Australia is contending with a significant outbreak of diphtheria, with the spread primarily noted in the Northern Territory and additionally in Western Australia, South Australia, and Queensland. Since March 2025, the Northern Territory declared an official outbreak. The surge began in late 2025, culminating in 245 cases by early 2026, making it the largest outbreak since 1991, affecting mainly remote Indigenous communities. The first confirmed death occurred in April 2026 at the Royal Darwin Hospital, following an autopsy confirming diphtheria as the cause. Prior to this incident, no deaths from diphtheria had been reported in Australia since 2018, highlighting the resurgence concern regarding this vaccine-preventable disease. In response, health officials have prioritized vaccination efforts in high-risk areas, with 10,407 vaccinations recorded by the end of March 2026, aiming to curtail the rising infection rates. As a preventive measure, both respiratory and cutaneous forms of diphtheria require vaccination, which consists of a series of doses given to children and a booster shot for older age groups. The respiratory variant of diphtheria can lead to severe symptoms such as fever, chills, and potential breathing difficulties, while the cutaneous type manifests as slow-healing sores. Health authorities are stressing the urgency for communities, particularly among teenagers and adults, to get updated vaccinations as health officials have observed a drop in new case numbers in recent weeks. The outbreak's management has seen a significant allocation of resources, with a AU$7.2 million funding package announced to bolster vaccination and health services in affected regions.