Leaked data shows NT diphtheria surge pre-alert
Leaked Northern Territory Health data indicates diphtheria cases rose sharply weeks before a public alert was issued, providing the clearest timeline yet of how the country’s worst recorded outbreak since 1991 spread across the Territory.
Internal Northern Territory Health (NT Health) data circulated to service providers on Thursday — and confirmed as accurate by the department — shows a handful of diphtheria cases in early January. From the last week of February, multiple cases began to be recorded week on week across Darwin, the Top End and the Katherine region. Despite that trend, NT Health did not issue a public health alert pertaining to the outbreak until March 25.
Key Points
- Internal NT Health data shows cases surged weeks before public alert
- Multiple cases recorded weekly from late February across three regions
- Public alert issued March 25 despite January and February case growth
- NT confirmed one diphtheria death since the outbreak began
- Federal support request came in late-April, Mark Butler said
- Case numbers have fallen over the past three weeks, officials say
- Commonwealth announced $7.2 million to mitigate diphtheria spread
On Thursday last week, Federal Health Minister Mark Butler said the NT government requested assistance from the Commonwealth in late-April. The current diphtheria outbreak has been described as Australia’s worst since records began in 1991.
“It’s actually all over the five regions of the Northern Territory,”
— Paul Burgess, NT Chief Health Officer
At a press conference on Tuesday, NT Chief Health Officer Paul Burgess said the outbreak had spread throughout the NT, without offering further specifics.
Data transparency
The NT’s approach to releasing location and timing data contrasts with Western Australia and Queensland, where health departments publish information online about when and where cases were identified. SA Health provided case locations and some diagnosis dates upon request, according to the ABC.
In a statement, an NT Health spokesperson confirmed the accuracy of the leaked dataset but said it was not intended for public distribution. The department described the material as a clinical briefing tool for clinicians and service providers and noted details can change as new information emerges about places of acquisition.
NT Health has confirmed one diphtheria death in the NT since the outbreak began. The leaked data indicates aggregate case numbers have decreased over the last three weeks. That trend aligns with public statements made by the NT’s Health Minister and the Chief Health Officer in recent days.
Vaccination campaign
Authorities have moved to bolster immunisation amid the outbreak. A wide-scale vaccine roll-out is underway by the Territory and Federal governments. Last week, the Commonwealth announced a $7.2 million funding package aimed at mitigating the spread of diphtheria.
On Friday, the Australian Centre for Disease Control (CDC) reported more than 260 cases in Australia in 2026, including 159 in the Northern Territory, 102 in Western Australia, six in South Australia and less than five in Queensland. Figures released by State health departments differed slightly from the CDC’s tally, with State health teams reporting 98 cases for Western Australia, seven in South Australia, and three cases in Queensland as of Friday.
More than 10,000 people have been vaccinated against diphtheria over the past few months. On Tuesday, NT Health Minister Steve Edgington said 163 cases had been identified in the NT, of which 115 were cutaneous and 48 were respiratory.
“We have seen a reduction in the number of reported cases and whilst we’re not out of the woods, it is important to recognise that reduction has continued,”
— Steve Edgington, NT Health Minister
Recent decreases in aggregate case numbers, as reflected in the leaked dataset, support those remarks. Officials have continued to emphasise vaccination and clinical vigilance across the Territory’s five regions as public health teams track changes in the outbreak’s trajectory.
