Question to the Department of Health and Social Care:

To ask His Majesty's Government whether they have identified the virus which has been responsible for the highest incidence of influenza in Autumn/Winter 2022/2023; and whether they have assessed the effectiveness of the influenza vaccine deployed over the same period in countering that virus.

The most prevalent influenza virus this season in England is of the A/H3N2 subtype, with smaller numbers of A/H1N1 detected and fewer still influenza type B. UK Health Security Agency (UKHSA) is currently analysing vaccine effectiveness against influenza requiring healthcare, including the different types and will be contributing this to the World Health Organization 2023/24 vaccine strain selection meeting taking place in February of this year.

More detailed genomic description of the influenza strains analysed by the UKHSA national Respiratory Virus Unit are available in the weekly surveillance report. UKHSA’s assessment of relative prevalence of influenza viruses is based on detections in the UKHSA Royal College of General Practitioners primary care sentinel virological surveillance system and detections in the UKHSA Respiratory DataMart sentinel laboratory surveillance system.