Researchers from the Washington University School of Medicine in St. Louis have developed a nasal vaccine against the SARS-CoV-2 virus that effectively protects susceptible mice from developing symptoms after receiving a single dose.
Given that infection often takes place via the nose, the vaccine was designed to be delivered intranasally. “We were happily surprised to see a strong immune response in the cells of the inner lining of the nose and upper airway — and a profound protection from infection with this virus,” said senior author Michael S. Diamond, MD, PhD.
The mice used in the study were found to be well protected from the disease, and some even exhibited sterilizing immunity, i.e., showing no sign of infection whatsoever after being exposed to the virus.
According to the authors, the vaccine works by delivering the virus’ spike protein (used to invade cells) inside a deactivated adenovirus – a type of virus that causes the common cold – which allows the body to mount an immune defense against SARS-CoV-2 without becoming sick.
In addition, the spike protein used in the vaccine contains two engineered mutations that make it “freeze” into a specific shape which makes it easier for the immune system to generate antibodies against it.
For comparison, the new vaccine was delivered to the mice in two ways – via the nose and through intramuscular injection. While the latter method of delivery did prevent pneumonia, administering the vaccine intranasally also prevented infection in the nose and lungs.
This means that individuals given the vaccine via the nose would not spread the virus to others, thereby curbing the ongoing pandemic, and would not develop infections elsewhere in the body.
The research team is currently preparing for a new bout of research in non-human primates, and plans to commence human clinical trials as soon as possible, without violating the proper evaluation pipelines.
“We’re looking forward to beginning the next round of studies and ultimately testing it in people to see if we can induce the type of protective immunity that we think not only will prevent infection but also curb pandemic transmission of this virus,” Diamond said.