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.
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.
Those who have any of the following conditions are entitled to receive the ‘flu jab:
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:
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.
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.
Those who are allergic to the vaccine.
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.
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
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.
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.
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.
Dr Nishan Wijenaike MD FRCP
Consultant Physician (Diabetes and Endocrinology)
West Suffolk Hospital NHS Trust
First published December 2005.
updated January 2009