Australia is currently dealing with a significant increase in diphtheria cases, marking the country’s first death from the disease in almost ten years. The Northern Territory (NT) has been at the centre of this outbreak, which health authorities describe as the largest since 1991.
The diphtheria cases began rising in late 2025, with a notable surge early this year. As of now, there have been 245 reported infections nationwide, primarily affecting remote Indigenous communities across the NT, Western Australia (WA), South Australia, and Queensland.
In a recent update, the NT Health Minister Steve Edgington confirmed an autopsy from an overseas laboratory showed diphtheria was the cause of death of a man in April at the Royal Darwin Hospital. This is the first recorded diphtheria fatality in Australia since 2018.
The outbreak involves two forms of diphtheria: respiratory and cutaneous. Respiratory diphtheria, which can cause serious breathing and swallowing difficulties, is less common but carries a higher risk of severe illness. Cutaneous diphtheria presents as persistent skin sores often spread by contact and, while rarely life-threatening, contributes to wider transmission.
Within the NT, there have been 163 cases recorded from January last year through May of this year. Of these, 48 are respiratory and 115 are cutaneous cases. WA has reported two respiratory diphtheria cases this year, a development not seen in the region for over 50 years. Overall, approximately 60% of this year’s cases have occurred in the NT, with WA accounting for around 36%, and fewer cases in South Australia and Queensland.
The increase in cases has prompted accelerated vaccination efforts. Since late March, the government has delivered more than 10,400 vaccinations, focusing on vulnerable communities where immunity may have waned, especially among teenagers and adults who require booster doses.
To facilitate access to immunisation, pop-up clinics have been established in key locations such as Darwin, Katherine, and Alice Springs. Public health officials emphasise that vaccination remains the most effective way to prevent diphtheria infection and reduce its spread.
The diphtheria vaccine is typically administered to children in five doses between two months and four years of age, with a booster given between 12 and 13 years. Keeping up with these schedules is crucial for maintaining community protection.
Symptoms of respiratory diphtheria often include fever, chills, and a sore throat, potentially progressing to breathing and swallowing troubles requiring urgent medical attention. Cutaneous diphtheria shows as skin sores that heal slowly, creating a risk for ongoing transmission if left untreated.
Given the growing case numbers and recent fatality, Australia's Chief Medical Officer, Professor Michael Kidd, has classified diphtheria as a communicable disease incident of national significance. This designation underscores the urgency of containing the outbreak and protecting high-risk populations.
The federal government has committed a A$7.2 million package to enhance vaccination availability and health resources in affected areas. This response aims to limit further spread and prevent additional severe outcomes.
For residents in impacted regions, health officials recommend checking vaccination status and attending local clinics offering booster shots. Maintaining up-to-date immunisation not only protects individuals but helps safeguard whole communities from this largely preventable disease.
While the current diphtheria outbreak is the most serious in decades, ongoing vaccination campaigns and awareness efforts remain key to managing the situation. Close monitoring and prompt vaccination uptake will be critical in reducing the public health impact moving forward.
