Influenza, commonly known as ‘the flu', is an illness caused by a group of viruses (the influenza viruses) that infect the respiratory tract. Influenza infection usually has different symptoms and causes a more severe illness than most other common viral respiratory infections and may be a life-threatening infection in certain people; it should not be confused with the common cold! 

In most parts of Australia, influenza outbreaks are seasonal, occurring between late autumn and early spring. Seasonal outbreaks occur every year and vary from mild sporadic outbreaks to serious epidemics; it is estimated that between 5 and 20% of the population may be infected annually. Occasionally severe worldwide outbreaks (pandemics) occur involving higher infection rates and more severe disease.

Influenza vaccines are available which offer a high degree of protection against seasonal illness and the severe consequences of influenza; however, these must be administered annually due to changes in the influenza viruses. Recently some effective antiviral medications for influenza have been developed, based on original Australian research, and these can be used to treat influenza infections provided that they are taken in the early stages of the illness.

• Fast facts - influenza
• Symptoms of influenza
• Spread of influenza
• Who is at risk?
• Eligibility for free flu vaccination
• Influenza in children
• Influenza viruses
• Impact of influenza
• Pandemic influenza
• Diabetes and Swine Influenza