The number of flu cases in hospital is seven times higher than last month, latest figures show.
New data from NHS England shows there were 3,746 patients a day in hospital with flu last week, up from 520 a month ago.
Of those in hospital last week, 267 were in critical care beds.
The NHS has warned the rise in flu cases is continuing to put pressure on health services.
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Bed occupancy remains particularly high, with more than nine in 10 beds filled (over 93%) compared to 86% for the same period last year.
The number of free beds was at the lowest seen since records began in 2012.
Professor Sir Stephen Powis, NHS national medical director, said: “Sadly, these latest flu numbers show our fears of a ‘twindemic’ have been realised, with cases up seven-fold in just a month and the continued impact of COVID hitting staff hard, with related absences up almost 50% on the end of November.”
Other areas have also been severely impacted.
The total number of NHS staff off sick is up a fifth on the end of November, from 52,556 to 63,296 a day.
Delayed discharges continue to take up hospital capacity, with 12,313 beds a day filled by patients who no longer met the criteria to reside, and nearly 600,000 calls were made to the 111 service – up more than two thirds from 365,338 this time last year.
“It is clear this is no time to be complacent and the risk of serious illness is very real, so with nearly 350,000 available vaccination appointments next week it is important that everyone eligible comes forward and gets their COVID and flu jabs at the earliest opportunity,” Prof Powis added.
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Responding to the latest NHS England report, the Royal College of Nursing (RCN) Director for England, Patricia Marquis said: “As we begin a new year, the NHS is buckling before our eyes. The pressures are immense with flu cases surging while staff absences rise dramatically.
“On top of this, the vast majority of adult general and acute hospital beds are full – around 94% – including tens of thousands of patients who are fit to be discharged but cannot be because of a severe lack of community and social care services.
“A key part of the problem is the record nursing vacancies across health and social care. But until nurses are paid fairly and appropriately, even more will leave the profession. The workforce crisis will get worse and patients will suffer.
“Ministers can begin to fix this by valuing the nursing profession properly and paying nurses fairly in order to retain and recruit the staff that patients need.”
Around this time last year (26 Dec 2021), there were only 34 patients in hospital with flu, two of whom were in critical care.