Getting a flu shot may help ensure you're not one of the many thousands of people laid low by influenza during the colder months. No one enjoys being bedbound with the flu, but for some people the symptoms can be far worse than a few miserable days in the reclined position. In an average year it's estimated that 1500 Australians die and 20,000 to 40,000 are hospitalised as a result of the flu.

The influenza virus is constantly changing, so the flu vaccine changes every year to keep up with the most common strains.

  • Getting an annual flu shot is the single most important and effective measure in preventing the illness.
  • It's recommended that you get your flu shot in March or April.
  • The protection develops two weeks after getting the injection and lasts up to a year.

In this article:

The vaccine – what's in it and how it's made

  • The World Health Organization (WHO) has 100 national influenza centres worldwide and four collaborating centres (including one in Melbourne) which analyse viruses from around the world. WHO convenes two meetings each year, in February and September, to review the findings of the centres and recommend which vaccine formulations should be used in the northern and southern hemispheres respectively.
  • The vaccines currently used in most parts of the world are taken from an influenza virus that has been grown in embryonic hens' eggs, highly purified and then inactivated (killed).
  • The vaccine also contains salt water and trace amounts of an antibiotic.
  • The preservative thiomersol, which contains a form of mercury and which was widely used in the past, has now been removed from many vaccines available on the market in Australia. If you're at all concerned about this, check with your GP.
  • The vaccine is injected into the shoulder, or the thigh for children between six and 12 months.

Will I get sick?

As the influenza virus components in the vaccine have been killed, you won't get the flu as a result of having a flu shot, but some people experience some mild flu-like symptoms for a day or so afterwards.

Trivalent or quadrivalent?

For the Australian 2016 flu season, there are two vaccines available – trivalent and quadrivalent. The trivalent vaccine protects against three strains of virus:

  • A (H1N1): an A/California/7/2009 (H1N1)-like virus
  • A (H3N2): an A/Hong Kong/4801/2014 (H3N2)-like virus. H3N2 is generally the most severe form of influenza A.
  • B: a B/Brisbane/60/2008-like virus.

The quadrivalent vaccine protects against the above three strains, plus:

  • B/Phuket/3073/2013-like virus.

The virus strains included in the trivalent vaccine account for almost all cases of flu, and the quadrivalent vaccine offers little extra benefit – though the benefits may be greater for children. The government has chosen the quadrivalent vaccine for its free program for vulnerable people.

Who should get a flu vaccination?

Certain vulnerable groups are eligible for free vaccination as part of the National Immunisation Program:

  • All adults aged 65 and over.
  • Aboriginal and Torres Strait Islanders aged 6 months to 5 years, and 15 and over.
  • People older than six months who have diabetes, cancer, asthma, low immunity, chronic respiratory disorders or chronic heart, kidney or metabolic disorders.
  • Pregnant women.

But anyone who wants to avoid getting the flu should get a flu shot, and it's especially recommended for:

  • Public hospital outpatients and inpatients who are considered to be at high risk for complications of influenza.
  • Residents of nursing homes, care hostels and other chronic-care facilities.
  • Children with cyanotic congenital heart disease.
  • People such as doctors, nurses, daycare staff and nursing home staff who are in contact with at-risk groups.
  • Family members caring for elderly people and/or people with chronic health conditions listed above.
  • Children on long-term aspirin therapy.

Who shouldn't get a flu vaccination?

The only absolute contraindications to influenza vaccines are anaphylaxis following a previous dose of any influenza vaccine or any vaccine component.

Other groups for which caution is recommended include:

  • People with a severe allergy to eggs (the virus used in the vaccine is grown in hens' eggs). It's best administered in a setting with staff who can recognise and treat anaphylaxis.
  • People already ill with a fever — wait until your symptoms subside before being vaccinated.
  • People who have previously suffered from Guillain-Barre syndrome (GBS). In the 1990s, studies found an association between the vaccine and GBS in the northern hemisphere, at a rate of roughly one to two cases of GBS per million vaccinated. If you've suffered from GBS you should discuss vaccination with your doctor.
  • Babies under six months of age.

The government recommends children under 5 should not receive the Fluvax brand vaccine, as it's been linked with febrile convulsions. Children aged 5 to 9 may receive it only if the doctor considers the potential benefits outweigh the risks, but there are other brands available.

More information

There's more information about flu and vaccination on the Immunise Australia Program influenza web page, with more technical information available at the Australian Immunisation Handbook section on influenza.