A nasal spray coronavirus vaccine booster helps protect mice from SARS-CoV-2. In this electron microscopy image, viral particles are shown as blue circles. Credit: CDC/ Hannah A Bullock; Azaibi Tamin |
A new coronavirus vaccine guards one body part especially vulnerable to infection: the nose.
Dosing mice with a nasal spray booster recruited an army of immune defenders to both the nasal cavity, where coronaviruses typically enter the body, and the lungs, scientists report in a preprint posted on bioRxiv.org.
Made only of coronavirus spike protein, the vaccine is part of a one-two punch that could one day protect people from infection. Dubbed “Prime and Spike,” the strategy relies on an mRNA coronavirus vaccine injection that primes the immune system to recognize SARS-CoV-2, followed by a nasal spray vaccine that shores up defenses at the mucus membranes.
Such a strategy might offer a way to counter the waning effectiveness of current mRNA coronavirus vaccines, says study author Akiko Iwasaki, a Howard Hughes Medical Institute Investigator at Yale University.
Until now, scientists had not tested nasal vaccines on animals that already had some pre-existing immunity, says Jacco Boon, a virologist at Washington University School of Medicine in St. Louis who was not involved with the new work. “This paper is telling us that the intranasal booster induces a really good immune response in the nose and the lungs,” he says. “It’s a clever strategy, and I hope they test it in people.”