Daijiworld Media Network – Sydney
Sydney, May 20: Australia’s top medical body has urged citizens to ensure they are fully vaccinated against diphtheria as the country faces what authorities describe as its biggest outbreak of the disease in decades.
The Australian Medical Association (AMA) on Tuesday called on families across the country to check their vaccination and booster status following a sharp rise in cases of the highly contagious bacterial infection.
According to health authorities, a total of 223 confirmed diphtheria cases have been recorded so far, with the outbreak spreading across the Northern Territory, Western Australia, Queensland and South Australia.
One person has died in the Northern Territory, although officials said the exact cause of death is still under investigation.
The current outbreak reportedly began in remote Aboriginal communities in the Northern Territory before spreading across all five regions of the Territory and into neighbouring states.
Health authorities said genomic sequencing linked the present strain to smaller outbreaks previously reported in Western Australia’s Kimberley region and North Queensland during 2024 and 2025.
The Northern Territory has recorded 133 cases so far, while Western Australia has reported 79 cases. Queensland and South Australia have confirmed five and six cases respectively.
“This is probably the biggest diphtheria outbreak we’ve seen certainly for decades,” Australian Health Minister Mark Butler said, describing the situation as serious.
Officials noted that almost all current cases in the Northern Territory involve Indigenous Australians, prompting efforts to boost vaccination coverage in vulnerable communities in collaboration with Aboriginal-controlled health organisations.
AMA president Dr Danielle McMullen stressed the importance of immunisation, warning that declining vaccination rates could lead to the return of dangerous diseases once considered nearly eradicated.
“Immunisation is one of the greatest achievements in modern medicine, but when vaccination rates fall, serious diseases which we had largely eliminated can make a comeback,” she said.
Health experts believe falling childhood vaccination rates globally following the COVID-19 pandemic may be contributing to the resurgence.
Australia’s childhood vaccination coverage has gradually declined since peaking in early 2020. In 2024, the percentage of fully vaccinated two-year-old children reportedly fell below the critical 90 per cent threshold.
By the end of last year, only 79.7 per cent of babies received their diphtheria vaccine doses on schedule, nearly doubling the number of children who were either unvaccinated or vaccinated late compared to early 2020 figures.
Diphtheria, once one of Australia’s leading causes of child mortality, killed more than 4,000 Australians between 1926 and 1935 before widespread immunisation campaigns drastically reduced cases by the 1950s.
The disease is caused by toxins produced by Corynebacterium bacteria and spreads through respiratory droplets from coughing or sneezing, as well as through infected skin sores.
Early symptoms resemble common flu or cold symptoms, including fever and sore throat. In severe respiratory cases, a grey-white membrane can form in the throat, making breathing and swallowing difficult.
Doctors warned that severe infections may cause swelling in the throat and neck, leading to airway blockage, breathing failure and death. The toxin can also damage the heart, kidneys, nerves and brain.
Health experts emphasised that vaccination remains the most effective protection against diphtheria, while prompt antibiotic treatment and antitoxin therapy are critical once infection occurs.
Even with treatment, authorities said up to one in ten patients suffering from severe respiratory diphtheria may die.