Flu in four charts – how this year’s winter outbreak is different

The NHS said it was facing a “worst case scenario” after the number of flu patients in hospital rose by 55 per cent in a week.

Sir Jim Mackey, chief executive of NHS England, warned that 5,000 to 8,000 hospital beds could be filled with flu patients by the end of the week.

Health experts at the King’s Fund think tank said talk of a “relentless flu wave” had become worryingly familiar in recent years. But Chris Streather, medical director of the NHS in London, said the condition was “well within the limits” of what the NHS could deal with.

So how will the winter of 2025 really be different and which patients are most affected by what the NHS is now describing as a “super flu”?

The biggest difference between the 2025 flu season and the previous three years is that the virus started spreading about a month earlier.

The first sign of this was seen in data published by the United Kingdom Health Security Agency (UKHSA) in October.

When someone goes to a GP or hospital with flu-like symptoms, they may be tested for a variety of viruses such as flu, Covid and RSV.

The UKHSA records the percentage of tests that come back positive for flu, which can give a strong indication of whether rates in the community are rising or falling.

Virologists attributed the flu season earlier this year to a slight shift in the genetic structure of the main circulating flu virus called H3N2.

The so-called ‘super flu’ is not a medical term and does not mean that the virus is more severe or harder to treat.

However, the public had not encountered this version of the flu before; This may mean that there is less immunity in the population, allowing it to spread more easily.

Children tend to be more susceptible to the flu than older adults; This is partly because their immune systems are still developing and they tend to spread viruses more quickly through close contact.

The latest breakdown of UKHSA data shows that the rate of positive tests is now much higher in children and young people still at school or university.

Some schools have had to bring back Covid-like measures, such as reducing singing at assemblies and installing cleaning stations, to prevent the spread of the virus. While a facility in Caerphilly was forced to close temporarily.

Every year, thousands of otherwise healthy children are admitted to the emergency room with complications after contracting the flu.

But there is another concern: Young people will go home and then spread the disease to their older relatives, who are more vulnerable.

The NHS records the number of patients hospitalized with flu and other respiratory illnesses each week.

In the UK this number is rising sharply; There were an average of 2,660 flu patients in a hospital bed last week. This figure was 1,717 the previous week.

People over 85 are five times more likely to be hospitalized than the general population.

But the patients now admitted would have contracted the virus a week or so ago, when infection rates were lower.

The biggest worry for the health service is what will happen as new cases emerge in A&E in the coming weeks.

The NHS has around 105,000 available hospital beds in England, which tend to be ‘hot’ throughout the winter, with 95% of them occupied at any given time.

If the number of flu patients needing night treatment rises to 5,000 or more, as Sir Jim Mackey predicts, this could put the entire hospital system under further pressure.

The message from doctors and the NHS is that people in vulnerable groups should continue to come forward for a flu jab.

Although the genetic structure of the virus has changed this winter, the main vaccine is thought to provide effective protection, especially against serious diseases.

The flu vaccine is free on the NHS for people over 65, young children, pregnant women, those with certain health conditions, carers and frontline health and social care workers.

People in other groups can get the same vaccine from high street pharmacists for between £15 and £25.

As of November 30, nearly 70% of seniors and care home residents accepted the offer of a free flu vaccine.

But in younger at-risk groups, such as the clinically vulnerable, vaccination rates were just over 40%.

Rates among NHS workers in England, which have fallen since the Covid outbreak, appear to have stabilized at around the same level this year, at around 42%.