The UK Health Security Agency (UKHSA) has issued a warning for people to stay at home for 48 hours if they catch the highly contagious G11.17 strain of norovirus, with cases on the rise. The variant has been responsible for most cases in the 2024/25 winter season, according to the agency’s weekly update. The report also highlighted that norovirus activity is now increasing across all age groups, with the biggest increase in adults, particularly those aged 65 years and over.
Between November 4 and 17, 2024, there was a 31.6% rise compared to the previous fortnight. Total reports were almost double the five-season average for the same period. The number of norovirus outbreaks reported to the Hospital Norovirus Outbreak Reporting System (HNORS) since the start of the 2024/2025 season is 19.4% higher than the five-season average. While some of the increased reporting may be due to the increased use of PCR multiplex technology, the emergence of an unusual norovirus genotype, GII.17, as well as changes in the epidemiology following the COVID-19 pandemic and other factors, are contributing to the observed rise.
The UKHSA revealed that the majority (89%) of cases this season have been identified as norovirus genogroup 2 (GII), with the most common being GII. 17 (66.3%). This strain has also been on the rise in other areas throughout 2024 and is being closely monitored. However, officials stress that there is currently no indication that it leads to more severe symptoms.
Symptoms of norovirus include nausea, vomiting, diarrhoea, high temperature, abdominal pain, and aching limbs. Norovirus infections can lead to dehydration, particularly in vulnerable groups such as young children, the elderly, and those with weakened immune systems, so it is crucial to drink plenty of fluids if you fall ill.
Amy Douglas, an epidemiologist at UKHSA, advised those who have caught the virus to avoid passing the infection on by staying home for 48 hours after symptoms have stopped, refraining from preparing food for others during that time, and avoiding visiting people in hospitals and care homes. Regular handwashing with soap and warm water and using bleach-based products to clean surfaces are also recommended to prevent the spread of infections, as alcohol gels do not kill norovirus.
In addition to the norovirus warning, the weekly update also provided updates on COVID, flu, and Respiratory Syncytial Virus (RSV). COVID levels remained stable, while flu and RSV cases had increased. The agency advised on spotting signs of serious RSV infection and stressed the importance of vaccinations against flu, COVID-19, and RSV to protect against these diseases during the winter period.
Insights and Summary:
The UK Health Security Agency’s warning about the G11.17 strain of norovirus highlights the importance of taking precautions to prevent the spread of this highly contagious virus. With cases increasing across all age groups, it is crucial for individuals to stay home if they fall ill, practice good hygiene, and consider vaccination against flu, COVID-19, and RSV. The rise in winter illnesses serves as a reminder of the ongoing need to protect vulnerable groups and take proactive measures to safeguard public health.