Nasal Vaccines May Induce Better Protection From Viruses

Compelling new preclinical research led by scientists from Yale University has found intranasal vaccination may be much more effective at generating immunity against a number of respiratory viruses compared to more conventional injection-delivered vaccination, Rich Haridy reported for New Atlas.

Photo Insert: The new study promisingly reveals nasal vaccines not only induce effective IgA responses but may promote broad immunity against more than just the single viral strain in a vaccine.

The COVID-19 pandemic has rekindled great interest in delivering vaccines via inhalable nasal spray. Not only is this kind of vaccine delivery system much easier to administer but for several years researchers have hypothesized it to be potentially more effective against infections that initially take hold in the upper respiratory tract.

"The best immune defense happens at the gate, guarding against viruses trying to enter,” explains senior author on the new study, Akiko Iwasaki. The new research was published in the journal Science Immunology.

Immunoglobulin A (IgA) antibodies are one of the immune system’s frontline soldiers. These antibodies are primarily secreted by mucosal surfaces in the body, mostly seen in the nose, gut and lungs.

The idea behind a nasal vaccine is that it could directly train mucous membranes in the nose how to target certain airborne pathogens so an immune response can be mounted as soon as a virus enters a human body.

This new study promisingly reveals nasal vaccines not only induce effective IgA responses but may promote broad immunity against more than just the single viral strain in a vaccine.

The study reports on a series of mouse experiments comparing the effects of an influenza vaccine delivered intranasally and more traditionally via injection. The researchers exposed the mice to a number of different influenza strains beyond the one the vaccine was designed to target.

The findings revealed the animals receiving the nasal vaccine were much better protected from a broad variety of influenza strains compared to the mice receiving injections.

Focusing on IgA responses the researchers discovered not only did the nasal vaccine induce IgA responses in nasal mucous membranes, but significant levels of IgA secretion were detected in the lungs as well.

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