respiratory influenza than those that received injections.

Nasal vaccines 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 research team is currently testing nasal vaccine strains against COVID strains in animal models.

If the nasal vaccines prove to be safe and efficient in humans, they can be used in conjunction with current vaccines and boosters that work system-wide to add immune system reinforcements at the source of infection.



Source: Medindia