A vaccine for the world’s most common cause of acute gastroenteritis and the USA’s most common cause of foodborne illness is now in human clinical trials. The trial by Japan’s Takeda Pharmaceutical Co. Ltd. involves the first norovirus vaccine prospect to enter human adult or efficacy trials. Rob Goodwin, vice president and global norovirus program head for Takeda Vaccines, told Food Safety News a “period of years” could still remain before the norovirus vaccine is available. He says the Phase 2b, double-blind, randomized, placebo-controlled trials will involve healthy men and woman, ages 18-49, to assess efficacy and safety. “Winter vomiting disease,” as norovirus is sometimes caused, has been around since the 1920s. About 30 norovirus genotypes since then have spread around the world, including to many areas that do not have much in the way of winter. An estimated 200,000 deaths and 700 million illnesses are now annually blamed on norovirus worldwide. The diarrheal illness is a common cause of death for children, especially those under age 5 in developing countries. The human trials will allow the Japanese pharmaceutical firm to evaluate how well the intramuscular administration of Takeda’s norovirus vaccine works against moderate or severe acute gastroenteritis due to norovirus, a intestinal infection involving watery diarrhea, vomiting, abdominal cramps, nausea and sometimes fever, all of which can led to significant dehydration. Goodwin says vaccine developers are especially concerned about two groups that suffer the greatest illness burden, children under age 5 and seniors over age 65. He says the vaccine must have a clinical impact on the illnesses of the various age groups. A clinical impact would be eliminating the need for hospitalization, for example. The developers expect the norovirus vaccine will work more like the protection against rotovirus than a flu shot. Flu shots are prepared annually to combat new strains. Rotavirus vaccines have shown a broader span of effectives. Goodwin says Takeda has found its vaccine is effective for one year, and will now see if that stretches out further — to two years and then five and 10 years. Norovirus has emerged as the most common cause of acute gastroenteritis across all ages since the rotavirus vaccine, which hit the market in 1998, has shown success. Takeda, which claims to focus on “high unmet needs,” has done infectious disease work with such areas as dengue fever, polio, and foot and mouth disease. Its norovirus vaccine candidate contains virus-like particle antigens, which are proteins that mimic the outer surface of norovirus. “Together with our collaborators, Takeda has dedicated substantial scientific effort to understanding the best ways to prevent norovirus through vaccination, “Goodwin said. “This trial moves us one step closer to putting an important tool for prevention in the hands of individuals, families and public health systems around the globe.” The Public Library of Science (PLOS) has been monitoring the “prospects” for norovirus vaccine development since setting up a PLOS Collections website dedicated  to the subject last April.   San Francisco-based PLOS is an open source nonprofit. The Takeda vaccine is designed to cover the two norovirus genogroups that cause the majority of human illnesses. It is the only clinical-stage norovirus vaccine under investigation at the present time. (To sign up for a free subscription to Food Safety News, click here.)