A new trial that aims to protect against norovirus, a highly contagious stomach bug that causes vomiting and diarrhoea, is set to be trialled on 25,000 people.
Norovirus, commonly referred to as the “winter vomiting bug”, affects people of all ages and has had significant societal and healthcare impacts.
In the past, it has led to the closure of hospital wards, school absences and lost workdays.
The trial, led by pharmaceutical company Moderna, will take place over the next two years in six countries, targeting adults primarily over the ages of 60.
If successful, the vaccine could reduce the number of vulnerable hospitalised during the winter months, easing pressure on the NHS, which spends an estimated £100 million annually on treating norovirus-related cases.
While vaccines against flu, COVID-19, and RSV (respiratory syncytial virus) are already widely used, this trial would mark a significant milestone as a the first licensed vaccine against norovirus.
The new vaccine, like Moderna’s COVID-19 shot, uses mRNA technology to teach the immune system how to recognise and defend against the virus by producing antibodies.
If the vaccine demonstrates at least 65 percent efficacy, and further trials confirm its effectiveness, it could potentially be extended to children.
However, this expansion is expected to be several years away.
Several other companies, including HilleVax and Vaxart, are also working on developing vaccines against norovirus.
Dr Patrick Moore, a GP from Dorset and the trial’s chief investigator, explained that norovirius is challenging to combat due to its shifting genetic diversity.
“There is a broad and shifting diversity of genotypes over time,” Dr. Moore said.
To address this, the vaccine is designed to target three of the most common strains to provide optimal protection.
The trial is a collaboration between the UK government, the National Institute for Health and Care Research (NIHR), and Moderna.
Researches will be monitoring trial participants, with half receiving the vaccine and the other half receiving a placebo.
The goal is to determine how long the vaccine offers protection, how effective it is, and how frequently it might need to be updated.
Side effects will also be monitored throughout the study. In the UK alone, norovirus infects nearly four million people every year, resulting in 12,000 hospitalisations and 80 deaths.
Those most at risk include older adults and care home residents, but the virus also commonly affects healthcare workers, childcare providers, and people in communal environments like cruise ships and schools.
Professor Saul Faust, a specialist in infectious diseases from the University of Southampton, warned: “Any infection increases frailty – and in the older population, it’s difficult to reverse that.”
The trial will utilise mobile units to administer the vaccine in care homes, reaching vulnerable populations who may benefit the most from protection.