A way has been opened to prevent the deadly foodborne illness caused by norovirus with medication. Each year, 700 million people worldwide are infected with norovirus, resulting in 200,000 deaths, but there is still no vaccine available for prevention.
Researchers from the U.S. biotechnology company Vaxart and the University of Texas at Austin announced on the 6th in the international journal 'Science Translational Medicine' their findings on an oral vaccine and antibody that can prevent norovirus infection.
The Vaxart research team developed an oral vaccine called 'VXA-G1.1-NN' by inserting the gene that makes the protein shell of the most common GI.1 genotype norovirus into a harmless adenovirus vector. When taken, the vaccine releases the norovirus gene in the small intestine, producing antigen proteins and triggering an immune response that generates antibodies.
The researchers conducted Phase 1 clinical trials with 65 adults aged 55 to 80. They divided the doses into low, medium, and high doses, administering two doses at intervals of 28 days each to confirm whether antibodies were produced. As a result, participants who completed the two doses had antibodies generated for up to 210 days, showing immunity. Participants receiving the high-dose vaccine showed a 6.9-fold increase in antibody production in saliva and a 9.3-fold increase in the nasal cavity compared to those receiving the low dose.
Some side effects were observed due to the vaccine, but most were mild. The Vaxart researchers noted, 'We have confirmed the possibility of preventing norovirus infection with an oral vaccine,' adding that 'it is expected to be effective against most variants with just one genotype, GI.1.'
Norovirus causes infectious gastroenteritis in humans through food. It survives even at a low temperature of minus 20 degrees Celsius and is considered a major cause of winter foodborne illnesses. South Korea also recorded the highest number of infections in the past 10 years last month, making it a serious social issue.
The University of Texas researchers discovered the structure and mechanism of action of the antibodies induced by Vaxart's vaccine. This research was primarily conducted by postdoctoral researcher Park Joo-yeon, Lisa C. Lindesmith from the University of North Carolina at Chapel Hill, and Adam S. Olia from the National Institutes of Health (NIH).
The researchers administered Vaxart's vaccine to two individuals who had prior experience with norovirus infection and identified a monoclonal antibody 'VX22' that targets norovirus. While participants already had some antibodies, the expression of VX22 significantly increased following the vaccination.
The VX22 antibody was found to be effective against seven genotypes including 'GII.4', which had previously caused an outbreak, as well as GII.2, GII.3, GII.6, GII.12, GII.14, and GII.17. The difficulty in developing a norovirus vaccine so far has been attributed to the existence of 48 different genotypes and the periodic emergence of different strains each year.
Finding antibodies effective against multiple genotypes of norovirus is expected to aid in future vaccine development. Park Joo-yeon stated, 'The key to this study was confirming that the human immune system can produce antibodies capable of broadly neutralizing various rapidly evolving norovirus variants simultaneously,' adding that 'we can also utilize the location of the norovirus antigens that VX22 targets for future vaccine development.'
Of course, these results are based on Phase 1 clinical trials, and it is still too early to say whether commercialization will be successful. To commercialize the vaccine, it must go through Phase 3 clinical trials. Moderna, which developed the COVID-19 vaccine, also pursued a norovirus vaccine and reached Phase 3 trials but failed.
Moderna conducted Phase 3 clinical trials for a norovirus vaccine made with messenger ribonucleic acid (mRNA), similar to the COVID vaccine, but halted the trials last month after the emergence of side effects including neurological inflammation known as Guillain-Barré syndrome.
References
Science Translational Medicine (2025), DOI: https://doi.org/10.1126/scitranslmed.ads0556
Science Translational Medicine (2025), DOI: https://doi.org/10.1126/scitranslmed.ads8214