The Northern Territory government says the modelling it used to help plan its road map to safely reopening is becoming increasingly irrelevant due to the highly infectious Omicron variant.
In November, modelling provided by the Doherty Institute showed that, with 80 per cent of people aged 16 years and older fully vaccinated — and with "low-level" public health measures in place — the Northern Territory's health system would be able to handle 30 to 100 COVID-19 cases per day.
For remote areas, the vaccination benchmark was higher: 80 per cent coverage in people aged five years and over.
Two weeks after reopening borders to interstate travellers, the Northern Territory set a new daily record of 95 COVID-19 cases.
That daily total is expected to rise, prompting concerns the Territory's health system will struggle to cope if cases skyrocket.
Speaking at a press conference on Tuesday, Chief Minister Michael Gunner was unable to provide an estimate of the number of hospital admissions and COVID-19 cases that are expected over the coming months.
He said he had asked national cabinet for updated advice around the modelling now that Omicron was becoming the dominant strain.
Mr Gunner said "essentially, Omicron is twice as infectious, but half as severe".
"If you take the modelling we had around Delta, which has been good and reliable to date, [with] 30 to 100 cases a day that we can have within a hospital system … you're probably looking at a doubling of the volume and still leading to the same hospital outcome."
On Tuesday, Health Minister Natasha Fyles said the modelling upon which the Northern Territory government based its road map to reopening was "not based on Omicron, that was based on Delta".
"[What] we're seeing with Omicron [is] a different virus," she said.
Professor behind modelling says updates needed
University of Melbourne professor James McCaw, who co-led the Doherty Institute's modelling, said the modelling was still relevant, but would need to be "recalibrated" to keep up with the changing nature of the pandemic.
"That work has helped Australia set up its path for a transition from zero COVID to an environment where we are managing severe outcomes," he said.
"But, of course, Omicron, as the new variant with different biology, needs re-evaluation of that work and the national plan."
Professor McCaw said the new variant had changed the relationship between cases and hospital admissions.
"Omicron, very clearly in vaccinated or past exposed populations, is less severe than Delta," he said.
"At a high caseload, there's going to be fewer hospitalisations because of the vaccine or past exposure like we've seen in South Africa."
However, he warned, the Territory faced a risk of higher hospital admission levels due to low vaccination levels in some regions and a higher prevalence of underlying health issues.
John Paterson — chief executive of the Aboriginal Medical Medical Services Alliance NT (AMSANT) — said he was unsurprised COVID-19 cases had surged since borders reopened.
Speaking on ABC Radio Darwin on Tuesday morning, he said "this was just the writing on the wall for us".
"From our perspective, lifting of the borders was too early," he said.
Mr Paterson said he wished the Territory government had delayed reopening to January 17 to allow Aboriginal health services more time to boost vaccination rates in communities "where vaccination rates are at unacceptable levels".
