The Joint Committee on Vaccination and Immunisation (JCVI) reviewed the latest UK influenza immunisation programme data, including uptake, epidemiology and vaccine effectiveness for the 2024 to 2025 season at the influenza sub-committee meeting on 13 May 2025 and the JCVI meeting on 4 June 2025.
The 2024 to 2025 influenza season started in the second half of November 2024, with the peak of activity occurring just before the start of 2025. There was a relatively high burden of disease over the season, with influenza-attributable excess mortality higher than in the 2023 to 2024 season and with more paediatric deaths reported.
Following JCVI advice in 2023, the start of the adult influenza programme (except for pregnant women) was moved from September to October. This was based on evidence that vaccine effectiveness can wane over time in adults, and therefore if vaccination is given closer to the start of the influenza season, vaccine effectiveness will be higher during peak influenza activity. The timing of the programme did not change for pregnant women as vaccination needs to occur prior to delivery to protect the baby in the first few months of life, while also protecting the mother during peak season. The timing of the children’s programme also did not change as protection from vaccination lasts longer in children.
Coverage was lower than the 2023 to 2024 season for adults, while it remained similar for children. The ongoing low or declining coverage, specifically in clinical risk groups, pregnant women and frontline healthcare workers, is concerning, especially given the impact vaccination has on preventing hospitalisation: recently published modelling estimates suggested that the influenza vaccination programme prevented approximately 100,000 hospitalisations in the 2024 to 2025 season.
Vaccine effectiveness is important in determining the vaccines used in the programme. Current vaccines provide moderate effectiveness, ranging from 30% to 70% depending on age, setting and vaccine type, with the highest effectiveness seen against hospitalisation.
Recent improvements in surveillance through the use of the national vaccine registry and the expansion of primary care sentinel surveillance have supported informative comparisons between vaccine types. Unpublished data from the UK Health Security Agency (UKHSA) for the live attenuated influenza vaccine (LAIV) used in the children’s programme suggested that vaccine effectiveness against influenza A(H1N1) was lower than for the inactivated influenza cell-culture vaccine (IIVc) over the past 3 seasons combined, although the confidence intervals were overlapping. While this reduction in effectiveness is of concern to JCVI, LAIV is still an effective vaccine that is preventing hospitalisations in children.
Unpublished analyses undertaken by UKHSA on vaccine effectiveness against hospitalisation for adults over 65 years showed overlapping confidence intervals for the 3 vaccines that were used in the 2024 to 2025 season: adjuvanted inactivated influenza vaccine (aIIV), IIVc and high-dose inactivated influenza vaccine (IIV-HD). Previous analyses have shown lower vaccine effectiveness for the inactivated influenza egg-culture vaccine (IIVe), which reinforces the current JCVI advice not to use this vaccine for adults aged 65 years and over.
In those groups where the use of IIVe remains an option, this should only be in circumstances where the preferred first-line influenza vaccines are not available and efforts should be made to use the best available influenza vaccines, particularly in clinical risk groups.
JCVI has previously advised that they would like to see more use of inactivated recombinant influenza vaccine (IIVr) in the programme to improve estimates of vaccine effectiveness and have data over multiple seasons on the performance of this vaccine, especially in older adults where there is strengthening evidence of additional benefit relative to other products. This advice remains.
The advice below represents JCVI’s scientific view on the use of influenza vaccines in the UK for the 2026 to 2027 influenza season.
