Health services across the United Kingdom are preparing for what could be the most significant flu season in ten years, driven by a mutated strain of the virus that is spreading earlier and more widely than usual.
A Perfect Storm: Early Surge and Mutated Virus
Scientists first identified the altered flu virus in June. Genetic analysis reveals it is a descendant of the strain that caused Australia's worst flu season on record, which saw over 400,000 laboratory-confirmed cases. This new version, which evolved through a natural process called antigenic drift, has quickly become the dominant strain in the UK.
This has triggered the start of the flu season more than a month earlier than typical. Professor Antonia Ho from the MRC-University of Glasgow Centre for Virus Research explained, "Whenever there is an early start to the season, there tends to be a bigger peak." One critical reason is that fewer people have had their vaccinations by the time they are exposed to the virus.
The virus is a subtype of influenza known as H3N2, which is notorious for causing more severe illness, particularly in older adults. The recent mutations may make the virus more transmissible, with the R value—the average number of people an infected person passes the virus to—estimated to be 1.4 this season, up from the usual 1.1 to 1.2.
NHS on High Alert as Hospitalisations Loom
NHS managers are urgently implementing measures to cope with the anticipated wave of admissions. These efforts include redoubling vaccination campaigns for staff and the public, expanding same-day emergency care, and treating more patients within the community to avoid hospital stays.
"Last flu season was particularly nasty and we’re very concerned that this year could be even worse," said Elaine Clancy, the group chief nursing officer for St George’s, Epsom and St Helier university hospitals. "We’re preparing for a spike of flu on to our wards."
This pressure comes as resident doctors in England are engaged in a five-day strike over pay, forcing hospitals to activate contingency plans. These involve bringing in consultants for extra shifts and rescheduling non-urgent appointments.
Dr Claire Beynon, the executive director of public health for Cardiff and Vale university health board, confirmed the early trend, stating, "We are seeing a rapid and early increase in influenza this winter and are expecting to see an increase in hospital admissions."
Vaccination Remains the Key Defence
Despite the challenges, health officials are strongly urging all eligible groups to get vaccinated. Early data from the UK Health Security Agency (UKHSA) suggests that while current vaccines may be less effective at completely blocking infection from this specific mutated virus, they still provide substantial protection.
Vaccine effectiveness against hospital attendance and admission is currently estimated at 70-75% in children and 30-40% in adults, which is within the expected range.
Caroline Abrahams, charity director at Age UK, emphasised the urgency: "The new strain of flu is a worry on what was already predicted to be a big flu season. It is more important than ever that everyone that is eligible – including older people – gets the flu vaccine."
Experts note that while H3N2 can lead to severe seasons, it is not a foregone conclusion. A similar situation in 2003/4 resulted in 12,000 flu deaths in England and Wales, which was at the lower end of the typical range. However, with low uptake reported among those with long-term health conditions, the call for vaccination is more critical than ever to prevent the UK from experiencing its most severe flu season in a decade.
