About 40 per cent of future COVID-19 cases in the ACT will go unconfirmed by tests for the virus, health authorities said, before the territory embarks on the most relaxed isolation requirements since the pandemic began.
ACT Health also has no plans to run a sero-survey to determine how prevalent COVID-19 antibodies are in the territory's population, and said it had not modelled the attack rate of the virus, which is the percentage of the population that had been exposed.
Short-term modelling on case numbers predicated stable cases over the coming weeks that were generally inline with current daily case counts, a spokesman for ACT Health said.
"ACT Health does not model the historic number of unreported cases, which international and interstate experience shows are generally mild or asymptomatic cases," the spokesman said.
"Instead, ACT Health has used modelling to predict future short-term projections of daily cases numbers, hospital and ICU admissions."
Work is under way in the ACT to understand COVID-19 infection rates, which "change over time based on vaccination levels and timings, as well as behaviour of specific variants".
The spokesman said there was not enough data to support a reliable estimate of the total number of unreported COVID-19 cases in the ACT since the start of the pandemic.
"ACT future models have assumed under-reporting of around 40 per cent. Applying this figure historically is difficult noting that the proportion of under-reporting is likely to be highly variable over time due to behaviour of different variants and differences in test seeking and self-reporting behaviours," the spokesman said.
More than half of Canberrans have possibly had COVID-19, even though officially diagnosed cases account for about 20 per cent of the population, experts told The Canberra Times this week.
Associate Professor James Trauer, an epidemiological modelling expert at Monash University, said official COVID-19 case numbers were probably between two and five times smaller than the number of actual infections.
The real numbers associated with the COVID-19 outbreak in Canberra could be more than 200,000 cases in a city of 431,000 residents. There have been 98,760 cases of COVID-19 since the pandemic began.
Health authorities reported the death of a woman in her 80s with COVID-19 on Saturday, along with 975 new coronavirus infections. The woman was the 50th person to die with COVID-19 in the ACT.
COVID-19 hospitalisations in the ACT have slightly decreased, with 55 virus patients in Canberra hospitals. There are two in intensive care but none were ventilated.
Quarantine rules for close contacts of confirmed COVID-19 cases will be eased from 11.59pm on Tuesday, after the government this week confirmed it would follow the lead of Victoria and NSW.
However, students who are close contacts of COVID-19 cases will not be able to attend ACT public schools even if they are asymptomatic and test negative to the virus for at least the first two weeks of second term.
Education Directorate director-general Katy Haire said on Friday public schools would retain the safety measures that were in place in term 1 while officials consulted on the changes.
