Diphtheria factsheet


Diphtheria is a serious bacterial infection that happens in the nose and throat. The bacteria that cause diphtheria produce toxins that cause severe swelling and inflammation, as well as a grey-coloured membrane that grows over the throat. The membrane can stop your child from being able to breathe properly, causing death by suffocation.

Diphtheria is very serious but is also very rare in Australia because of the use of the diphtheria vaccine. There is a higher risk of getting diphtheria if you:

  • are not vaccinated against diphtheria
  • have a lowered immune system, like in cancer treatment
  • are living in a crowded or unhygienic environment
  • have travelled to regions where there is a known risk of diphtheria, like
    • Baltic states
    • Eastern Europe
    • Russia and surrounding countries
    • South-east Asia.

 Signs and symptoms

Diphtheria spreads through fluid droplets that are coughed or sneezed from an infected person. Symptoms usually show up 2-10 days after you have been infected with the bacteria.

Symptoms of diphtheria include:

  • runny nose
  • severe sore throat
  • fever
  • swollen glands in the neck and throat
  • a grey-coloured membrane growing inside the throat, sometimes covered in a furry, grey, or black coating made of bacteria
  • problems with breathing and swallowing that get worse over time.

Diphtheria can also cause an infection in the skin that causes inflammation, pus, pain, and a similar growth of grey and black fuzz to that found on the throat membrane.

Mild cases of diphtheria may not have many symptoms, but they will still be contagious for around 6 weeks.

Diphtheria is a serious infection, so take your child to your local doctor as soon as possible if they are showing symptoms or you are concerned.


Your child’s doctor will be able to diagnose diphtheria based on:

  • their vaccination record
  • travel history
  • a physical examination
  • swabs of the throat that are sent to be tested.


If your child’s doctor is confident that they have diphtheria, treatment will be started before results from any swabs come back.

Diphtheria is treated using antibiotics and anti-toxin to kill off the bacteria and toxins causing the infection and the growing membrane. Some children may need to be admitted to the hospital for treatment or surgery to remove the throat membrane.

Your child will need to be isolated while they are in treatment, which means they need to be separated from others in hospital and at home to stop the infection from spreading.

Parents and carers of a child with diphtheria will need to wash their hands before and after all contact with their child and may need to wear personal protective equipment (PPE) like masks, gowns, and gloves.

Anyone who shares a home with a child who has diphtheria will need to have a booster of the diphtheria vaccine and should have a course of antibiotics.


Diphtheria vaccine

Diphtheria can be prevented with the diphtheria vaccine. The diphtheria vaccine is made from a weak version of the toxin, which helps your child’s immune system to learn how to identify and attack diphtheria.

The diphtheria vaccine is included in the National Immunisation Program Schedule for children in Australia, which means the vaccination is free.

Children can get the vaccine at:

  • 2 months
  • 4 months
  • 6 months
  • 18 months
  • 4 years
  • 12-13 years through school vaccination programmes.

Side effects from these vaccines are uncommon and usually mild but may include:

  • pain and swelling where the needle was injected
  • a low temperature
  • feeling unsettled and sleepy.

Speak to your local doctor if you have any questions or concerns about the diphtheria vaccine.

Last updated Thursday 30th November 2023


This factsheet is provided for general information only. It does not constitute health advice and should not be used to diagnose or treat any health condition.

Please consult with your doctor or other health professional to make sure this information is right for you and/or your child.

The Sydney Children’s Hospitals Network does not accept responsibility for inaccuracies or omissions, the interpretation of the information, or for success or appropriateness of any treatment described in the factsheet.

© Sydney Children’s Hospitals Network 2024