In a new study, researchers have developed a vaccine that targets the COVID-19 virus, can be given in one dose via the nose and may help prevent infection caused by the novel coronavirus.
The research was conducted by scientists at Washington University School of Medicine in St. Louis.
Unlike other COVID-19 vaccines in development, this one is delivered via the nose, often the initial site of infection.
In the new study, the researchers found that the nasal delivery route created a strong immune response throughout the body, but it was particularly effective in the nose and respiratory tract, preventing the infection from taking hold in the body.
To develop the vaccine, the researchers inserted the virus’ spike protein, which coronavirus uses to invade cells, inside another virus—called an adenovirus—that causes the common cold.
But the scientists tweaked the adenovirus, rendering it unable to cause illness.
The harmless adenovirus carries the spike protein into the nose, enabling the body to mount an immune defense against the SARS-CoV-2 virus without becoming sick.
In another innovation beyond nasal delivery, the new vaccine incorporates two mutations into the spike protein that stabilize it in a specific shape that is most conducive to forming antibodies against it.
The team was happily surprised to see a strong immune response in the cells of the inner lining of the nose and upper airway—and profound protection from infection with this virus.
These mice were well protected from disease. And in some of the mice, the team saw evidence of sterilizing immunity, where there is no sign of infection whatsoever after the mouse is challenged with the virus.
The team says adenoviruses are the basis for many investigational vaccines for COVID-19 and other infectious diseases, such as Ebola virus and tuberculosis, and they have good safety and efficacy records, but not much research has been done with nasal delivery of these vaccines.
All of the other adenovirus vaccines in development for COVID-19 are delivered by injection into the arm or thigh muscle. The nose is a novel route, so the results are surprising and promising. It’s also important that a single dose produced such a robust immune response. Vaccines that require two doses for full protection are less effective because some people, for various reasons, never receive the second dose.
One author of the study is Michael S. Diamond, MD, Ph.D.
The study is published in Cell.
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