By Michelle Roberts
Health reporter, BBC News
Eligible people are urged to get their free flu jab
Medical staff who do not get their flu jab are putting their patients in danger, say experts.
Seasonal flu is estimated to kill several thousand people, largely the sick and elderly, each year in the UK.
Official figures from the Health Protection Agency (HPA) show fewer than one in seven NHS staff in England went for their flu jab last winter.
It represents the lowest rate since monitoring began in 2001, with the worst offenders doctors and nurses.
In Scotland the uptake figure was just over one in five - a figure described as disappointing by officials.
New research published in the PLoS Medicine journal suggests that vaccinating seven health care workers would, on average, prevent one patient from getting influenza.
Researchers have also investigated why uptake is so low among health care workers.
Surveys show many staff do not think they need the vaccine because they are not sick.
And others are put off because they mistakenly believe the jab will give them flu or are worried about side effects.
Other staff say they simply "haven't got the time", or simply cannot be bothered to get vaccinated.
Professor Steve Field, chairman of the Royal College of General Practitioners, said: "It's very worrying. People - even doctors - have forgotten what flu is.
"They have not seen real, serious flu for years and are not getting their vaccine.
"It is putting patients at risk - not only from catching flu but from staff being off sick.
"Healthcare workers have a moral duty to get the vaccine."
He said GPs and NHS Direct had been seeing more people with flu symptoms and warned there could be a outbreak this Christmas.
Doctors are already being advised to prescribe antiviral drugs for flu in response to increasing numbers of people falling ill with the virus.
Professor John Oxford, a flu expert at St Bartholemew's and the Royal London Hospital, said: "All staff at all levels should be vaccinated to set an example.
"No one would like to infect one of their patients, but by not having a flu jab there is a risk."
He said it was technologically possible, using forensic microbiology, to look at a virus and determine which individual in all likelihood had passed it on to another.
If this "fingerprinting" of viruses became the norm it might spur staff on to get their jabs, he said.
Other countries have made it mandatory for healthcare workers to get their flu jab.
At least four US states have policies requiring influenza immunisation of workers in nursing homes and hospitals.
But similar policies do not exist in the UK, where healthcare workers who do not get their jab face no legal consequences.
ARE YOU ELIGIBLE?
Over the age of 65
Resident in a long-stay residential care home
Suffer from diabetes, chronic respiratory conditions or serious heart, kidney or liver disease
Undergoing cancer treatment
Have lower immunity due to HIV or medication, such as steroids
Have had a stroke
Health and social care professionals
According to the Medical Protection Society, an individual patient would face considerable problems if he or she decided to sue a healthcare worker for giving them flu.
This is partly because the vaccine used each year is a "best guess" and does not cover all strains of the virus.
The HPA said it was working to increase the number of immunised NHS staff.
A spokeswoman said: "We know the importance of vaccinating health care workers with the flu jab.
"Health care workers are an important group to target for the flu jab - both for their own health and to protect high risk patients."