NHS staff who do not take a routine flu vaccine this winter are putting frail patients' lives at risk, a leading doctor has warned.
Despite a national campaign to improve uptake of the annual jab, more than half of frontline NHS workers did not get vaccinated last winter.
Dr Ben Marshall, a consultant respiratory physician at Southampton General Hospital, said the figure was "unacceptable".
"Influenza can be a troublesome infection for the average healthy person but it can be life-threatening for patients with chronic illnesses, immunodeficiency or frail conditions," he said.
"Therefore, it is really crucial staff across the NHS have the flu vaccine to protect themselves and their colleagues, who would take the brunt of their absence from work if they contracted flu but, more importantly, to protect their patients who might not be able to withstand the effects of the virus."
Uptake of the vaccine so far this winter has been higher than last year, with 35 per cent of all NHS frontline staff vaccinated in September and October - up from 28.4 per cent in the same time period last year.
Overall, 45.6 per cent of staff chose to have the vaccine during winter 2012/13.
Dean Royles, chief executive of NHS Employers, which has led national efforts to improve coverage, said that 5,000 staff had been vaccinated everyday so far this winter and predicted that record numbers of staff would be vaccinated this year.