Flu vaccine updated to target Super-K strain as NHS rollout begins

First doses from Tuesday

Last winter the flu arrived early, more than a month ahead of schedule, carrying a new mutated version of the virus.

This mutated version was a seasonal influenza known as subclade K, or Super-K.

What Super-K flu actually means

"Super flu" is not a medical term, and it does not mean the virus has become harder to treat. It means people have not yet built up immunity to it.

Flu vaccines are updated every year to keep them matched to the type of flu circulating, with experts having to predict how the viruses will mutate ahead of time.

This year's has had a few tweaks, including one to better match subclade K.

Nobody knows yet when flu will hit this year, or how bad the season will be.

Experts often look to the southern hemisphere for a steer, Australia and New Zealand peak in July or August, and both have so far had a relatively mild year in terms of cases.

Who gets the flu vaccine, and when

Since they catch and spread flu easily, schoolchildren are being prioritised.

Protecting them also helps others, including baby brothers and sisters and grandparents.

Like pregnant women, they can get the jab from Tuesday.

Other eligible groups, including people aged 65 and over, can get a free NHS flu shot from October and should receive an invite by phone or post.

Dr Amanda Doyle of NHS England said it was best to be cautious.

"Last year's flu season came early and was made worse by a new variant, which had a major impact for patients and put enormous pressure on urgent and emergency care services across the country," she said.

"With the NHS experiencing its busiest summer on record, staff have started preparing for this winter earlier than ever – and with services already under significant pressure, it is vital that everyone offered the vaccine comes forward."

That summer brought public health pressures of its own, with heat deaths recorded across England and Wales through the UK's run of heatwaves. Flu "can really knock you for six", Doyle said.

Everyone is at risk of catching it, whatever your age and however fit and healthy you are.