Brace yourself—this winter might be a doozy, thanks to a new flu strain that’s already stirring up trouble. Experts warn this could be the worst flu season in a decade, and here’s why you should pay attention. But here’s where it gets controversial: while some are sounding the alarm, others argue it’s too early to predict the full impact. So, what’s really going on?
Every winter brings the flu, but this year feels different. A seasonal flu virus unexpectedly mutated during the summer, seemingly bypassing some of our immunity. It’s kicked off the flu season over a month early, and history suggests this particular strain could pack a heavier punch. The NHS has even issued an urgent plea for people to get their flu shots, as fears grow of a brutal winter ahead.
There’s a lot of nuance here, but leading experts aren’t ruling out the possibility of a severe season. ‘We haven’t seen a virus like this in a while,’ says Prof Nicola Lewis, director of the World Influenza Centre at the Francis Crick Institute. ‘It’s concerning—I’m not panicking, but I’m definitely worried.’
So, what’s driving this? Scientists track flu viruses because they constantly mutate, requiring the seasonal vaccine to be updated annually. This process follows a pattern called ‘shift and drift’—minor changes most of the time, with occasional abrupt shifts due to significant mutations. That’s exactly what happened in June this year, when seven mutations appeared in an H3N2 strain, sparking a rapid rise in cases, according to Prof Derek Smith of the University of Cambridge.
And this is the part most people miss: this mutation occurred outside the typical flu season, in the middle of summer in the northern hemisphere. ‘It’s almost certain to spread globally,’ Prof Smith notes. By September, as kids returned to school and temperatures dropped, cases began to climb.
While researchers are still studying these mutations, they likely help the virus evade the immunity we’ve built up over years of flu infections and vaccinations. The result? The virus is spreading more easily, which is why the flu season has started so early in the UK, Japan, and other countries. But here’s the kicker: this strain doesn’t need the usual winter conditions—like crowded indoor spaces—to thrive.
‘We’re way ahead of schedule,’ says Prof Lewis. ‘This is shaping up to be a strong flu season.’ Remember the R number from the pandemic? It’s higher for this strain—1.4 compared to the usual 1.2 for seasonal flu. That means if 100 people had the flu, they’d pass it to 140 this year, versus 120 in a typical year.
Could this be the worst flu season in a decade? ‘It’s highly likely to be bad, and it’s already here,’ warns Prof Christophe Fraser of the University of Oxford. ‘There are signs it could outpace recent years.’ Typically, one in five people get infected, but that number could rise this year.
But predictions aren’t set in stone. Some look to Australia, which faced its worst flu season ever this year, though their strain wasn’t the same H3N2 we’re dealing with. The virus is spreading fast among children in schools, but a 10-year-old’s immunity is vastly different from their grandparents’, who’ve weathered far more flu seasons. Experts will be watching closely as it moves into older age groups.
‘This is a nastier virus,’ Prof Lewis emphasizes. H3N2 strains are historically more severe, especially for older adults. While some may get the flu with no symptoms, others face sudden fever, body aches, and exhaustion. For vulnerable groups, it can be deadly. Last year, nearly 8,000 people died from the flu, and the 2022-23 season saw nearly 16,000 deaths. The NHS is bracing for impact.
So, what can we do? The clear advice is to get the flu vaccine. The NHS has issued an ‘SOS’ with 2.4 million slots available in the next week. ‘This is the most critical year to get vaccinated,’ Prof Lewis urges. But here’s the catch: this year’s vaccine isn’t a perfect match for the mutated strain. It was designed in February, before the new variant emerged in June.
‘Some protection is better than none, but it’s not ideal,’ Prof Fraser admits. The vaccine will still trigger antibodies, but its main benefit may be reducing severity rather than preventing infection. Meanwhile, doctors are being reminded that early antiviral treatment can lower complication risks.
Japan, also facing an early flu season, has closed schools to curb outbreaks—not full lockdowns, but short-term measures to disrupt spread. Nobody knows for sure what’s coming. ‘It might fizzle out by next week,’ says Prof Lewis, ‘but I doubt it.’
Here’s the big question: Are we prepared for what this flu season might bring? And should we rethink how we approach annual vaccinations? Share your thoughts in the comments—let’s spark a conversation!
