As cases surge can Australia eliminate diphtheria again?

In 2026, Australia is experiencing the largest outbreak of diphtheria since records began in 1991, with 538 cases reported across the country. The majority of cases have been recorded in the Northern Territory, Western Australia, South Australia, and Queensland, surpassing previous peak years. Public health experts caution that the actual number of cases may be higher due to a drop in testing. The federal government has allocated $13 million to support affected jurisdictions in their response to the outbreak.

Diphtheria is a highly contagious and dangerous bacterial infection that primarily affects the nose, throat, airways, or skin. It is treated with antibiotics and vaccination is considered the primary defense against the disease. Most cases this year have been skin lesions, mainly affecting Aboriginal and Torres Strait Islander people in outer regional and remote areas. Experts note that waning immunity and poor housing conditions have contributed to the spread of the disease.

Professor Adrian Esterman from Adelaide University emphasizes that while skin lesion diphtheria is generally milder, it may go undetected or be misdiagnosed. Dr. Megan Campbell from the National Aboriginal Community Controlled Health Organisation warns that lower testing rates may be contributing to the apparent decrease in cases. She urges people in affected regions to get tested early if they have skin infections or sores or a sore throat.

CDC epidemiologist Stephanie Williams advises that while antibody levels generally decline over time, they still provide some protection. She stresses the importance of staying up-to-date with vaccinations and boosters. Experts agree that improving housing conditions and sanitation is crucial in preventing further outbreaks. While Australia has considered diphtheria largely eliminated since the 1950s, efforts must continue to address the complex factors contributing to this outbreak.