Twelve more people have died from confirmed flu in the past week, taking the death toll to 39, according to the latest UK figures.
Data from the Health Protection Agency (HPA) showed 39 people have died with flu since October, including 36 with swine flu and three with another strain, flu type B.
All except one case were under 65 years of age and four were under the age of five.
Today's figures come after it was announced yesterday that cases of flu rose by more than 40% last week.
The Royal College of General Practitioners (RCGP) reported that incidences of flu in England and Wales reached 124 per 100,000 of the population in the week ending December 26.
There were 86 per 100,000 cases in the previous week.
There has been a general increase across all age ranges apart from children, with the middle-aged being particularly badly hit.
Professor John Watson, head of the respiratory diseases department at the HPA, said: "We are seeing a large amount of flu circulating across the country and would urge those people in an at-risk group to have their seasonal flu vaccine as soon as possible as this is the best way to protect themselves from flu this winter.
"Anyone who has symptoms of flu-like illness should get medical advice as soon as possible and their GP will prescribe antivirals to reduce their symptoms and lessen the risk of them developing complications.
"Although there were reports of many people during the pandemic only experiencing mild disease we can't stress enough that flu can be an extremely serious illness for people in 'at risk' groups, including pregnant women, the elderly and those with other underlying conditions such as heart problems, diabetes, lung, liver or renal diseases and those who have weakened immune systems."