Complications of Diabetes

The flu jab (influenza vaccine) and diabetes

What is the flu (influenza)?

Influenza, commonly referred to as ‘the flu’, is a viral infection characterised by rapid onset of fever, muscular pains and symptoms of chest infection, usually severe enough to confine the patient to bed for several days.

Chest infections are a common cause of hospitalisation in the elderly and account for about 1 in 5 deaths in people over the age of 65 years.

What are the symptoms of flu?

Influenza often presents with fever, chills, aches and pains. It may be accompanied by a variety of other symptoms such as headaches, sore throat, cough and runny nose. You may also have diarrhoea and vomiting, though these symptoms are more common in children.

We often refer to these symptoms as ‘flu-like’ symptoms. It is important to understand that having ‘flu-like’ symptoms does not always mean that you have the flu as many illnesses and even the common cold can produce the same symptoms.

Who should be considered for the flu jab?

Influenza vacineThose who have any of the following conditions are entitled to receive the ‘flu jab:

  • chronic chest conditions
  • chronic heart disease
  • chronic kidney disease or liver disease
  • diabetes
  • all people over 65 years – especially residents of nursing homes or residential homes
  • carers for sick family members and front-line health workers

What is the danger of contracting influenza if one has diabetes?

People with diabetes have greater susceptibility to infection. You may be more likely to develop complications of influenza such as pneumonia. Having an infection will also affect your blood sugar control. Your blood glucose levels may go high or low as a result.

Complications of influenza include:

  • Pneumonia
  • Dehydration and kidney failure
  • Heart failure
  • Diabetic emergencies

How do I contract the flu?

Influenza is passed on though contact and also by airborne ‘droplet’ infection which happens due to people coughing and sneezing. It is important to understand how the disease spreads. You may be able to pass on the infection even before you develop symptoms and upto a week after you contract the infection.

When should I have the flu jab?

Flu vaccine becomes available in October/November each year and it is designed to protect against the strains of flu virus anticipated that winter.

The ideal time to have the flu jab is late October/early November. Influenza virus tends to start circulating in the community towards the end of November. If you have the flu jab in late October, you should be protected by the middle of November as the antibody level may take a fortnight to rise.

We would still recommend that you have the vaccine even if the flu season has already started.

Who should not take influenza vaccine?

Those who are allergic to the vaccine.

What are the side effects?

The flu jab is usually well tolerated and it is generally regarded as a safe vaccine.

You may feel sore at the site of injection.

Some patients suffer aches and pains which may last up to 2-3 days.

Allergic reactions to the flu jab are rare.

What protection does vaccination give?

The influenza vaccine has been shown to reduce hospital admission and deaths from chest infections

Vaccination against influenza will protect against infection with influenza viruses A and B. These viruses adapt by continually altering their structure in order to outwit the host immune system

The World Health Organisation makes a recommendation each year as to which strain of influenza virus should be included in the current year.

Having the influenza vaccine will not protect you against the common cold or the other many viruses which cause chest infections

Can I catch influenza from having the vaccine?

Many people believe the vaccine can give you the flu. This is not true. The vaccine contains inactivated virus particles which cannot cause active infection.

How is the vaccine administered?

The vaccine is given as an intramuscular injection or deep subcutaneous injection. The injection is usually given to the upper arm into a muscle known as the deltoid.

I had the vaccine last year but still got the flu

This is possible. There are many strains of influenza and it is possible you may have contracted a virus which you may not have been protected against. There are also other causes of chest infections besides the flu.

What should I do if I get influenza?

  • Drink plenty of fluids. Avoid alcohol.
  • Take regular paracetamol
  • Bed rest
  • Monitor your blood sugars at least four times a day.
  • Inform your GP as you may be eligible for Tamiflu
  • Avoid contact with susceptible people. Keep away from work.


Dr Nishan Wijenaike MD FRCP
Consultant Physician (Diabetes and Endocrinology)
West Suffolk Hospital NHS Trust
First published December 2005.
updated January 2009