What are the symptoms of flu (influenza)?

  • Fever (i.e. a temperature of 38.5°C or higher), and chills
  • Headache
  • Runny or blocked nose, and sneezing
  • Sore throat
  • Dry, chesty cough
  • Tiredness, aching muscles, and joint or limb pain
  • Loss of appetite, and upset stomach or diarrhoea.

How long will my flu symptoms last?

Your flu symptoms will usually be at their worst after 2–3 days and will generally last for 5–8 days. However, some of the symptoms of flu (e.g. a cough and tiredness) can last for about 2–3 weeks.

Most people who are generally healthy won’t need to see their doctor. Your immune system will fight your infection and your symptoms will usually clear up on their own.

You should try to rest, keep warm, drink plenty of water and non-alcoholic fluids, and manage your symptoms. This will help you recover and prevent dehydration.

For more information, read our page on how to manage the symptoms of flu.

See your doctor if you notice a change in your symptoms or they become worse.

Certain people have a higher risk of developing complications (e.g. pneumonia) from their flu infection and should visit their doctor when they become ill.

People at risk of infection and complications

The flu (influenza) can be a serious disease in some people, and its complications (e.g. pneumonia) can be life-threatening. Every year a number of people die from influenza and its complications.

People who are at risk of catching the flu or the complications of infection include:

  • children younger than 5 years old
  • people aged 65 years or older and older people living in residential nursing homes
  • people with heart or kidney disease, or a medical condition like type 2 diabetes
  • pregnant women
  • people who are very obese (Body Mass Index [BMI] of 35 or higher)
  • Aboriginal and Torres Strait Islander people
  • people with severe asthma, breathing problems or a lung disease (e.g. cystic fibrosis)
  • people with a disease affecting their muscles and/or the nerves that control them, and which can affect their ability to breathe (e.g. muscular dystrophy)
  • people with a weakened immune system (e.g. people with HIV, people taking medicines to suppress their immune system)
  • homeless people
  • people who smoke.
References
  • Respiratory Expert Group. Therapeutic guidelines: Respiratory – Influenza. Melbourne: Therapeutic Guidelines Ltd; March 2012. (Accessed 28 March 2012).
  • Rossi S, ed. eAMH [online]. Adelaide: Australian Medicines Handbook, July 2012.