Hospitals across the UK are preparing for a potentially severe flu season driven by a mutated strain of the virus that may be more transmissible than usual. The variant, a subtype of H3N2, has become dominant after emerging through antigenic drift and has triggered an early start to the flu season, more than a month ahead of schedule.
Health officials are particularly concerned because the mutated virus is spreading widely in younger people and is expected to cause a wave of hospital admissions when it reaches older, more vulnerable populations. The R value for the current strain is estimated at 1.4, compared with a typical seasonal flu R of 1.1 to 1.2, indicating higher transmissibility.
NHS managers are ramping up vaccination efforts for staff and communities, expanding same-day emergency care, and treating more patients in the community to reduce hospital stays. The efforts come as resident doctors in England continue a five-day strike over pay, prompting hospitals to implement contingency plans involving consultants and other staff taking extra shifts.
Scientists first detected the mutated strain in June, and genetic analysis shows it is a descendant of a variant that fueled Australia’s worst flu season on record, with over 400,000 lab-confirmed cases. Early data from the UK Health Security Agency (UKHSA) suggests current vaccines are less effective at preventing infection but still provide good protection against severe disease, with vaccine effectiveness against hospital attendance at 70-75% in children and 30-40% in adults.
Flu cases are highest in children but are rising in older people, and health officials expect numbers to increase further as colder weather drives more indoor mixing. Less than a third of people with long-term health conditions have received the vaccine, prompting calls for eligible individuals to get vaccinated and take precautions to stay well this winter.
