Sharp rise in flu cases at the start of the festive period, with peak still to come
Source: UKHSA, 9 December 2025
With just 3 weeks until Christmas, the UK Health Security Agency is urging all eligible groups to ensure they help protect themselves against flu and RSV as cases sharply increase. The latest data shows that cases of flu and RSV have risen significantly in the past week and we are now seeing more flu cases among adults. Flu hospitalisations have increased by 63% in the past week and with increased mixing and socialising over the next few weeks, this is expected to exacerbate these increases further.
The flu vaccine offers the best protection against severe illness and hospitalisation. However, it can take up to 2 weeks following vaccination to develop antibodies and an immune response. This is why – with just 3 weeks until Christmas – it’s important that anyone who is eligible books an appointment now to ensure they have the best protection possible in time for the festive period.
This week’s data also shows that cases of RSV continue to increase despite the later start this year to the RSV season, so it’s important that eligible groups make sure they are vaccinated. For RSV, pregnant women are offered the vaccine from 28 weeks and it is recommended during every pregnancy to help provide the best protection for newborn babies, who are at highest risk. RSV also impacts older adults and can cause severe illness, which is why those aged 75 to 79 or who turned 80 years old after 1 September 2024 are also offered the vaccine.
Those who are eligible for the flu vaccine are at most risk of serious complications from flu. This includes everyone over 65, those who are pregnant, or those with certain long-term health conditions.
School-aged children in reception to Year 11 are offered the vaccine through school while parents can book an appointment at their GP surgery for 2 and 3 year olds. If your child missed their flu vaccine in school, they should still able to visit local community clinics to get protected.
In the week between 24 and 30 November 2025:
- influenza activity increased and is now circulating at medium levels
- respiratory syncytial virus (RSV) activity increased and is now circulating at medium levels
- COVID-19 activity was stable and is at baseline levels