Health chiefs have urged vulnerable people to have seasonal flu jabs following a number of deaths from swine flu in the North West of England.
The virus contributed to the deaths of three men in Greater Manchester and a 32-year-old mother-of-two from Liverpool.
Kay Burdett, of Old Swan, died at Royal Liverpool Hospital last Friday.
She was reportedly discharged from the hospital earlier this month after spending three months there being treated for an asthma condition.
The other cases involved two men from Oldham - who both died in recent weeks - and a man from Rochdale. All three had underlying health conditions.
The Health Protection Agency wants pensioners, pregnant women and people with a long-term health condition to take up the free seasonal flu vaccine which this year includes protection against swine flu.
Diane Wake, Royal Liverpool Hospital's director of nursing and operations, said: "We can confirm the sad news that Kay Burdett has died and that Kay had H1N1 (commonly known as swine flu) and that this
was a contributory factor in her death.
"We would like to pass on our deepest sympathy to Kay's family and friends at this difficult time.
"As this tragic case highlights, a small number of people with flu, particularly those with chronic ill health, can become seriously ill and die.
"Most people with flu recover completely without any need to see a doctor.
"We would ask that the people of Merseyside with flu-like symptoms, do not come into our Emergency Department, visit patients or come in for routine appointments. We are happy to rearrange appointments. This will help protect our vulnerable patients.
"The Emergency Department gives the same medicines you can get from a pharmacist or a GP to those people who come in with flu-like symptoms."
Confirming the two Oldham deaths, the area's director of public health Alan Higgins, said:
"It is with regret that NHS Oldham confirms that two people from Oldham have died at the Royal Oldham Hospital, with swine flu as a part of the cause of death. The two men also had serious underlying illnesses."
Director of public health for the Rochdale borough, Dr Jane Rossini, said: "It is with regret that NHS Heywood, Middleton and Rochdale confirms that one person from the Rochdale borough has died at the Rochdale Infirmary, with swine flu as a part of the cause of death. He had other long term health issues.
"I am saddened by this event here in the borough.
"Can I urge people to take care of themselves - if you're eligible for a flu jab please make sure you have one."
In a joint statement, Dr Higgins and Dr Rossini said: "In terms of general advice, it is most important that people who are over 65 or have a long term condition have a flu jab to help keep them healthy over the winter.
"People who had a seasonal flu jab last year need to get a new jab this winter. This year's seasonal flu vaccine protects against three strains of flu that are circulating this winter, including H1N1
"Those at greater risk of developing serious complications from flu should contact their local GP practice as soon as possible to arrange a flu jab to protect themselves from the virus in the months to come."