Disease type: 
Vaccine funded under NIP

What is diphtheria?

Diphtheria is caused by the spread of a bacterium, Corynebacterium diphtheria. When a person catches diphtheria, the bacteria release a toxin, or poison, into the person's body. The toxin infects the upper airways, and sometimes the skin, causing a membrane to grow across the windpipe. This makes it hard to breathe and if the membrane completely blocks the windpipe can lead to suffocation and death. The heart and nervous system can also be damaged.


Diphtheria symptoms include:

  • sore throat
  • swallowing problems
  • mild fever
  • breathing problems, which may be severe
  • a grey or green membrane at the back of the throat.

Symptoms usually start about 2 to 5 days after catching diphtheria.

Who is at risk

Diphtheria can affect people at any age. People who haven’t been immunised have the highest risk of serious disease.

How it spreads

Diphtheria spreads:

  • when an infected person coughs or sneezes and you breathe it in
  • by direct contact with a wound infected with diphtheria
  • when you touch things an infected person has coughed or sneezed on.

If you have diphtheria, you can help stop the disease spreading by:

  • staying away from childcare, school, work or other places where you could spread the infection – your doctor will tell you when you’re no longer infectious
  • washing your hands often
  • covering your coughs and sneezes.


Vaccination is the best protection against diphtheria. In Australia, diphtheria and tetanus vaccines are combined. Since the vaccine was made available, diphtheria has almost disappeared. Vaccinating is still important because people can bring diphtheria into Australia from overseas.

Find out more about getting vaccinated against diphtheria.


Your doctor can diagnose diphtheria by:

  • examining your throat for a grey or green membrane
  • asking if you’ve been in contact with someone who has diphtheria
  • checking other symptoms – fever, breathing or swallowing problems
  • swabbing your throat – or your wound if you have a skin infection – to test for the bacteria.

If you have diphtheria your doctor may be required to notify your state or territory health department.


Diphtheria is treated with antibiotics and diphtheria anti-toxin. You may also need other medicines to help with the complications from diphtheria, such as heart problems.

Some people may need surgery to remove the grey or green membrane that can form in the throat. Isolating people with diphtheria may prevent the disease spreading.

Even with treatment, people sometimes die from diphtheria.

Last updated: 
16 February 2022