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Diphtheria is a severe inflammation of nose, throat and windpipe caused by the bacterium Corynebacterium diphtheriae

Page last updated 16 November 2023

The disease is rare in most developed countries including Australia due to routine vaccination. However, cases of diphtheria do still occur in Australia. In February 2018, in far North Queensland, a 20 year old man who was not vaccinated against the disease and had not travelled overseas, died due to complications.

Australia generally has high levels of protection against the disease, especially due to the inclusion of the vaccine on the National Immunisation Program (NIP). However, past outbreaks in other countries have been concentrated in poorly immunised, disadvantaged groups living in crowded conditions and low levels of immunity to diphtheria have been found in Australian adults.

Diphtheria vaccines are part of the NIP and they are provided free to infants, children and adolescents.

To find out more about diphtheria immunisation, speak with your healthcare professional.

Commonly asked questions

What is diphtheria?

Diphtheria is a bacterial disease that causes severe inflammation of the nose, throat and windpipe. 

The bacteria produce a toxin (poison) that attacks the lining of the back of the throat. The throat becomes inflamed and rapidly forms an abnormal membrane (barrier) over the back of the throat, which can make swallowing and breathing difficult. This alone can lead to suffocation.

The toxin can also spread throughout the bloodstream and affect other organs, including the heart and kidneys, as well as the nervous system. These complications can be fatal.

Vaccination is an effective way to prevent diphtheria.The disease is extremely rare in Australia due to ongoing routine vaccination programs.

How is diphtheria spread?

Diphtheria is spread from person-to-person by coughing or sneezing.

In Australia, it is now more common in adults rather than children – as most children have high levels of immunity due to immunisation programs. To prevent the spread of diphtheria, high levels of immunity are required in all age groups – which is why both adults and children are advised to be vaccinated against diphtheria.

In rare cases, the bacteria that cause diphtheria can cause a skin infection (called cutaneous diphtheria), and in these cases, the disease may spread by having contact with pus from the wound.

How severe is diphtheria?

Diphtheria can be life threatening if left untreated.  

The disease can escalate from its initial phase of sore throat, fever and loss of appetite to formation of an abnormal membrane in the throat within 2–3 days, which can cause severe weakness and death.

Rapid and effective treatment is important, however even with treatment, about 1 out of 10 people who contract diphtheria will die.

How is diphtheria prevented?

The most effective way to prevent diphtheria is by vaccination. 

Vaccination against diphtheria is part of the National Immunisation Program (NIP). The diphtheria vaccine is given at 2, 4 and 6 months of age along with tetanus and whooping cough vaccines, with boosters at 18 months, 4 years and 11-13 years of age. 



Because immunity acquired through vaccination against diphtheria wanes over time, older adults may no longer be immune. A diphtheria-containing vaccine booster is recommended for adults aged 50 years and over if their last dose was more than 10 years ago. Talk to your doctor about when a booster for diphtheria should be given.

Diphtheria can be a risk for travellers to some countries. Speak with your healthcare professional if you are planning to travel and they can advise whether you require a booster dose against diphtheria.

In addition to vaccination, the practice of good personal hygiene and isolation of patients will help decrease spread of the bacteria.


To find out more about diphtheria immunisation, speak with your healthcare professional.

How common is diphtheria now?

Due to routine vaccination diphtheria is now rare in Australia and other developed countries. However, in the cases that are reported diphtheria is now more commonly seen in adults than in children.

Although rare in Australia, diphtheria still occurs in many developing countries. In particular, Asia, the South Pacific, the Middle East, and in Haiti and the Dominican Republic. Outbreaks have occurred in Indonesia, Bangladesh, Myanmar, Vietnam, Venezuela, Haiti, South Africa and Yemen, since 2016.

If you are planning an overseas trip, make sure you are up-to-date with your immunisations.


Sources & Citations

  1. Victorian Government. Better Health Channel. Diphtheria. Available at: (accessed 24 November 2021).
  2. ABC News. Diphtheria death shows Queensland is failing to properly vaccinate, AMA warns. 8 February 2018. Available at: (accessed 24 November 2021).
  3. Australian Government Department of Health. Diphtheria in Australia, recent trends and future prevention strategies. Available at: (accessed 24 November 2021).
  4. Centers for Disease Control. Diphtheria. Symptoms. Available at: (accessed 24 November 2021).
  5. Centers for Disease Control. Chapter 4, travel-related infectious diseases. Diphtheria. Available at: (accessed 24 November 2021).
  6. Centers for Disease Control. Diphtheria. Diagnosis and Treatment. Available at: (accessed 24 November 2021).
  7. The Australian Immunisation Handbook. Diphtheria. Available at: (accessed 24 November 2021).
  8. Australian Government Department of Health. National Immunisation Program Schedule. Available at: (accessed 24 November 2021).
  9. Australian Institute of Health and Welfare. Diphtheria in Australia. Available at: (accessed 24 November 2021).
  10. World Health Organization. Immunization, Vaccines and Biologicals. Diphtheria. Available at: (accessed 24 November 2021)


MAT-AU-2102460  Date of preparation January 2022