Diphtheria outbreaks in Northern Territory and Western Australia, 2026
Consensus Summary
In 2026, Australia is experiencing rare diphtheria outbreaks in the Northern Territory and Western Australia, with cases surging in both regions. The Northern Territory reported 18 confirmed respiratory diphtheria cases and 66 cutaneous cases since 2025, primarily affecting Aboriginal and Torres Strait Islander communities across all five regions, including remote areas. Western Australia recorded 60 cases in five months, concentrated in the Kimberley among Indigenous Australians. Both outbreaks have been linked to interstate spread, with previous cases in North Queensland and the Kimberley. Health authorities in both states emphasize the importance of vaccination, noting the disease is vaccine-preventable and can be deadly if untreated. The diphtheria vaccine is available as a combination shot with tetanus and pertussis, with booster doses recommended every 10 years for adults. Factors such as overcrowded housing, remoteness, and limited healthcare access are exacerbating transmission in affected communities.
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Key details reported by multiple sources:
- Diphtheria cases in the Northern Territory have risen to 18 confirmed respiratory diphtheria cases (up from 4 in late April 2026) and 66 cutaneous diphtheria notifications since 2025.
- Western Australia reported 60 diphtheria cases in five months (2026), primarily in Indigenous Australians in the Kimberley, with smaller numbers in the Pilbara and Goldfields.
- Respiratory diphtheria symptoms include sore throat, mild fever, loss of appetite, and in severe cases, trouble breathing; cutaneous diphtheria symptoms include sores or ulcers (often on legs) and slow-healing wounds.
- Diphtheria is caused by toxic strains of the bacterium *Corynebacterium diphtheriae*, and both respiratory and cutaneous strains are highly contagious and vaccine-preventable.
- The Northern Territory’s outbreak primarily impacts Aboriginal and Torres Strait Islander peoples, with 93% of confirmed cases among them, and cases are widespread across all five NT regions, including remote communities.
- The diphtheria vaccine in Australia is only available as a combination vaccine (including pertussis and tetanus), and booster doses are recommended every 10 years for adults.
- Diphtheria outbreaks in northern Australia have been linked to interstate spread, including previous outbreaks in North Queensland (2022–2024) and the Kimberley (2025).
Points of Difference
Details reported by only one source:
- The Northern Territory declared a diphtheria outbreak for the first time since the 1990s in April 2026.
- NT Health reported 33 cases of cutaneous diphtheria since 2025, alongside the 18 respiratory cases.
- NT Chief Health Officer Paul Burgess stated the outbreak likely arrived from interstate, citing outbreaks in North Queensland (2022–2024) and the Kimberley (2025).
- AMSANT (Peak Aboriginal health body) emphasized overcrowded housing, remoteness, and limited access to care as factors increasing transmission in the NT.
- The NT’s public health alert mentioned respiratory diphtheria had not been seen in the Territory for decades prior to 2026.
- WA Health stated that diphtheria cases in WA have primarily occurred in children and young adults, with a smaller number in older age groups.
- WA Chief Health Officer Dr Clare Huppatz noted respiratory diphtheria had not been seen in WA for over 50 years prior to the 2026 outbreak.
- WA Health recommended booster doses for those living in or traveling to affected regions if more than five years have passed since their last vaccination.
- WA Health highlighted that cutaneous diphtheria rarely leads to severe illness but contributes to community spread.
Contradictions
Conflicting information between sources:
- ABC states the NT’s respiratory diphtheria cases quadrupled from four to 18 in just over a month, while NEWSCOMAU does not provide a comparable timeline for WA’s 60 cases in five months.
- ABC reports 93% of NT cases are among Aboriginal and Torres Strait Islander peoples, while NEWSCOMAU does not specify a percentage for WA’s Indigenous cases but notes they are primarily affected.
Source Articles
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