Sir Jim Mackey, chief executive of NHS England, warned of a particularly severe flu season expected to coincide with the NHS recovering from a five-day strike by resident doctors.
The NHS is preparing for its most challenging winter yet, as an early flu outbreak is predicted to cause thousands of deaths, complicating recovery efforts and placing hospitals at full capacity from December through March.
The NHS has issued an urgent appeal for people to get vaccinated next week to ensure protection before the flu wave intensifies later this month.
Hospital admissions for flu in England rose sharply by 60% over the past week, increasing from 251 to 422. This level is typically seen only at the start of December.
Health officials noted the rise has occurred unusually early and warned many at risk may not realize they qualify for a vaccine, as only 28.9% of people with long-term health conditions have been vaccinated this year.
Recent analysis reveals flu deaths in England more than doubled last year, reaching 7,757 fatalities compared to 3,555 the previous year.
"The NHS is braced for its worst ever winter," Sir Jim Mackey said.
Summary: NHS England faces a critical winter with a severe early flu outbreak expected to strain hospitals post-doctors' strike, highlighting urgent vaccination needs amid rising flu deaths.