Why is norovirus reporting in England so high at the moment?

Data for the current 2024/2025 season in England shows that norovirus laboratory reports are notably higher than the 5-season average. Norovirus cases typically increase through autumn and into winter, but this year cases have risen earlier than usual and are expected to continue to increase. This rise comes alongside a shift in circulating common norovirus genotypes.

UK Health Security Agency surveillance systems reveal several key patterns, including increased laboratory confirmed norovirus cases in all age groups, significant impact of norovirus outbreaks in healthcare settings and genetic diversity.

Several factors are likely contributing to the unusual norovirus activity we’re seeing this season. These include:

• Post-pandemic changes in population immunity.
• Changes in diagnostic testing capabilities.
• Changes in reporting to national surveillance.
• A true rise in norovirus transmission due to the emergence of GII.17.

There's currently no indication that GII.17 causes more severe illness, but work is underway to conduct further assessment of severity. 

To reduce the spread of norovirus, wash your hands thoroughly with soap and warm water, as alcohol-based hand sanitisers are not effective against the virus. Stay at home for at least 48 hours after symptoms stop and disinfect surfaces using a bleach-based cleaner where possible.

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Source: UK Health Security Agency, 29 November 2024