The UK Health Security Agency (UKHSA) has released its first weekly winter respiratory virus surveillance report, indicating that flu activity is increasing. While still at baseline levels, flu trends have been rising since August and are higher than in the same period over the last four winter seasons. The report for week 40 (28 September to 4 October 2026) shows flu positivity at 6.5%, up from 5% the previous week.
The increases in flu are primarily driven by young adults. Overall flu hospitalisations were 1.97 per 100,000. Dr Jamie LopezBernal, Consultant Epidemiologist at UKHSA, stated that with flu levels increasing and the possibility of an early flu season, eligible individuals should get vaccinated.
A recent World Health Organization (WHO) technical report noted that a flu A(H1N1) virus, seen at low levels in Europe and the UK, has 'drifted' compared to the component in this year's flu vaccine. However, it is too early to determine if this drifted virus will circulate widely or how effective the vaccine will be against it. Flu vaccines typically remain effective at preventing severe flu, even when drifted strains are observed.
The report also shows increasing COVID-19 activity, with a weekly positivity rate of 9.1% compared to 7.9% in the previous week. COVID-19 hospitalisations increased to 2.04 per 100,000. Dr Alex Allen, Consultant Epidemiologist at UKHSA, noted that current COVID-19 strains, including XFG, are closely related to those seen for over a year, and there is no evidence they are causing more severe illness or spreading faster.