Coronavirus vaccine shows promising immune response in animals, University of Washington researchers say

Researchers with the University of Washington's Department of Microbiology say a coronavirus vaccine they are developing has generated protective antibodies in mice and non-human primates with just one injection.

The design of this vaccine, the researchers say, may also facilitate scalable production to avoid bottlenecks in getting onto the market.

"Our vaccine was able to meet key requirements for an effective pandemic vaccine," said Dr. Deborah Fuller, one of the scientists leading the effort on Monday. "It was able to induce immunity quickly, it was able to induce T cell responses, and it contributes to protection from disease."

Fuller said that a type of white blood cell known as T cells have responded favorably to the vaccine, providing a second line of defense against Covid-19 — that's in addition to antibodies, blood proteins created by the immune system in response to the presence of a virus.

The vaccine is comprised of replicating RNA and a lipid based nanoparticle designed to stabilize and enhance its entry into cells.

"What this vaccine does is, once it gets in the cell ... it starts replicating itself, producing more copies of itself," Fuller said. "That will produce more vaccine protein and potentially make it more immunogenic."

Fuller said the vaccine triggered strong immune responses in aging animals, a crucial indicator of whether the vaccine might successfully immunize elderly humans. Older adults have been most vulnerable to severe cases of Covid-19 and tend to respond less effectively to vaccinations.

Fuller added that her lab will observe these animals for another four to six months, to make sure that the effects of the vaccine persist.

"We've seen promising results indicating that the antibody responses are not declining like you see typically, and have been reported in convalescent patients," she said. "Instead, the antibody appeared to go up and continue to be sustained."

The pharmaceutical company HDT Bio will advance the vaccine to human clinical trials, which University of Washington scientists say are expected to begin later this summer.