Diphtheria, a serious vaccine-preventable disease: first death in Australia in nearly 10 years

Diphtheria, a vaccine-preventable infectious disease, has returned to specialists' attention after Australia reported a death and a growing number of infections. Health authorities are warning that the infection is highly contagious and can cause serious complications, particularly in unvaccinated individuals.

Significant rise in cases

Australia is experiencing its largest diphtheria outbreak in decades, and authorities have confirmed the first death from the disease in nearly ten years. Case numbers began rising towards the end of 2025, with a notable acceleration recorded in the early months of the following year.

A total of 245 infections have been reported to date, the highest figure recorded in Australia since 1991. The majority of cases are occurring in remote communities, where access to healthcare services and vaccination is more difficult to ensure.

What is diphtheria

Diphtheria is a bacterial infection caused by the bacterium Corynebacterium diphtheriae. It spreads easily from person to person through droplets released when an infected individual coughs or sneezes, as well as through direct contact with infected wounds in the cutaneous form of the disease.

The disease can affect both the respiratory tract and the skin. The respiratory form is the most severe and can be life-threatening if not treated promptly. Common symptoms include fever, sore throat, difficulty swallowing, and the formation of a thick membrane in the throat, which can obstruct breathing.

Why it is considered a dangerous disease

Specialists explain that the bacterium produces a toxin capable of affecting several vital organs. Left untreated, diphtheria can lead to respiratory failure, heart damage, neurological disorders, and other severe complications that may prove fatal. For this reason, vaccination remains the most effective means of preventing the disease and its serious forms.

The most affected areas

The highest number of infections has been recorded in Australia's Northern Territory, a region accounting for approximately 60% of all confirmed cases. Between January 2025 and May 2026, 163 infected individuals were identified in this area: 48 with respiratory diphtheria and 115 with the cutaneous form of the disease, which affects the skin and is transmitted through contact with infected lesions.

In Western Australia, the first cases of respiratory diphtheria in over 50 years were confirmed in March. Further infections were reported in South Australia and, in smaller numbers, in the state of Queensland.

Intensified vaccination campaigns

In response to the rapid rise in infections, health authorities have launched extensive immunisation campaigns in the most affected regions. According to health officials, the measures taken have begun to yield results, with a gradual decline in new cases observed from May onwards.