This is The Guardian.

This year in the UK, flu season has rolled around rather early.

The flu season is kicking off much earlier and more vigorously in the northern hemisphere

when we've seen for really quite a few years now.

It is looking like it's going to be a challenging season for influenza.

Its premature arrival has prompted concern among scientists and public health experts,

with hospitals bracing for a once-in-a-decade flu surge over the coming winter.

Anyone who's been paying attention to what happens in the winter will know that a bad flu year

can have difficult consequences.

Even in a good year, we have thousands of excess deaths caused by flu each winter.

And so today I'm speaking to Ian Sampal to ask about the strain behind this surprising start,

what kind of protection vaccines might offer this year,

and how best to look after yourself and others if the flu strikes.

From The Guardian, I'm Madeleine Finley, and this is Science Weekly.

Hi Ian. Now, experts have recently been raising the alarm about this year's flu season. It seems to have started pretty early, hasn't it?

It has. I mean, in the northern hemisphere, the flu season normally runs from mid-November to mid-February thereabouts.

Now, it's hard to know for sure when the season starts because obviously most healthy people never come to the attention of their doctors or the hospitals.

They might just have like a day or two off school or work. So what we do is we actually rely on

hospital and GP data, which is really picking up the more serious cases. And what we do

is we call the start of the season when 10% of the suspected cases test positive. That's when

we say, OK, the flu season has started. This year, at the start of November, we were already at 11% test positivity.

So just to compare it with the same time last year, at the start of November, only about 3% were testing positive.

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