A bold warning: this winter could be among the toughest in NHS history as flu cases surge, and the same strain is taking hold across continental Europe. The virus is mutating in ways that may spread more quickly, while vaccines aren’t as effective as hoped.
Overview
The NHS is bracing for a potentially record-breaking winter, with a spike in flu placing heavy demands on GP practices, hospitals, and ambulance services. Across continental Europe, the same flu strain driving the UK’s outbreak is now behind a new wave of infections.
When does flu season start?
In the northern hemisphere, flu season typically runs from mid-November to mid-February, though it can begin as early as October and extend into May. Public health officials deem the season started when 10% of suspected cases test positive for influenza. At the start of November, England recorded 11% positivity, up from 3% at the same point last year, suggesting the season began roughly four to five weeks earlier than usual.
What’s driving this year’s outbreak?
Seasonal flu involves multiple circulating strains, primarily influenza A and influenza B. Among influenza A subtypes, H1N1 and H3N2 are common. In the UK, H3N2 has been dominant so far. This year’s H3N2 lineage traces back to a strain that caused Australia’s worst flu season on record. Since then, the virus has acquired seven new mutations, creating a drifted form referred to as subclade K. These mutations are believed to help the virus spread more readily, though they don’t appear to cause more severe disease.
What’s happening in continental Europe?
Europe is experiencing a similar pattern, but with varying regional impact. The season began three to four weeks earlier overall, though in some areas the drifted H3N2 strain only emerged as the primary driver of infections in recent weeks. Germany’s Robert Koch Institute reported that flu activity started two to three weeks earlier there, with both H1N1 and H3N2 circulating and a notable rise in H3N2 over the last three weeks. In France, cases started a bit later; Dr. Vincent Enouf of the Pasteur Institute noted that France saw the season begin about a week earlier than normal and detected similar levels of H1N1 and H3N2 subclade K.
Public health agency Sante publique France said flu activity was rising strongly across metropolitan France, with increases across all age groups. All metropolitan regions are in the epidemic phase for influenza except Corsica, where cases remain lower. Hospital visits for flu and related admissions have risen in the past week.
Elsewhere in Europe, Spain is experiencing a sharp increase with infection rates already surpassing last winter’s peak and hospitalizations doubling in a week. Romania and Hungary are also seeing surges. In Ireland, nearly 3,000 flu cases were reported in the first week of December, up 49% from the previous week, with hospital admissions up 58%.
Vaccine effectiveness
The drifted H3N2 mutations make the current year’s vaccine less well matched to circulating strains, which reduces its ability to prevent infection. Yet vaccines still offer meaningful protection against severe illness. UK Health Security Agency data show overall vaccine effectiveness against infection is reduced for the drifted H3N2, but protection against hospital attendance and admission remains in the typical range for seasonal vaccines—roughly 70–75% for children and 30–40% for adults in the early season estimates.
Despite reduced infection protection, health authorities urge vaccination to lower the risk of severe disease. France has seen strong uptake, with almost eight million people vaccinated so far, about 21% more than at the same point last year, according to Dr. Enouf.
Severity and risk factors
Among flu patients in intensive care units, older adults (65+) and those with other health conditions are disproportionately represented. In Ireland, about 73% of ICU flu patients had not received the current flu shot. In France, vaccination status among ICU patients was often unknown, but the trend indicates a higher risk for the unvaccinated.
Bottom line
This season’s drifted H3N2 strain is spreading quickly and being only partially matched by the current vaccine, which means more people may experience infection, though vaccines still help reduce severe outcomes. Getting vaccinated remains a prudent step to protect yourself and others, especially if you’re in a high-risk group or work in healthcare.
Important question for readers
With the early start and uneven vaccine protection, how do you weigh vaccination against other protective measures this season? Do you think public messaging should emphasize vaccination more strongly, or should resources shift toward rapid testing and early treatment access? Share your thoughts in the comments.
