Key points
1. Case numbers continue to rise from a large outbreak of diphtheria, primarily among Aboriginal and Torres Strait Islander peoples in Northern Territory and Western Australia.
2. Clinicians should consider diphtheria when a patient presents with a clinically compatible illness, especially if they have had direct or indirect contact with a remote Aboriginal community.
3. Vaccination is the most effective protection against diphtheria. Ensure all patients are up to date with vaccinations.
4. First Nations people 20 years and older in Queensland are now eligible for state funded dTpa vaccine (Boostrix) (see table).
5. Notify your local public health unit immediately of any suspected diphtheria cases.
Situation
From 1 January to 11 May 2026, 194 cases of diphtheria have been notified in Australia, markedly higher than in all previous years since national notification commenced in 1991. Of these:
- 69% were cutaneous infections, 30% were respiratory infections, and 1% reported with unknown clinical presentation.
- 117 cases were among residents of the Northern Territory, 71 in Western Australia, 4 in South Australia, and 2 in Queensland.
- 94% of cases were among Aboriginal and Torres Strait Islander people.
In Queensland, three sporadic cutaneous diphtheria cases have been notified in 2026, with the most recent case notified on 16 May 2026. Of these cases, one was acquired overseas, and two were linked to Western Australia; one case had no apparent epidemiological links to the current outbreak, while the other case reported travel to the outbreak area in the Kimberley region.
Clinical presentation
- Cutaneous diphtheria: Chronic, non-healing sores or shallow ulcers that can develop a greyish membrane.
- Respiratory diphtheria: Sore throat, low grade fever, pharyngeal exudate and a greyish white pseudomembrane overlying the tonsils, pharynx or nasal passages, enlarged anterior cervical lymph nodes and soft tissue oedema.
Testing and treatment
Seek specialist infectious disease advice on appropriate antibiotic therapy and the need for diphtheria antitoxin (DAT). Guidance is available on how to access DAT in Queensland via the Special Access Scheme.
Infection prevention and control measures:
- Ensure standard and droplet precautions are used when taking swabs for testing including a surgical mask, glasses, gloves and gown. Isolate suspected cases immediately.
Vaccination
- Available diphtheria-toxoid vaccines include dTpa, DTPa and dT vaccines.
- First Nations people 20 years and older in Queensland are now eligible for state funded dTpa vaccine (Boostrix).
Diphtheria-containing vaccination recommendations for Aboriginal and Torres Strait Islander people in QLD:
See the Australian Immunisation Handbook | Diphtheria for further information and recommendations for diphtheria vaccination in children, adolescents, pregnant people, and adults.
Further information
Fact sheet Diphtheria | Queensland Health
