To date, there are no approved vaccines or antiviral treatments for human norovirus, the leading cause of acute gastroenteritis outbreaks worldwide with more than 685 million infections each year. Norovirus is highly contagious and symptoms can include nausea, vomiting, watery diarrhea, fever, stomach pains, headache, and muscle aches.
New collaborative research between Griffith University and Australian biotechnology company Marinova, investigated whether compounds from a range of brown and green seaweeds could block the illness in the early stages of infection. The findings are published in the journal Microbiology Spectrum.
Senior author Dr. Grant Hansman from Griffith’s Institute for Biomedicine and Glycomics said noroviruses infect people by attaching to molecules in the intestine called histo-blood group antigens (HBGAs).
“We tested the seaweed compounds fucoidan and ulvan to see how well they prevented norovirus virus-like particles from binding to human saliva samples which contain HBGAs,” Dr. Hansman said. “Fucoidan, from brown seaweed, showed the strongest and most consistent blocking activity against two major norovirus strains, GII.4 and GII.17.”
The fucoidan likely bound to the HBGA binding pocket to form a physical shield, making it harder for the virus to attach.
Co-senior author Associate Professor Thomas Haselhorst said fucoidan had a history of dietary use and had demonstrated good tolerability in human studies, with fucoidan used in premium dietary supplements. “Our study highlights that fucoidan could be a promising, natural treatment for preventing norovirus infection,” he said.
Research is now focused on validating how fucoidan could be formulated to maximize its protective effect in the gastrointestinal tract.
More information
Barbara C. Wimmer et al, Harnessing marine sulfated polysaccharides to inhibit norovirus: from seaweed to solution, Microbiology Spectrum (2026). DOI: 10.1128/spectrum.02445-25
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