Influenza (Flu)

• 10-15% of the UK population are affected by flu each year
• 16,000 deaths were attributed to influenza in the winter of 1999
• Flu related illness accounts for 150 million lost working days
• An outbreak of flu across the country lasts 6-8 weeks

Influenza has three types of virus called A, B and C which affect the respiratory tract. Flu viruses mutate and change their surface structure which makes it difficult for the body's immune system to defend against them. When the immune system doesn't recognise the virus, epidemics and pandemics (widespread illness) occur, typically in the winter or spring.

Flu types A and B are more likely to result in an influenza epidemic. An epidemic occurs when the virus' structure develops a minor change making susceptible people vulnerable to infection (such as the elderly). Flu type A is the most serious and can happen every two or three years. Type A is more likely to result in a worldwide epidemic known as a 'pandemic'. This occurs after a major change to the virus' structure which affects a large number of people across regions and continents.

Flu type B is less severe and if previously infected with the virus, immunity against it can last a number of years. Type B flu virus mainly affects children who have not developed immunity. Flu types A and B usually occur in the winter months and can result in large numbers of people requiring hospitalisation (death may occur if other complications arise from the infection e.g. pneumonia).

Flu type C infections do not cause epidemics or have the same impact on health as types A and B. Type C infections often result in minor respiratory problems but can have no symptoms at all. Flu type C is more like the symptoms of a common cold. Controls on flu, such as the winter flu jab, concentrate on type A and type B infections.

Once infected with the flu virus, symptoms typically begin after one to three days. Once symptoms begin, they can develop rapidly.

Flu symptoms include:

·         Sudden fever (ranging from 38c to 40c / 100f to 104f. This can be even higher in children)

·         Cough

·         Sore throat

·         Stuffy nose

·         Excessive sweating

·         Headache

·         Sneezing

·         Fatigue

·         Aching muscles and joints

In infants and children, the following symptoms can also be present:

• Lack of interest in feeding
• Drowsy
• Non-responsive
• Lethargic (going limp)
• Nausea
• Vomiting
• Diarrhoea

People often refer to symptoms of influenza and the common cold as being the same and many of them are indeed similar. However, flu doesn't have the same bunged up heavy headed sensation as a cold and influenza affects the lungs more than a cold does.

Flu symptoms Versus Common Cold symptoms:

·         Symptoms of the flu can last for a week or more whereas cold symptoms pass after a few days.

·         High fever accompanies the flu; the cold usually just has a mild fever.

·         Shivers, muscle pain and joint pain often occur with the flu but not with a cold.

·         A cold will cause a runny nose whereas the flu begins with a dry nose and throat.

Most people will recover from the flu after one to two weeks however some people will develop life threatening illnesses such as pneumonia. The elderly, and people with chronic health problems, are the most vulnerable to influenza.

Most people can self-diagnose influenza from the symptoms they are experiencing. A GP will not be able to identify which type of virus you have been infected with and diagnostic tests will not be used unless your doctor feels there may be other complications to your health.

High risk groups, such as the elderly, are able to have a flu-vaccine each year to help them stave off infection.