The current outbreak is driven by a specific subclade of H3N2, named subclade K, which is a descendant of the strain responsible for Australia’s record-breaking flu season earlier this year. Since then, the virus has acquired seven new mutations. While these mutations are thought to facilitate faster transmission and an earlier start to the season, evidence suggests the strain does not cause more severe disease than typical influenza. In England, the flu season began four to five weeks earlier than usual, with 11% of suspected cases testing positive at the start of November, compared to 3% at the same time last year.
The early onset and high volume of cases have led to record hospitalizations. In England, 95% of hospital beds are currently occupied, with the number of patients admitted for flu at its highest on record. Health Secretary Wes Streeting stated in Parliament that the NHS is facing a “challenge unlike any it has seen since the pandemic” and is in an “incredibly precarious situation.” He has urged doctors to postpone their strike, warning that industrial action during the holiday period could be the “Jenga piece that collapses the tower” of the health service.
The strike is being led by junior doctors, who argue that despite a nearly 30% pay rise over the past three years, their real-term earnings remain below 2008 levels when adjusted for inflation. Their union, the British Medical Association, reported that 83% of members voted to proceed with the five-day action, demanding full pay restoration. The timing of the strike, coinciding with the peak of the flu surge, has intensified concerns among NHS leaders about the capacity to handle emergency and urgent care.
While the mutated virus spreads rapidly, it is not causing a higher severity of illness. However, the strain is poorly matched to this year’s seasonal flu vaccine, reducing its effectiveness against infection. Data from the UK’s Health Security Agency indicates that while protection against infection is lower than hoped, the vaccine still provides significant protection against severe disease. For children, protection against hospital attendance and admission remains within the normal range at 70-75%, while for adults, it is estimated at 30-40%. Officials continue to strongly recommend vaccination to mitigate the risk of severe illness and hospitalization.
Similar trends are observed across continental Europe, where the same H3N2 strain is driving a new wave of infections. In Germany, the flu season started two to three weeks early, with a clear increase in H3N2 cases. In France, flu activity is “increasing strongly,” with all metropolitan regions now in the epidemic phase. Data from France shows that 98% of patients in intensive care units with flu who had known vaccination status were not vaccinated. In Ireland, cases rose by 49% in the first week of December, with hospital admissions up 58%. The convergence of high case numbers, reduced vaccine efficacy against infection, and potential staff shortages due to industrial action presents a complex public health challenge for the UK and Europe.
