Doctors have initiated trials for the world’s first vaccine targeting norovirus, a virus notorious for causing severe vomiting and diarrhea. The hope is that this vaccine could offer significant health and economic advantages, especially considering how quickly norovirus can spread among individuals in close proximity. Outbreaks are particularly common in settings like hospitals, care homes, schools, and nurseries.
While most individuals recover within a couple of days, norovirus can be particularly dangerous for children, the elderly, or those with weakened immune systems. Dr. Patrick Moore, a general practitioner and the national chief investigator for the trial in the UK, pointed out that there are currently no approved vaccines for norovirus globally. Instead, patients experiencing severe illness are often treated with intravenous fluids.
“The impact of norovirus is substantial,” said Dr. Moore. “It is responsible for approximately 685 million cases and 200,000 deaths worldwide each year, with around 4 million cases and 12,000 hospitalizations occurring annually in the UK alone.” He emphasized that in the UK, norovirus incurs costs of about £100 million for the National Health Service, with lost earnings pushing that figure to around £300 million.
The phase 3 clinical trial, named Nova 301, is set to run for two years and will enroll 25,000 adults primarily over 60 years old from countries including Japan, Canada, and Australia. A total of 27 NHS primary and secondary care sites across England, Scotland, and Wales are participating, with 2,500 participants expected to be recruited starting in late October. Mobile units will be utilized to facilitate participation.
This UK trial is part of a broader 10-year partnership between Moderna and the UK, involving collaboration with the National Institute for Health and Care Research, the Department of Health and Social Care, the UK Health Security Agency, and Moderna, the vaccine’s manufacturer. During the trial, participants will be randomly divided into two groups: one receiving the new vaccine and the other receiving a saline placebo.
The norovirus vaccine employs mRNA technology, similar to the approach used by Pfizer/BioNTech and Moderna in creating their Covid-19 vaccines. This technology works by introducing a strand of mRNA into human cells, which instructs the cells to produce proteins associated with the virus. These proteins then stimulate the immune system, offering protection against future infections.
For this new vaccine, the mRNA provides instructions for producing the protein coat of three different types of norovirus, resulting in the creation of harmless virus-like particles that trigger antibody production. While earlier trials have indicated that the vaccine generates a strong immune response in humans, the current trial aims to determine its efficacy against the virus and the duration of its protective effects.
“We consider at least 65% efficacy or higher to be clinically meaningful,” stated Dr. Doran Fink from Moderna. If successful, the company plans to submit a marketing application to regulatory bodies by 2026, with a review process likely to take up to a year. Additional trials in teenagers and younger children would follow.
Professor Saul Faust from the University of Southampton and co-clinical lead for the NIHR Vaccination Innovation Pathway added that a successful vaccine could help ensure that care homes operate normally, allowing families to visit loved ones. Dr. Moore stressed the importance of the trial, indicating its potential to prevent frail individuals from declining further. “We wouldn’t be moving at this pace with the trial if it wasn’t going to benefit individuals directly,” Faust remarked.
