Latest UKHSA weekly winter virus surveillance data
Report monitoring respiratory viruses for the 2026/27 season.
This weekly bulletin brings together the latest surveillance data, along with the latest public health advice for flu, COVID-19, Respiratory Syncytial Virus (RSV) and other viruses.
For respiratory viruses, in the week between 28 September and 4 October 2026:
- Influenza activity increased and is circulating at baseline levels
- COVID-19 activity increased and is circulating at low levels
- Respiratory syncytial virus (RSV) activity remained low and is circulating at baseline levels
The flu, COVID-19 and RSV surveillance report and the national norovirus and rotavirus surveillance reports: 2026 to 2027 season are published weekly.
Flu surveillance data for week 40 (28 September and 4 October 2026):
- Influenza activity increased and is circulating at baseline levels
- Flu positivity increased with a positivity rate of 6.5% compared with 5% on the previous week.
- overall, flu hospitalisations were 1.97 per 100,000. This surveillance formally starts in week 40 so a comparison to the previous week is not possible.
COVID-19 surveillance data for week 40 (28 September and 4 October 2026):
- COVID-19 activity increased and is circulating at low levels
- COVID-19 positivity increased with a weekly positivity rate of 9.1% compared with 7.9% in the previous week.
- COVID-19 hospitalisations increased to 2.04 per 100,000 compared with 1.75 per 100,000 in the previous week
- COVID-19 ICU admissions remained low at 0.06 per 100,000 compared with 0.05 per 100,000 in the previous week
Respiratory Syncytial Virus (RSV) surveillance data for week 40 (28 September and 4 October 2026):
- RSV activity remained low and is circulating at baseline levels
- RSV positivity increased to 0.5% compared with 0.3% in the previous week.
- the overall weekly hospital admission rate for RSV remained low at 0.11 per 100,000 compared with 0.13 per 100,000 in the previous week
Norovirus surveillance data between weeks 39 and 40 of 2026
Norovirus activity remains low and within expected levels for this time of year.
Overall, norovirus laboratory reports between weeks 39 and 40 of 2026 (21 September 2026 to 4 October 2026) were 9.8% lower than the 5-season average for the same 2-week period.
Rotavirus activity between weeks 39 and 40 of 2026 was 13.9% higher than the 5-season average for the same 2-week period and has remained within expected levels.
The number of norovirus outbreaks reported to the Hospital Norovirus Outbreak Reporting System (HNORS) since the start of the 2025/2026 season is 19.2% lower than the 5-season average.
During the 2025/2026 season to date, the majority (87.2%) of samples characterised were norovirus genogroup 2 (GII), of which the most frequent genotype identified was GII.4 (25.6%).
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 become ill, it is important to drink plenty of fluids during that time.
There are simple steps we can all take to help stop norovirus from spreading. Wash your hands with soap and warm water and use bleach-based products to clean surfaces to help stop infections spreading. Alcohol gels do not kill norovirus, so don’t rely on these alone.
If you have diarrhoea and vomiting, don’t return to work, school or nursery until 48 hours after your symptoms have stopped, and don’t prepare food for others during that time either. If you are unwell, avoid visiting people in hospitals and care homes to prevent passing on the infection to those who are most vulnerable.