A life-threatening bacterial disease that has not been detected in Western Australia for more than half a century is now spreading rapidly across regional parts of the state, pushing case numbers to alarming levels and prompting public health officials to issue an urgent plea for vaccination across all age groups.
In just five months, WA Health has confirmed 60 new diphtheria cases across the state. The vast majority of these infections have been recorded among Indigenous communities in the Kimberley region, with only a small handful of additional cases detected in the neighboring Pilbara and Goldfields areas. A spokesperson for the department noted that infections have been concentrated mostly among children and young adults, though a small share of cases have affected older age groups.
Diphtheria is a highly contagious bacterial infection that can cause severe, potentially fatal complications if left untreated. The disease spreads easily through multiple pathways: close contact with respiratory droplets from an infected person, direct contact with open, infected skin lesions, or exposure to contaminated objects such as used bandages and shared personal items like towels. There are two primary forms of the infection: respiratory diphtheria and cutaneous diphtheria.
Respiratory diphtheria, the more dangerous variant, typically starts with mild, flu-like symptoms including a sore throat, fever, and chills. As the infection progresses, it can develop a thick gray coating at the back of the throat that severely obstructs breathing and swallowing. Cutaneous diphtheria, by contrast, causes slow-healing open sores and ulcers on exposed areas of the body. While this form rarely causes severe systemic illness, health officials emphasize it plays a major role in spreading the bacteria to other people across communities.
Western Australia’s Chief Health Officer Dr. Clare Huppatz explained that diphtheria had been effectively eliminated in Australia for decades, thanks to widespread routine vaccination programs and improvements in public living conditions. Before this current surge, respiratory diphtheria had not been documented in Western Australia for more than 50 years, and even skin infections had become extremely rare. However, Dr. Huppatz noted that the disease has begun to reemerge across parts of northern Australia in recent years, with the neighboring Northern Territory also declaring a formal diphtheria outbreak in recent weeks.
The unexpected resurgence of the disease serves as a critical reminder that continued vaccination and booster doses are essential to maintain long-term population immunity, particularly for adolescents and adults, Dr. Huppatz said. Diphtheria vaccines are almost always administered in combination with vaccines for tetanus and pertussis (whooping cough), as part of standard national immunization schedules.
With cases concentrated in remote and regional communities, public health authorities are particularly focused on reaching people who live, work, or travel through these high-risk areas. Officials stress that all people in these regions should ensure their vaccinations are up to date. For those who have previously completed a primary vaccination course but have not had a booster in more than five years, a top-up dose is recommended — this guidance is especially urgent for Aboriginal and Torres Strait Islander people living in affected regions, as well as local healthcare workers, who face a higher risk of exposure to the bacteria.
Individuals who are unvaccinated against diphtheria, or who cannot confirm their vaccination status, are advised to contact their general practitioner or local health provider immediately to begin a recommended vaccination series. Officials also issued a direct reminder to parents and caregivers to ensure their children receive all routine childhood diphtheria vaccinations on schedule, including all recommended booster doses, to protect them from infection early in life.