Norovirus vaccine shows promise in mice

An experimental vaccine to fight the human norovirus, which causes close to 90 percent of highly contagious nonbacterial illnesses that lead to vomiting and diarrhea, has been found to provoke a strong immune response in mice.

Ohio State University scientists used a novel viral vector-based method to develop the vaccine, which led to a high level of antibodies, additional immune response in the gastrointestinal system and a robust white blood cell response without causing harm to the mice.

"The mice in our study developed a much higher antibody response to our vaccine candidate than they did to a more traditional vaccine," Jianrong Li, an assistant professor of food science and technology at Ohio State and the senior author of the study, said. "That's one of the keys, to have a sustained antibody response, so that when the disease comes along, you can neutralize the virus and protect yourself."

According to the Centers for Disease Control and Prevention, there are more than 21 million estimated cases of acute gastroenteritis each year that are caused by norovirus infection. The virus is so contagious that as few as 10 viral particles may cause infection. There is currently no antiviral drug or vaccine available for human norovirus.

The researchers inserted a human norovirus capsid cell - a cell from the virus’s outer shell - on the genome of a different virus, creating a recombinant virus. The recombinant viral vector was then injected into the mice, triggering an immune response to the norovirus as a result of the capsid cell.

"So it looks like the virus and acts like the virus, but it's not, and that is how a vaccine designed with virus-like particles should function," Li said. "The virus-like particles can be continually produced in animals or humans for several weeks and stimulate strong immune responses. That's the advantage of using VSV."

Two weeks after receiving the vaccine, the mice had around 25 times higher levels of antibodies than those induced with a traditionally prepared vaccine.