The UK is facing an unusually early and severe flu season, with a concerning variant of the virus putting significant strain on the NHS and posing a heightened risk to vulnerable populations.
An Unusually Early and Severe Threat
Health experts have raised the alarm as flu infections are circulating at a rate not typically seen until early December, marking a start to the season that is five weeks earlier than normal. The dominant virus, identified as influenza A(H3N2), is known for causing more severe illness, particularly in older adults.
Speaking at the NHS Providers conference in Manchester, Dr Antonia Ho, a clinical senior lecturer and consultant in infectious diseases at the University of Glasgow, confirmed the severity. "Of the two seasonal influenza A viruses, the current dominant circulating virus (A/H3N2) tends to cause more severe illness than A/H1N1," she stated.
Rising Hospital Admissions and Mortality Risks
Latest data from the UK Health Security Agency (UKHSA) reveals a sharp increase in hospital admissions. The rate in England has jumped to 3.8 per 100,000 people, up from 2.4 the previous week. While this is below the peaks of recent years, it is a level not usually reached until next month.
The danger is underscored by historical data. Dr Ho highlighted that in the 2022/23 winter season, when A(H3N2) was dominant, there were approximately 16,000 influenza-associated deaths. This is double the 8,000 deaths recorded last winter. The UKHSA's own estimates put the death toll from flu in England at 7,757 last winter, a significant rise from 3,555 the year before. Tragically, child deaths involving flu also increased from 34 to 53.
Vaccine Concerns and Increased Transmissibility
The early arrival of the virus means a smaller proportion of vulnerable people, such as elderly pensioners, have had a chance to receive their flu vaccine. Compounding this issue, the current A(H3N2) virus has acquired seven new mutations over the summer.
This means it is quite different from the strain included in this year's vaccine, potentially reducing the jab's effectiveness. "The virus could have changed sufficiently to escape the immunity that has been built up from previous infections and vaccinations," Dr Ho explained.
Furthermore, the virus has become more contagious. The reproduction number (R) has increased from 1.2 to 1.4, meaning 100 infected people can now infect 140 others, compared to 110-120 in typical flu seasons.
In response to the growing crisis, NHS leaders have issued a 'flu jab SOS', urgently encouraging the public to get protected. This warning is echoed by the experience in Australia, which has just endured its biggest flu season in history and often serves as an accurate predictor of the UK's flu outlook.
