A new strain of norovirus is dominating the UK, with cases of the winter vomiting bug currently double the average for the last five years.

The GII.17 strain is thought to have originated in China and Japan around 2014, but has only recently taken hold in Europe.

Variants which are part of this lineage have been widely nicknamed ‘Kawasaki’ due to their place of origin, although they bear no relation to Kawasaki Disease which is a rare but serious lymph node syndrome mainly affecting children.

The UK Health Security Agency (UKHSA) said that there has been an increase in the proportion of GII.17 norovirus samples in England since April this year.

‘During the first 12 weeks of the 2024/2025 season this was the most commonly detected norovirus genotype,’ they said.

It is overtaking the previous dominant strain, GII.4 and contributing to higher than normal levels of the severely unpleasant bug, which strikes fear in the heart of hospitals and nurseries.

Outbreaks reported in hospitals were 26% higher than the 5-season average, according to the most recent figures.

However, the government said part of the reason for increased reports of norovirus could be better testing and surveillance, and stressed that there is no indication the new strain causes more serious illness.

What is the ‘Kawasaki’ norovirus?

It is still the same norovirus which we know and do not love, which causes diarrhoea and vomiting, with some of those infected also experiencing a fever and headache.

But similar to how Covid-19 continued evolving into different variants, norovirus does the same with new variants having some kind of selective advantage making them spread more easily.

In May this year, Dr David Allen of the London School of Hygiene & Tropical Medicine (LSHTM), said: ‘In the early part of this year, a different group, called GII.17, has been associated with an increase in the proportion of norovirus cases.

‘Research suggests that being previously infected by GII.4 viruses may not protect against infection with GII.17 norovirus.’

Thousands of Brits end up in hospital every year due to the highly contagious virus, particularly over winter although it can be caught at any time.

Globally, it causes about 200,000 deaths annually – a quarter of which are children.

There are around 80 deaths each year from norovirus in the UK, typically older adults and immunocompromised patients.

Anyone who has symptoms are urged to avoid visiting the hospital until they have been symptom free for 48 hours.

NHS Infection Prevention and Control Nurse Christine Woodgate said in a TikTok video: ‘If you are feeling or being sick, have diarrhoea or have a temperature, headache, or aching in your arms or legs, it could be norovirus.’

The world’s first vaccine against norovirus has been trialled in UK hospitals, using the same tech employed in the Covid jab.

The new mRNA vaccine from Moderna is due to enter its final stages of testing in the next couple of weeks, with results so far indicating it prompts a ‘strong immune response’.

Chief investigator of the study Dr Patrick Moore said the lack of a vaccine currently means seriously ill people in hospital can only be treated with intravenous fluids.

He said: ‘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.’

How to avoid catching norovirus

According to the NHS, washing hands frequently with soap and water is the best way to stop the vomiting bug from spreading.

This is particularly important because the virus is not killed by hand sanitiser gel due to its strong protein membrane, so you should throw it back to Covid times and sing happy birthday while getting a proper wash in, which does give protection.

Avoiding close contact with someone who has the virus, and avoiding eating food handled or prepared by them also limits risk.

Using a bleach-based cleaner in your home is a good idea if someone else is ill with the virus.

Get in touch with our news team by emailing us at webnews@metro.co.uk.

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