Diphtheria alert for regional WA

Issued by: Director of Communicable Disease Control Directorate, Dr Paul Armstrong

An outbreak of diphtheria has been identified in regional Western Australia (WA) since late December 2025, mainly affecting Aboriginal people in the Kimberley region. A small number of cases have also been reported in the Pilbara and Goldfields regions. The risk to the broader WA community is currently considered to be low.

Diphtheria is a serious infection of the throat or skin caused by Corynebacterium diphtheriae (or less commonly Corynebacterium ulcerans) bacteria. Some strains of the bacteria produce a toxin (poison) that can cause severe illness and may be life-threatening. 

WA Health is working closely with Aboriginal health services and other clinical services to manage the outbreak and reduce spread:

• identifying and supporting people with diphtheria
• contract tracing to help stop spread
• supporting clinics and healthcare workers with advice and resources
• sharing information with communities about symptoms, prevention and when to seek care
• ·offering free diphtheria vaccination in the affected regions

Diphtheria was previously very rare in Australia due to high vaccination rates and improved living conditions – respiratory diphtheria had not been seen in WA for more than 50 years.

Cases have recently re-emerged in parts of Australia, including Western Australia.

The Northern Territory and South Australia are also experiencing outbreaks of diphtheria – see the Diphtheria in Australia – epidemiological updates from the Australian Centre for Disease Control for numbers of diphtheria cases reported in other Australian states and territories.

Diphtheria vaccines provide the best protection against severe disease.

Signs and symptoms of diphtheria

Symptoms usually appear two to five days after exposure (range one to 10 days). Diphtheria can affect the throat or the skin.

Respiratory (throat) diphtheria

• Often starts like a cold with sore throat, fever and chills
• Can cause a thick greyish-white coating in the back of the nose or throat
• May cause swollen, painful glands in the neck
• Can worsen, making it difficult to breathe or swallow
• Can become life-threatening.

Cutaneous (skin) diphtheria

• Can start from a cut or wound that becomes infected
• Usually appears as sores or ulcers that may be slow to heal, often on the legs
• May be covered with a grey, moist scab
• Is usually less severe but can still spread to others.

Complications are uncommon; they mainly occur in severe respiratory (throat) diphtheria and are caused by the toxin (poison) produced by the bacteria. They can include heart inflammation, nerve damage causing weakness or paralysis, or kidney damage.

In severe cases, paralysis can affect the diaphragm (breathing muscle), leading to pneumonia or severe breathing problems (respiratory failure). Around 5-10% of severe cases are fatal, even with treatment.

How is diphtheria spread?

• Diphtheria spreads through close contact with an infected person:
• breathing in droplets from coughing or sneezing
• direct contact with saliva, respiratory secretions, or infected skin sores
• contact with contaminated items such as bandages, towels or utensils.

People with diphtheria can spread the infection from shortly before symptoms start until they have been treated with antibiotics.

Who is at risk of diphtheria?

Most cases in the current outbreak have been reported in children and young adults, with smaller numbers of cases spread across older age groups.

• People at higher risk of diphtheria include:
• people who are not vaccinated or not fully vaccinated
• close contacts of someone with diphtheria
• people living in crowded settings where infections can spread more easily
• travellers to countries where diphtheria is more common
• young children and people with weakened immune systems (higher risk of severe illness if infected).

What to do if you develop symptoms of diphtheria

If you live in, or have recently travelled to, the Kimberley, Pilbara or Goldfields regions, or have had contact with a case of diphtheria:

• see a doctor as soon as possible if you have a sore throat, or skin sores that are not healing
• seek urgent medical care if you have a sore throat with fever and difficulty breathing or swallowing
• call ahead before going to a clinic or hospital so they can take appropriate precautions, wear a mask if you have throat symptoms, and cover any skin sores.

Diphtheria is confirmed by testing a swab from the throat or skin sore in a laboratory.

For advice, call Healthdirect Australia on 1800 022 222.

How is diphtheria treated?

Diphtheria infection is treated with antibiotics – some people may need care in a hospital.

Severe cases may need antitoxin to stop the toxin (poison) from causing further damage. Some people may require breathing support, including a breathing tube.

Skin infections may need regular wound care and dressings until sores or ulcers are healed.

How can diphtheria be prevented?

Vaccination is the most effective protection against diphtheria. Ensuring you and your family are up-to-date with vaccinations, including booster doses for teenagers and adults, is key to preventing severe illness.

You can also reduce the risk of infection and help prevent spread to others by:

• covering your mouth and nose when coughing or sneezing
• throwing away used tissues in the bin
• washing hands regularly with soap and water, especially before preparing food, after coughing or sneezing, and before and after touching skin sores or dressings
• keeping sores and wounds clean and covered
• getting skin conditions like ringworm (tinea), eczema and scabies treated early – healthy skin helps prevent infection
• avoiding close contact with people who are unwell
• staying home if unwell and limiting contact with others.

Are vaccines free?

Combined diphtheria, tetanus and pertussis vaccines (DTpa or dTpa) are free of charge across the state under the National Immunisation Program:

• infancy and early childhood: at six weeks, four, six and 18 months, and four years
• adolescence: in year seven of school, typically between 12 and 13 years of age (up to 20 years)
• pregnancy: ideally between 20- and 32-weeks’ gestation in each pregnancy.

In response to the outbreak, state-funded diphtheria vaccines are now available to more people. You can get a booster if you have not had one in the last five years and:

• reside in the Kimberley, Pilbara or Goldfields regions
• have regular face-to-face contact with Aboriginal communities in the Kimberley, Pilbara or Goldfields regions – this may include patient-facing healthcare workers and other frontline workers who work (but do not reside) in these regions.

In addition, children and adolescents in these regions eligible for vaccines funded under the National Immunisation Program, including school-based programs, who are not up to date with their scheduled diphtheria-containing vaccines, should be followed up and offered vaccination.

What if I’m not eligible for a free vaccine?

Booster doses of diphtheria-containing vaccines are generally recommended every 10 years, particularly in those aged 50 years and over. These can be discussed with your usual healthcare provider and are typically accessed via private prescription. An out-of-pocket cost for both the vaccine and consultation fee may apply.

Where can I get vaccinated?

State-funded vaccinations are available for free through GPs, community pharmacies, community health clinics and Aboriginal Medical Services in the Kimberley, Pilbara and Goldfields regions. An administration fee may apply.

National Immunisation Program vaccines remain available free of charge across the state.

Where can I find more information?

For more information about diphtheria, visit HealthyWA or speak with your healthcare provider.