The Doherty Institute says it will be safe for Australia to move out of COVID-19 lockdowns once 70 and 80 per cent vaccination rates are achieved, no matter the number of cases, provided public health measures are retained.
The Institute's modelling has been used by the federal government to inform Australia's pathway out of the pandemic, and as to when to ease lockdown restrictions in line with the nation's vaccination rate.
However, there has been some scepticism, including from state leaders, given the worsening COVID-19 outbreaks in New South Wales, Victoria and the ACT.
Western Australia is refusing to budge from its zero-case goal, and Queensland is warning it may not reopen its NSW border even at the higher jab threshold.
The Institute waded into the quagmire and released a statement on Monday night, saying that opening up at hundreds of cases nationally a day would still be possible at 70 per cent coverage.
"There is light at the end of the tunnel – once we achieve 70 per cent - 80 per cent vaccination we will see less transmission of COVID-19 and fewer people with severe illness, and therefore fewer hospitalisations and deaths," the statement said.
The Institute expects high levels of vaccination to make it easier to live with the virus, but reiterated that it will not be possible to keep cases to zero.
If the country were to re-open at 70 per cent coverage with partial public health measures, Australia would record 385,983 cases and 1,457 over six months, according to the modelling.
However, if current contact tracing, testing and isolating regimes were kept in place and able to operate at an optimal level, the number of infections can be cut to as low as 2,737 cases and 13 deaths over three months.
In comparison, an average year of influenza in Australia leads to around 600 deaths and 200,000 cases.
"We’ve learned from watching countries that have removed all [COVID-19] restrictions that there is no ‘freedom day’," the Institute's statement read.
"We will need to keep some public health measures in place – test, trace, isolate and quarantine – to keep the reproduction number below 1, but as vaccination rates increase, we’ll be able to ease up further and it is unlikely that we will need generalised lockdowns."
Australia has fully vaccinated 30 per cent of its population aged 16 and above, while 52.8 per cent have had one jab.
Earlier on Monday, the Institute's Professor Sharon Lewin moved to allay concerns NSW will still be recording hundreds of daily cases when it reaches vaccination milestones.
"With 70 per cent vaccination, you will get hundreds of thousands of cases, even starting from 30 cases," she told the ABC.
"If you start with 30 cases and you get an increase over time, and you start with hundreds of cases, you are just catching the same curve but you with getting to the peak quicker."
"However, with the presence of vaccination, your deaths and hospitalisations will be greatly reduced with a large number of people protected, and with the addition of public health measures, you will also be curtailing those infections."
The Doherty Institute will provide updated advice to national cabinet on Friday.
'Substantial morbidity and mortality'
Meanwhile, by Australian National University researchers argues at least 90 per cent of all Australians, including children, must be vaccinated before fully relaxing public health measures and opening the international border.
"We found substantial morbidity and mortality is likely to occur if the Australian government sticks to the national plan," Professor Quentin Grafton said.
Prime Minister Scott Morrison said on Tuesday morning "we still have to live sensibly in a COVID-19 world".
"There are not zero restrictions, there are commonsense baseline level restrictions, and I wouldn't even call them restrictions, it's just commonsense behaviour," he told the Seven Network.
The Prime Minister says Australia "has to move forward" and open up when 70 per cent of the population is fully vaccinated.
"That's the advice, that's the basis for the plan. We've all signed up to it, we'll need to get on with it."
Mr Morrison said heavy restrictions, which are affecting more than half of Australia's population across Victoria, NSW and the ACT, could not continue indefinitely.
"Otherwise, we stay in the cave forever. That's not a sustainable solution," he said.
With AAP.
