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Flu And COVID-19 Surveillance Report Published - 9 January 2025
![Image by Bruno from Pixabay]()
Image by Bruno from Pixabay
This bulletin (formally Weekly Winter Briefing) brings together the latest surveillance data, along with the latest public health advice for flu, COVID-19, RSV and other viruses common in winter.
In week 1:
COVID-19 activity remained stable across most indicators and was at baseline activity levels
influenza (flu) activity showed a mixed picture with some indicators suggesting that activity may have reached a peak, though activity remains at high levels
Respiratory syncytial virus (RSV) activity decreased across most indicators and was circulating at low levels
For more information, see the f
lu, COVID-19 and RSV surveillance report and
norovirus surveillance report.
Flu surveillance data for week 1
Flu activity showed a mixed picture with some indicators suggesting that activity may have reached a peak, though activity remains at high levels
flu positivity decreased slightly with a weekly mean positivity rate of 28.1%, compared to 29.7% in the previous week. This is based on a percentage of people who test positive among those with symptoms tested at sentinel “spotter” laboratories, reported through the Respiratory DataMart surveillance system
overall, flu hospitalisations remained stable at 13.41 per 100,000, compared with 13.90 per 100,000 in the previous week
the weekly influenza-like illnesses (ILI) General Practice (GP) consultation rate increased to 20.6 per 100,000 compared with 13.9 per 100,000 in the previous week
up to the end of week 1, vaccine uptake stood at 38.6% of those under 65 years in a clinical risk group, 33.8% in all pregnant women and 73.8% in all those aged 65 years and over. 40.9% of children aged 2 years of age and 42.5% of children aged 3 years of age have been vaccinated
COVID-19 surveillance data for week 1
COVID-19 activity remained stable across most indicators and was circulating at baseline levels
COVID-19 positivity in hospital settings decreased with a weekly mean positivity rate of 2.2%, compared to 2.5% in the previous week
COVID-19 hospitalisations remained stable at 1.39 per 100,000 compared to 1.32 per 100,000 in the previous week
COVID-19 ICU admissions remained stable at 0.06 per 100,000 compared with 0.04 per 100,000 in the previous week
there were 12 COVID-19 acute respiratory incidents reported in week 1
the highest hospital admission rate was in the North-East at 2.78 per 100,000, increasing from 1.68 per 100,000 in the previous week
those aged 85 years and over had the highest hospital admission rate, which increased to 15.36 per 100,000 compared with 12.64 per 100,000 in the previous week
up to the end of week 1, 23.5% of those under 65 years in a clinical risk group and 59.1% of all people aged over 65 years old, who are living and resident in England had been vaccinated
Respiratory syncytial virus (RSV) surveillance data for week 1
Respiratory syncytial virus (RSV) activity decreased across most indicators and was circulating at low levels overall
emergency department attendances for acute bronchiolitis decreased
RSV positivity decreased slightly to 6.2% compared with 7.2% in the previous week
overall, hospital admissions decreased to 2.14 per 100,000 compared with 2.48 per 100,000 in the previous week
Dr Conall Watson, Consultant Epidemiologist at UKHSA, said:
"We are continuing to see high levels of flu this week and ongoing admissions to hospitals and intensive care. Although activity has remained stable coming into the new year, influenza activity can be unpredictable as people return to work and school and opportunities for the virus to spread can increase.
"The predominant circulating flu strain continues to be A H1N1 clade 5a.2a, and the World Health Organization has so far concluded that the H1 component of the flu vaccine is well matched. If you’re still offered a vaccine through local services, it’s important that you take this up, including if you are pregnant or a health and social care worker.
"If you have symptoms of flu or COVID-19 such as a high temperature, cough and feeling tired and achy, try to limit your contact with others, especially those who are vulnerable. If you have symptoms and need to leave the house, our advice remains that you should consider wearing a face covering. Washing hands regularly and using and disposing tissues in bins can reduce the spread of respiratory illnesses."
Norovirus surveillance data for week 52
Norovirus activity has decreased in recent weeks, with reports in the 2-week period between 16 to 29 December 2024 12.1% lower than the previous 2-week period. The decrease over the festive period has also been seen in previous years and should be interpreted with caution as it likely reflects changes in patterns of healthcare use, social mixing and lagged reporting due to the Christmas holidays, as well as the impact of school holidays. However, the total number of reports was 63.6% higher than the 5-season average for the same 2-week period.
Rotavirus reporting has decreased in recent weeks and was within expected levels during the 2-week period of weeks 51 and 52.
The number of norovirus outbreaks reported to the Hospital Norovirus Outbreak Reporting System (HNORS) since the start of the 2024/2025 season is 11.7% higher than the 5-season average.
Norovirus reporting remained high across all regions of England and all age groups, with the highest number of reports in adults aged 65 years and over.
While some of the increased reporting may be attributable to the increased use of PCR multiplex technology (capable of detecting multiple gastrointestinal pathogens in one test), it is likely that 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 high levels.
During the 2024/2025 season to date, the majority (89.5%) of samples characterised were norovirus genogroup 2 (GII), of which the most frequently identified genotype was GII.17 (59.7%), an increase of this genotype has also been observed in other counties during 2024 and is being closely monitored — at present there is no indication it leads to more severe illness (note: it isn’t accurate to refer to GII.17 as ‘Kawasaki’ and this term is causing confusion with Kawasaki Disease, which is an unrelated disease)
Laboratory reports represent just a small proportion of total norovirus cases and it has been estimated that for every case of norovirus reported to national surveillance in the UK there are about 288 in the community that go unreported, representing an annual burden of around 3 million cases.
Norovirus symptoms include nausea, vomiting and diarrhoea but can also include a high temperature, abdominal pain and aching limbs. Norovirus infections can cause dehydration, especially in vulnerable groups such as young children and older or immunocompromised people, so if you do get ill it is important to drink plenty of fluids during that time.
Amy Douglas, Epidemiologist at UKHSA, said:
"Although there was a decrease in reports of norovirus over the festive period, cases still remain high and we expect levels to rise further with the return to school.
"If you have diarrhoea and vomiting, you can take steps to avoid passing the infection on. Do not return to work, school or nursery until 48 hours after your symptoms have stopped and don’t prepare food for others in that time either. If you are unwell, avoid visiting people in hospitals and care homes to prevent passing on the infection in these settings.
"Washing your hands with soap and warm water and using bleach-based products to clean surfaces will also help stop infections from spreading. Alcohol gels do not kill norovirus so don’t rely on these alone."