Health experts are on high alert as skyrocket to their highest levels since records began in 2014.
The UK Health Security Agency () reports a second wave of the dreaded vomiting bug is causing havoc and experts fear we have not yet seen the worst of it. Despite hopes that warmer would see a decline in cases, as has been the trend in previous years, the current season's rates are still climbing at a rate not seen since for 11 years.
In the fortnight from February 3 to February 16, confirmed cases shot up by 29.4 per cent from the previous two weeks and were a staggering 168.0 per cent above the five-season average for this period. The elderly are particularly at risk, with and care homes battling high infection rates among those aged 65 and over.
A UKHSA spokesperson said: "The increased activity this season is associated with the recently emerged GII.17 genotype. However, the latest data shows that a different but commonly seen genotype - GII.4 - is now increasing."
They added: "Prior to the emergence of GII.17, GII.4 is the genotype that is most commonly detected and increased each winter. While the GII.17 genotype remains dominant, accounting for 59 per cent of cases, its prevalence has dropped from 76 per cent since November. Meanwhile, the GII.4 strain has seen a sharp rise, now representing 29 per cent of cases compared to just 10% three months ago."
This alarming trend suggests that individuals who have already suffered from norovirus this season could be re-infected, as immunity to one genotype doesn't guarantee protection against another, reports . Neither strain of the virus is thought to cause a more severe illness than the other.
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Norovirus symptoms
Common symptoms include:
Certain individuals, especially young children, older adults and those with weakened immune systems, are more prone to severe symptoms which can lead to dehydration. Those experiencing these symptoms should ensure they drink plenty of fluids to prevent this.
Avoid hospital, work, school or nurseryAmy Douglas, the lead epidemiologist at UKHSA, warned: "Norovirus levels are still exceptionally high and now with multiple genotypes spreading at the same time, people could end up getting infected more than once this season. We are seeing the biggest impacts in health and social care settings, such as hospitals and care homes. Symptoms of norovirus can be more severe in older adults, young children and those who are immunocompromised.
"If you have diarrhoea and vomiting, please do not visit hospitals and care homes or return to work, school or nursery until 48 hours after your symptoms have stopped and don't prepare food for others, as you can still pass on the virus during this time. Alcohol gels do not kill norovirus. Wash your hands with soapy warm water and clean surfaces with bleach-based products where possible to help stop infections from spreading."
UKSA further explained that the new genotype has led to a surge in cases due to a lack of previous immunity. However, the high numbers may also be a reflection of UKHSA's enhanced testing capabilities and changing patterns of infection since Covid.
Norovirus is known to spread more easily in lower temperatures as people tend to spend more time indoors and it typically peaks during winter months. Experts at UKHSA estimate that the reported cases only represent a small fraction of the actual infections. For every case reported to national surveillance, approximately 288 cases occur in the community, suggesting around three million cases annually in the UK.
