Update on diphtheria outbreak, please keep vaccinating and remain vigilant.
There have been 389 notifications of diphtheria across Australia up to 22 June 2026, with 210 cases in the Northern Territory (NT), 167 in Western Australia (WA), 8 in South Australia and 4 in Queensland, 2 of whom have been linked with the WA outbreak. To date, 95% of cases have been reported among Aboriginal and Torres Strait Islander people and nearly all cases have occurred in residents of regional and remote locations.
A recent summary of the NT component of this outbreak Eurosurveillance | Diphtheria outbreak, Northern Territory of Australia, 2025 to 2026 identified several contributing factors including:
- Incomplete vaccination, too long since last booster
- Crowded and substandard housing
- High rates of skin infections
Preventing diphtheria through vaccination
With an imminent threat of impacts from the current outbreak, the best method of preventing diphtheria is vaccination. Three doses of diphtheria-containing vaccine in early childhood followed by booster doses at 18 months, 4 years and Year 7 of school and intervals throughout adulthood, are needed to produce and maintain immunity. Missing doses can be provided according to the table below, noting that First Nations people aged 20 years and older in Queensland are now eligible for state funded dTpa vaccine (Boostrix).
A collaborative response should also include strengthened healthy skin programs and longer term aims to improve housing and the broader determinants of health.
To improve vaccination coverage, especially among Aboriginal and Torres Strait Islander people, it is recommended to:
- Check your vaccination overdue notices and recall children who require catch-up Audit vaccination status of adult patients and recall for vaccination as indicated Opportunistically check patients are up to date with vaccination and provide dose/s as indicated.
Table: Current Diphtheria-containing vaccination recommendations for Aboriginal and Torres Strait Islander people in QLD: Update on diphtheria outbreak, please keep vaccinating and remain vigilant. v0.2 | 30/06/2026 | Central Queensland Public Health Unit Page 2 of 2
See the Australian Immunisation Handbook | Diphtheria for further information and recommendations for diphtheria vaccination in children, adolescents, pregnant people, and adults.
Diphtheria
Diphtheria is caused by toxin-producing strains of the germ Corynebacterium diphtheriae. Most Corynebacterium diphtheria germs are not toxin producing, and they can cause mild or asymptomatic skin or throat infections. However, toxin-producing germs can cause severe and life-threatening disease, especially in people who are unvaccinated or under vaccinated.
The germ is carried in the human nose and airway and the germ is spread person to person through respiratory droplets and through contact with infected skin or contaminated surfaces.
More information on diphtheria is available at:
https://www.health.qld.gov.au/disease-control/conditions/diphtheria
More information on the current diphtheria situation across Australia is available at:
https://www.cdc.gov.au/newsroom/news-and-articles/diphtheria-outbreak-update
https://www.cdc.gov.au/resources/collections/diphtheria-australia-epidemiological-updates
