Flu circulated in the UK last winter, but with less mixing, fewer people caught it, meaning there is far less immunity than usual.
Under plans announced on Wednesday, around 33 million people in England will be eligible for a free flu shot this year, including all primary-aged children and some secondary-aged children, who will be offered the nasal spray
Around 26 million people in England are also eligible for the autumn COVID-19 booster shot, and those eligible for both could be offered both at the same time in different arms.
The UKHSA fears the effects of the predicted flu wave could be compounded by an increase in the transmission of the coronavirus as the nation moves into colder months.