World-first vaccine for norovirus sickness bug to be trialled in UK

Hospital admissions due to norovirus cost British taxpayers about £100 million a year

A person receiving a vaccination.

The world's first vaccine for the vomiting bug norovirus is set to be trialled in the UK in a move Health Secretary Wes Streeting said could cut the “burden on the NHS”.

Moderna's new mRNA vaccine will enter final stages of testing in the next two weeks, with results so far showing it creates a “strong immune response”.

Norovirus is linked to about 12,000 hospital admissions in the UK each year and experts believe the vaccine could stop people developing the vomiting and diarrhoea bug.

The shot uses mRNA technology to tell the immune system to recognise a “foreign” protein on viruses and mount an attack, in this case targeting three main strains.

Dr Patrick Moore, chief investigator of the study and National Institute for Health and Care Research (NIHR) director in the south-west, said there were currently “no approved vaccines for norovirus anywhere in the world” and the only treatment available for people with serious illness in hospital is intravenous fluids.

"Norovirus is what we know as the winter vomiting bug and it’s highly transmissible," he added. “It causes vomiting and diarrhoea, usually for two to three days. It can affect people of all ages and it usually peaks in the winter months in the UK … but we do see norovirus throughout the whole of the year.

“About one in five cases of gastroenteritis are caused by norovirus – that’s about four million cases annually in the UK and about 685 million globally.”

A total of 27 NHS hospitals and health centres in England, Scotland and Wales are taking part in the trial, with some running mobile clinics that could visit care homes or other community sites.

Overall, it is hoped 2,500 people in the UK will sign up for the trial before the end of December. Half will receive the vaccine, with the rest taking a "dummy" drug.

All participants will be followed up for about 25 months and experts hope the results will show 65 per cent or higher efficacy for the jab.

Moderna will also analyse whether it should be used as a seasonal shot like the flu vaccine, or if it could offer lifelong immunity.

The firm hopes to file marketing applications in 2026 to have the vaccine approved by health regulators.

“Norovirus is highly infectious and puts the NHS under huge strain every winter, costing taxpayers about £100 million ($130 million) a year," Mr Streeting said.

“The UK is leading the way to develop a world-first vaccine for this vomiting bug, starting with this innovative vaccine trial delivered through the government-funded National Institute for Health and Care Research.

“Not only is this a huge vote of confidence in the UK’s life sciences sector but a successful vaccine will help shift our health system away from sickness and towards prevention – reducing pressure on the NHS and keeping people well during the colder months.”

Researchers leading the trial said it would include adults of all ages, though people aged 60 and older are being encouraged to join, as they can be badly affected by norovirus.

If the vaccine works in adults, the trial is then likely to be extended to children.

The US, Canada and Japan are also taking part in the study, with a possible extension to Australia. Overall, about 25,000 people are expected to be recruited globally.

The vaccine has been engineered to combat three strains of the virus, which were responsible for more than two thirds (67 per cent) of noroviruses cases in 2023/24.

“We are delighted to bring this trial to the UK – by advancing our investigational mRNA norovirus vaccine into a pivotal phase 3 trial, we are one step closer to potentially providing a new tool to prevent infection from this highly contagious virus, which places a significant burden on health systems globally," said Dr Melanie Ivarsson, chief development officer at Moderna.

Dr Moore said older adults and immunocompromised patients are usually at higher risk of severe complications and even death from norovirus, with about 80 deaths per year in the UK among an estimated 200,000 worldwide, of which 50,000 are children.

About two thirds of outbreaks are in care homes but places such as hospitals, nurseries and schools are also at risk.

Workers who can be badly affected include health and care workers, childcare staff, military personnel, cruise ship employees, flight attendants and food handlers.

The new trial is part of the government’s 10-year strategic partnership with Moderna, under which the pharmaceutical company is building a new mRNA research, development and manufacturing site and investing in UK clinical trials.

“This novel vaccine could make a difference to the lives of many – especially our most vulnerable citizens – and reduce the burden of seasonal illness on the NHS," said Prof Lucy Chappell, NIHR chief executive and chief scientific adviser to the Department of Health and Social Care.

“Leveraging the UK’s expertise in vaccine development, the DHSC through the NIHR and Moderna are delivering this large-scale trial at pace, so that people across the UK and the world can benefit sooner.”