Source: Radio New Zealand (world)
A century ago diphtheria was the biggest killer of children in New Zealand. Photo: AUBERT / BSIP / BSIP via AFP A disease which was once the biggest killer of children in New Zealand is having a resurgence in Australia.
ABC News is reporting more than 220 cases of diphtheria in 2026, primarily in the Northern Territory, but also in Western Australia, South Australia and Queensland.
The outbreak is the largest in decades, with the disease previously considered largely eradicated, and authorities are now waiting on confirmation of a reported death in the Northern Territory, which would be the first caused by diphtheria in almost a decade.
Professor of public health at Otago University Michael Baker explained diphtheria was a bacterial infection of the throat and skin – and nowadays, it was very rare. But a century ago, it was the biggest killer of children in New Zealand, he said.
In its respiratory form, the bacteria produced a severe toxin which damaged the heart, nerves and kidneys.
The other form, a chronic skin infection, caused ulcers on the skin. “What it used to do is circulate very widely in households, particularly where there is household crowding, and that’s probably what is driving this really remarkable outbreak in Australia at the moment,” Baker said.
Professor of public health at Otago University Michael Baker. Photo: High income countries generally had good vaccination against this disease. In New Zealand, the last case of respiratory diphtheria had been in 1998 – more than 25 years ago.
There had also been occasional skin infections, Baker said, but those were more easily managed and they too were rare.
Antibiotic treatment was effective – if received in time – and sometimes an anti-toxin was given to prevent damage caused by the bacteria. “It’s going to be very tough in Australia where they’ve got tens of cases occurring in quite remote communities, and so healthcare might be quite a long way off for these mainly children,” he said.
How worried should New Zealanders be?
With regular movement of people between Australia and New Zealand, the risk of importing cases was slightly elevated by this outbreak across the ditch, Baker said. “It does increase the concern for all countries in the region, but I don’t think it’s going to be a huge problem for New Zealand.” But, it was a reminder not to be complacent about vaccination “and our coverage levels actually are less than Australia for this vaccine”, he said.
According to Health NZ data, the percentage of fully vaccinated young children in New Zealand is in the mid-80s. In Australia, vaccination rates in children had been higher than 90 percent since 2000, according to the Australian government.
Anyone, of any age, could receive a booster, Baker said, as immunity warned over the course of a lifetime. A booster can cost between $40 and $90 depending on where you book, according to Te Whatu Ora.
Usually it is administered to babies, as part of a single vaccination against tetanus, whooping cough and polio.
Then, boosters were offered from the age of four – and anyone unsure of their vaccination status should get one, he said. “We can’t be complacent about these diseases,” Baker said. “Because they used to be huge killers, and they’ve largely disappeared because of high vaccine coverage, people are starting to think, ‘Oh, I don’t need to worry about that anymore’.
But actually, that’s not the case at all.” Symptoms of diphtheria, according to Te Whatu Ora Diphtheria can affect either the throat or the skin. Many people have no symptoms.
When diphtheria affects your throat it can cause: • thick, grey-white coating at the back of the throat which can block breathing and cause death • difficulty breathing • difficulty swallowing • throat and neck swelling caused by swollen glands known as a ‘bull neck’ If diphtheria affects your skin, it can cause: • pus-filled blisters on the skin • large ulcers surrounded by red, sore-looking skin Complications can include heart issues or failure, paralysis, kidney failure or death.
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