The UK is experiencing an unusually early and significant flu season, with health officials confirming a new strain is behind the surge in cases.
Data from the UK Health Security Agency (UKHSA) indicates the H3N2 flu strain now constitutes the majority of infections, driving a sharp increase in illnesses, particularly among children and young adults.
What is the new H3N2 flu strain?
Influenza viruses constantly evolve, much like COVID-19. The H3N2 strain is a specific type of flu that has continued to mutate after the composition of this year's annual flu vaccine was finalised.
This evolutionary step means population immunity is lower, explaining the higher infection rates and the season's premature start. Global agencies, including the World Health Organisation (WHO), monitor these strains to inform future vaccine development.
Recognising the symptoms
Despite being a new strain, the symptoms of H3N2 flu are consistent with traditional seasonal flu. Early signs you may have contracted the virus include:
- A blocked or runny nose
- Sneezing and a sore throat
- A hoarse voice and a new cough
- General tiredness and fatigue
Additional symptoms can involve headaches, difficulty sleeping, loss of appetite, and gastrointestinal issues like diarrhoea, tummy pain, or vomiting.
The vital importance of vaccination
Health authorities are issuing a strong plea for all eligible individuals to get their flu jab without delay. Despite the strain's evolution, the vaccine remains the best defence.
Latest UKHSA data shows the vaccine is 70-75% effective at preventing flu hospitalisation in children aged 2 to 17, and 30-40% effective in adults.
Dr Alex Allen, Consultant Epidemiologist at UKHSA, commented on the unpredictable virus trends, stating: "We still expect to see further increases as we head into the colder winter months... it's particularly important if you're eligible, to get vaccinated - it remains our best defence against severe illness and hospitalisation."
Echoing this, Dr Jamie Lopez Bernal, Consultant Epidemiologist for Immunisation, affirmed: "Whatever strains do circulate here this winter, we can be confident that the vaccine will still help to protect those most vulnerable from developing serious illness."
With colder weather encouraging indoor mixing, the window to build protection before the festive period is critical. Those eligible for the free NHS flu vaccine are urged to book an appointment immediately if they have not already done so.
