Nasal vaccines may serve better as a COVID-19 booster than current shots because they offer protection in the mucosal linings of the airway, where the coronavirus first lands, The New York Times reported Feb. 2.
Injected vaccines produce antibodies in the blood, few of which make it to the nose — the virus's entryway. This, in part, is why so many people who received their booster dose became infected amid the highly-transmissible omicron surge.
Instead, some experts' thoughts behind why mucosal vaccines may be ideal as boosters is because they coat the airways with long-lasting antibodies, and thus are better at preventing infection altogether, not just protecting from severe illness.
"It is the difference between planting sentries at the gates to bar intruders and trying to oust them after they had already stormed the castle," writes author Apoorva Mandavilli.
An immunologist at the University of Toronto, Jennifer Gommerman, PhD, told the Times nasal vaccines are "the only way to really circumvent person-to-person transmission," adding, "We can't live forever sheltering vulnerable people and boosting them so that their antibody levels stay artificially high."
The news outlet also cited a preprint study that found a nasal vaccine administered as a booster triggered immune memory cells and antibodies in the nose and throat and ramped up protection from initial vaccination.
"Our approach is to not use a nasal vaccine as a primary vaccination, but to boost with nasal vaccine, because then you can leverage the existing immunity that's already created," said Akiko Iwasaki, PhD, an immunologist at New Haven, Conn.-based Yale University who led the study.
An additional benefit to nasal vaccines is they would streamline the process of immunizing large populations, as they are less time-consuming and require less skill to administer, experts told the Times.
Currently there are at least a dozen nasal COVID-19 vaccines in development globally.
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