Kids Health Info

Influenza (the flu)

  • Influenza, commonly called the 'flu, is an infection caused by influenza A or B viruses. It mainly affects the nose, throat and lungs, although it can involve other parts of the body. In healthy children it is much like a bad cold, however influenza can cause more serious illness in very young children and those with chronic medical conditions.

    Influenza occurs mainly during the winter months. Each year infections are caused by slightly different strains of the virus. Occasionally one of these strains can cause a more widespread or severe outbreak, similar to the 2009 H1N1 (swine-flu) pandemic.

    Symptoms and signs

    Influenza usually begins with a sudden onset of fever and at least two or three of the following symptoms:

    • aches and pains
    • headache
    • cough or noisy breathing
    • sore throat and runny nose
    • low energy
    • nausea, vomiting and/or diarrhoea.

    Children at risk of severe illness

    Influenza can be more serious in children with chronic medical conditions including:

    • chronic respiratory conditions (including asthma)
    • chronic heart disease
    • chronic neurological or metabolic conditions
    • chronic kidney or liver problems
    • diabetes mellitus
    • a lowered immune system, due to medicines or illness.

    Warning signs of severe illness include poor feeding, dehydration and difficulty breathing.


    Most children recover within seven days without any treatment. Ensure your child has plenty of bed rest, encourage them to drink lots of fluids and use paracetamol for pain or discomfort. Do not give aspirin to your child if they have influenza as this can lead to serious side effects.

    Antibiotics are not helpful for influenza and will not be prescribed unless your child also has a bacterial infection. Antiviral medications (such as Tamiflu) are not given to children who have influenza and who are otherwise fit and healthy. This is because they do not usually make a difference to the duration of the illness.

    If your child has any warning signs of severe illness or is at risk of severe illness, seek urgent medical advice.

    How is it spread?

    Influenza is very infectious. It can spread through the air by coughing and sneezing and by touching objects that have been in contact with an infected person's mouth or nose. A person with influenza is contagious from the day before symptoms begin until a few days after.


    The best way to prevent influenza is the influenza vaccine (see below).

    Good hygiene habits can also reduce the chance of getting influenza or passing it to others.  These include:

    • regular hand washing
    • not sharing cups or cutlery
    • covering your mouth when you cough or sneeze.

    Influenza vaccine (the flu-shot)

    The influenza vaccine can be given to any child over six months of age to reduce the chance of becoming sick with influenza. Vaccination is voluntary, but vaccination is encouraged for everyone.

    If your child has a chronic medical condition, it is strongly recommended that they have an annual influenza vaccination. All household members should also be vaccinated to decrease the chances of your child being exposed to influenza. 

    Because the influenza virus changes (or mutates) slightly from year to year, your child will need a new and updated influenza vaccine at the beginning of each influenza season.

    Side effects of the vaccine include pain and redness at the site of injection. Less commonly, children may develop fever or aches and pains which last one to two days. The vaccine cannot cause influenza as it contains killed or inactivated influenza virus.

    While the current quadrivalent influenza vaccines (QIV) are made in egg embryos, there are now several published studies demonstrating the safety of influenza vaccines in egg allergic patients. Children with an egg allergy who would like to have the QIV should be referred to the RCH Immunisation service for vaccination.  For more information, call the RCH Immunisation service on (03) 9345 6599.

    Key points to remember

    • Vaccination is the best way to prevent influenza.
    • Influenza is very infectious so good hygiene is important.
    • Influenza is caused by a virus so antibiotics cannot be used to treat it.
    • Influenza can be more serious in children with chronic medical conditions.
    • Contact your family doctor if your child has influenza and has a chronic medical condition, or signs of severe illness.

    For more information

    • See your family doctor.
    • RCH Immunisation Service tel (03) 9345 6599.
    • Call Nurse-on-Call Tel 1300 60 60 24 (free call in Victoria).
    • Seasonal Flu factsheets from the Department of Health.
    • Kids Health Info factsheet: Fever in children.


    Developed by RCH General Medicine and Emergency Department. First published Aug 2007. Updated September 2017.

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This information is intended to support, not replace, discussion with your doctor or healthcare professionals. The authors of these consumer health information handouts have made a considerable effort to ensure the information is accurate, up to date and easy to understand. The Royal Children's Hospital, Melbourne accepts no responsibility for any inaccuracies, information perceived as misleading, or the success of any treatment regimen detailed in these handouts. Information contained in the handouts is updated regularly and therefore you should always check you are referring to the most recent version of the handout. The onus is on you, the user, to ensure that you have downloaded the most up-to-date version of a consumer health information handout.