Thousands of patients in England could be risking their health by not having the seasonal flu vaccine, according to figures released today by the Royal College of General Practitioners.

Compared with the same period last year over 6% fewer flu jabs have been given by GPs with some family doctors claiming their surgery fridges 'are full' of unused vaccines because patients are not turning up in the usual numbers.

They are worried that the uncharacteristically mild weather is deterring or delaying patients from having the jab, even though cold weather is not always a factor in flu outbreaks.

Of particular concern are those in 'at risk' groups such as older people, pregnant women, people with learning disabilities and those with long-term conditions such as asthma and diabetes who might not be getting their flu jabs.

The RCGP figures released today show that surgeries in England are vaccinating over 100 fewer patients per practice than this time last year.

The average (median) reduction in the number of flu vaccinations given per practice is 106 per practice fewer. Expressed another way GP practices are overall administering 2% fewer vaccines.

The weekly surveillance report produced by the RCGP, in conjunction with Public Health England, collects weekly data from over 100 GP practices across England to report disease 'trends' across primary care. The report is used by the Government and other health organisations to plan for outbreaks of particular diseases and was the main source of information used by health officials during the most recent flu pandemic in 2009.

Every year, GP practices determine from their practice lists how many vaccines will be needed and order their supplies accordingly. Patients who are eligible for the vaccination free on the NHS are contacted specifically by their GP surgery.

Patients can also get the flu jab from other health professionals such as pharmacists but the majority of NHS vaccinations for vulnerable groups are carried out in GP practices.

Professor Simon de Lusignan, Director of the RCGP Research and Surveillance Centre and a GP in Guildford, Surrey, said: "In my practice, we appear to be giving fewer vaccines and have now slowed the ordering of vaccines because our fridges are full.

"The College's 'surveillance' practices are seeing similar results. We took a snapshot of 101 practices and overall they reported an average (median) reduction of 106 fewer vaccines compared with the same period last year.

"The reasons for this are unclear, but it is possible that perceptions of lower vaccine effectiveness last year may have influenced people.

"However, the overall effectiveness of the vaccine last year was reasonable and patients are much better protected by having it. One of the reasons that we no longer experience the major flu outbreaks that we had during the 1960s and 1970s could be due to the flu vaccination policy so successfully delivered from general practice."

RCGP Chair and emergency planning expert Dr Maureen Baker said: "These figures are extremely alarming. We are experiencing an incredibly mild November this year but we don't need cold weather for a flu outbreak and influenza is a horrible illness that can also an trigger a host of other health problems.

"We urge patients not to shun the reminders they receive from the GP surgery and to have their vaccination as a priority. It provides valuable protection and plays a key role in keeping vulnerable people as healthy as possible through the winter.

"The drop in the number of vaccinations that we are seeing this year can only increase the risks for the frail elderly and others more susceptible to flu, as well as potentially increasing winter pressures on the NHS."