Influenza (flu) is a contagious respiratory illness caused by influenza viruses. Most people recover after a few days but for some people it can be fatal. An influenza vaccination each year provides the best protection against influenza.
Influenza, or flu, is a highly contagious respiratory illness caused by influenza viruses. There are two main types of influenza virus that cause infection in humans - types A and B - and many sub-types or strains. Flu can occur throughout the year but influenza activity usually peaks in winter.
Flu is a vaccine-preventable illness but a new vaccine needs to be given each year because influenza viruses change (mutate) constantly. A new flu vaccine is prepared each year to best match the strains predicted for the coming flu season.
People with influenza typically experience some or all of the following symptoms:
Some symptoms may last for more than a week. Some people may also experience very mild symptoms, particularly if they have some immunity from a previous infection or vaccination.
Seek immediate medical advice if the illness quickly becomes worse or if any of the following symptoms occur:
Influenza viruses are mainly spread by droplets made when an infected person coughs or sneezes. Influenza can also be spread through touching surfaces where infected droplets have landed.
People with influenza can be infectious from the day before their symptoms start. Adults are most infectious in the first 3-5 days of their illness, while children remain infectious for 7-10 days, and people with weakened immune systems may be infectious for longer.
While anyone can get influenza, people at higher risk of complications from influenza infection (and who are eligible for free annual flu vaccine) include:
Individuals aged 6 months and over with certain medical conditions predisposing to severe influenza are also at increased risk (and also eligible for free annual influenza vaccine). These conditions include:
Influenza vaccination each year before winter arrives is the best way to prevent influenza.
For more information on general influenza vaccine recommendations refer to latest edition of The Australian Immunisation Handbook.
Sneeze into your elbow instead of your hands, or cover your face with a tissue when you cough or sneeze and throw used tissues in a rubbish bin.
Wash your hands thoroughly and often. Wash hands for at least 10 seconds, especially after coughing, sneezing or blowing your nose, or use an alcohol-based hand rub.
If you are sick with flu, stay at home and avoid close contact with other people to prevent them from also becoming sick. Keep sick children away from school and other activities. Wait at least 24 hours after fever resolves so you that you are unlikely to infect other people.
This is especially important if you visit people who are more likely to get really sick if they get the flu - including pregnant women, infants, older people or people in hospital or residential aged care. Similarly, if you think you may have influenza and you need to see a doctor, call ahead so the clinic can take precautions to reduce the risk to other people.
Doctors usually diagnose influenza based on symptoms. The diagnosis can be confirmed by testing a sample of fluid taken from the back of the nose and throat or a blood sample. These tests are usually only needed if the illness is severe or if there is an increased risk of complications.
The symptoms of influenza are usually managed by bed rest and taking simple analgesics for muscle aches and pains. Children under 16 years of age must not be given aspirin-containing medications while ill with influenza. This is due to the increased risk of children developing Reye syndrome, a form of encephalitis and liver degeneration.
Specific influenza antiviral medicines can reduce the severity and the duration of influenza but need to be taken within 48 hours of the first symptoms. These medicines need to be prescribed by a doctor, and are usually considered for people at higher risk of complications from influenza infection.
Laboratories must notify cases of influenza to their local public health unit. Individual cases are managed by their health care provider.
Public health action focuses on outbreaks in high-risk settings such as health care facilities, special schools, residential aged care facilities, and Aboriginal communities.
For further information please call your local public health unit on 1300 066 055.
