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Page last updated on 21 February 2019

Seasonal influenza, also known as the flu, is an extremely contagious respiratory illness. In 2017, there were 250,144 (laboratory confirmed) cases in Australia, which was the largest since the 2009 pandemic year.

There are three main types of flu virus: the A, B, and C strain. The A and B strains cause most influenza in Australia. Each year the strains circulating are different. In some years, one of the A strains may be more common, while in other years, the B strains may be more common.

The flu is generally spread by coming in contact with an infected person. As a healthy person can begin infecting others from as early as 1 day before symptoms develop, and up to 5-7 days after becoming sick, it can be difficult to control the spread of the virus.

If you are infected with the flu you can spread it to people up to 6 feet away.

Vaccination is one of the best ways to protect yourself against the flu and other complications associated with the flu, including pneumonia.

Key disease information

Do I have the flu, or is it a cold?

Influenza are a group of viruses (classified as strain A, B or C) that are responsible for the disease we commonly call the ‘flu’.

It is a disease that is spread from person to person during coughing or sneezing or by direct contact with respiratory secretions (e.g. saliva, nasal discharge). It can cause a wide range of disease, from mild to more severe disease that affects many body systems and can result in hospitalisation, other infections (e.g. pneumonia) and even death.

The common cold is also caused by a virus, and also affects the airways, but generally tends to be milder than the flu. Colds do not usually cause serious complications or require hospitalisation.

So is it a cold or the flu? Often testing is required to know for sure, but here are some general ways you can distinguish some of the symptoms:

Sign/symptom Influenza Cold
Symptom onset     Abrupt Gradual
Fever Usual Rare
Aches Usual Slight
Chills Fairly common Uncommon
Fatigue /weakness Usual Sometimes
Sneezing Sometimes Common
Stuffy nose Sometimes Common
Sore throat Sometimes Common
Chest discomfort, cough Common Mild to moderate
Headache Common Rare

Adapted from the Center for Disease Control and Prevention (CDC).


How effective is the flu vaccine?

Each year, the flu vaccine effectiveness can vary – and it will depend on your age and other conditions and risk factors. It can also depend on the specific strains of influenza circulating in your community – the more closely they match the strains in the vaccine, the higher the effectiveness is expected to be. 

It takes between 5 – 6 months to manufacture a next year’s influenza vaccine. 

Each year the World Health Organisation (WHO), along with a specific team of collaborating researches, makes recommendations on which virus strains the influenza vaccine should cover for the following year. Once the vaccine strains have been decided, WHO then prepare the virus for use in manufacturing the vaccine. Once the vaccine has been tested to ensure it will protect against the specified strain, is safe and grows in eggs, it is then tested one last time and then sent to vaccine manufactures for mass creation. 

If you are unsure if the flu vaccine is suitable for you or your family speak with your health care professional for personalised advice.


Can I catch the flu from the vaccine?

No, and this is a common myth.

The flu vaccine cannot cause influenza as they are made from dead (inactivated) viruses. 

In some rarer situation people can develop some mild side effects associated with the flu vaccine. These include: 

  • Soreness, redness or swelling at the site of the injection
  • Fever
  • Aches
Why do I need to get vaccinated against the flu each year?

Each year, the influenza virus changes. Therefore, the vaccine that was made to combat last year’s strains are no longer effective (or as effective) against the current year’s strains. 

The way current flu vaccines work, the body’s immune response to the flu vaccine reduces over time, so annual vaccination is required to ensure you have optimal protection.

Is it safe for me to get the flu shot if I’m pregnant?

Yes. The influenza vaccine can be given at any time during pregnancy. 

In fact, vaccination is recommended for pregnant women in every pregnancy due to the risks associated with contracting influenza while pregnant. The risk of complications from influenza increase during the later stages of pregnancy along with the risk of premature delivery. 

The timing of the vaccination should be as early as possible during the pregnancy, taking into consideration the flu season and availability of the vaccine.

When is the best time to get the flu vaccine?

Influenza season in Australia usually peaks in August or September each year. Optimal protection from influenza vaccination occurs in the first 3-4 months following vaccination.

Therefore it is recommended to vaccinate when the national program starts, which is generally in late April. However as influenza continues to circulate, it is never too late to vaccinate.

If you are travelling to the northern hemisphere throughout their peak flu season, you should speak to your health professional about additional vaccination options.

Remember that it is always important to speak with your doctor about Influenza vaccination for you and your family.

Is the flu vaccine free?

Influenza vaccine is recommended for everyone > 6 months old.

It is currently free for the following groups of people due to their increased risk of complications from influenza:

  • Aboriginal or Torres Strait Islanders from 6 months of age
  • All adults > 65 years of age
  • All people > 6 months of age with certain medical conditions (e.g. severe asthma, lung or heart disease, low immunity or diabetes) – speak to your doctor if you are unsure if you are eligible
  • Pregnant women (at any stage during their pregnancy).
  • In 2018 most State & Territory governments are funding free flu vaccine for children less than 5 years of age.  

Check with your doctor for more information. 12-17

VaccineHub offers general information only. Please see a healthcare professional for medical advice

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Sources & Citations

  1. National Notifiable Disease Surveillance System. Number of notifications of Influenza (laboratory confirmed), Australia, in the period of 1991 to 2017 and year-to-date notifications for 2018. Available at: (accessed 23 April 2018) .
  2. Australian Government, Department of Health. Australian Technical Advisory Group on Immunisation (ATAGI) for immunization providers regarding the administration of seasonal influenza vaccines in 2017. Available at: (accessed 4 February 2018).
  3. Australian Government, Department of Health. The Australian Immunisation Handbook 10th Edition. Influenza. Available at: (accessed 16 April 2018).
  4. Centers for Disease Control. How Flu Spreads. Available at: (accessed 23 April 2018).  
  5. Centers for Disease Control. Cold versus flu. Available at: (accessed 16 April 2018).
  6. Centers for Disease Control. Key facts about seasonal flu vaccine. Available at: (accessed 16 April 2018).
  7. World Health Organisation, Pandemic influenza vaccine manufacturing process and timeline. Available at: (accessed 23 April 2018).
  8. Centers for Disease Control and Prevention. Pregnant women & influenza (flu). Available at: (accessed 20 May 2018).
  9. Cheng A and Macartney K. Flu vaccine won’t make you completely immune, but it’s more important than you think. The Conversation, 12 April 2017. Available at: (accessed 4 February 2018).
  10. Centers for Disease Control and Prevention. Misconceptions about flu vaccines. Available at: (accessed 4 February 2018).
  11. Australian Government, Department of Health. Australian Technical Advisory Group on Immunisation (ATAGI) for immunisation providers regarding the administration of seasonal influenza vaccines in 2018. Available at: (accessed 16 February 2018).
  12. NSW Government. Free flu job for NSW kids under five this winter. 23 January 2018. Available at: (accessed 7 July 2018).
  13. Queensland Government. Queensland Health. Free influenza vaccine for children. 20 October 2017. Available at: (accessed 7 July 2018).
  14. Government of Western Australia. Department of Health. Influenza immunization program. Available at: (accessed 4 February 2018).
  15. ACT Government. Free flu vaccinations for Canberra children this winter. 27 February 2018. Available at: (accessed 7 July 2018).
  16. SA Health. Free influenza (flu) vaccine for South Australian children under five. 27 April 2018. Available at: (accessed 7 July 2018).
  17. Hennessy J. Free flu vaccinations to protect Victorian kids. 24 February 2018. Available at: (accessed 7 July 2018).
  18. NSW Government. Health. Influenza factsheet. Available at: (accessed 20 May 2018).

SPANZ.IFLU.18.04.0165(1) - Date of preparation May 2018