Results from a recent “challenge” trial led by researchers at Cincinnati Children’s reveal that an investigational norovirus vaccine appears well tolerated and effective against the most common strain of the virus.

The study involved 98 people who drank water dosed with norovirus, 50 of whom received the injected vaccine while 48 received placebo injections, The researchers, led by David Bernstein, MD, MA, presented their findings during IDWeek 2013™, a major infectious disease conference held in October. 

Among those who received the vaccine, 26 people were infected, the researchers said. In the other group, 29 people were infected. However, only 10 people who were vaccinated went on to develop mild, moderate or severe vomiting and/or diarrhea, compared with 20 people in the placebo group. This means the vaccine achieved a 52 percent efficacy in preventing disease.  It was even more effective in preventing severe disease.

Norovirus is a highly contagious cause of gastrointestinal illness, known for triggering outbreaks in cruise ships, military barracks, childcare centers and other places where people spend time in close quarters. Elderly people in long-term care facilities are especially vulnerable to norovirus.

The challenge trial involved volunteers who agreed to spend five days in a controlled, hospital-like setting. The next step will be to test the vaccine in a larger clinical trial under real-world conditions.

“Norovirus is very common. Worldwide, it causes about 200,000 deaths a year,” Bernstein says. “Ideally, we would like a vaccine to do a little better than 50 percent symptom reduction, but a vaccine that reduces severe symptoms could save many lives and help keep many more people out of the hospital, which could significantly reduce costs.”

Article by Tim Bonfield, Cincinnati Children’s. Contact: