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What is flu?

Flu or influenza is an infection caused by the influenza virus which is passed from one person to the next in the air or by direct contact. Flu infects the throat, nose or lungs. The signs of influenza include the sudden onset of fever (> 37.8 °C), cough, runny or stuffy nose, headaches, muscle aches and often extreme fatigue. Flu symptoms may also be caused by infections other than influenza. True influenza infection only occurs during annual outbreaks (epidemics) at times when influenza viruses are spreading in the local community. Outside of the epidemic period, these symptoms will mainly be caused by a different type of infection or illness.

Differences between a common cold and Flu

A common cold is often mistaken for flu. Proper influenza can be very dangerous to people with asthma or similar lung problems, the elderly or the young so it's important to know the difference between influenza and a heavy cold or "man-flu".

Once you have had the proper flu, you will never again confuse it with a cold. Perhaps the most important thing in deciding if you could have the flu is to find out if the flu is going around in your community. If you suddenly start to feel unwell, call your doctor’s surgery and ask if the flu is currently prevalent in your area. Other clear indications of flu are:

  • Flu starts very suddenly whilst a cold will come on gradually
  • A cough is normally the first symptom of flu, with no stuffiness. A cold usually starts with a blocked or a runny nose or a sore throat
  • Influenza makes you feel unwell in your whole body, whilst a cold will only affect the nose, throat, sinuses and upper chest
  • If you have flu, you will feel dreadful, and you will have to go to bed. With a cold, you may feel unwell, but you can still carry on
  • Flu will normally last a week and leave you feeling tired for a further 10-14 days. A cold is normally over in 7 days.

Flu treatments

Effective treatments such as Tamiflu and Relenza are available to reduce the severity and length of an attack or prevent infection. They do not cure influenza or kill the influenza virus, but prevent the virus from multiplying. They are usually prescribed where there is a higher risk of developing complications from an infection, but they are not a substitute for an influenza vaccination.

Tamiflu Tamiflu Oseltamivir
Relenza Relenza Zanamivir