Leading epidemiologists have warned Australia could face a fresh COVID-19 surge next year, similar to that currently being experienced in several European nations.
The warning comes as some jurisdictions moved to further ease their COVID-19 restrictions, while some sates hit major vaccine milestones.
Infectious diseases expert Professor Raina MacIntyre urged for Australia to prioritise booster shots in coming months to help prevent the situation in Europe play out in Australia.
Several countries in the continent have reimposed lockdowns and restrictions in response to a surge in cases during the northern hemisphere winter.
"We need to start thinking ourselves as fully vaccinated if we've had three doses," Professor MacIntyre told the Nine Network on Thursday.
"The immunity from two doses of vaccine, whether it's from AstraZeneca or Pfizer, starts to wane after a few months."
Top-up COVID-19 vaccinations are available for those who had completed their initial course of vaccines six months ago.
The infectious diseases expert said without a large section of the population getting a booster shot, Australia would be vulnerable to fresh surges.
"We shouldn't think that we're exceptional," she said.
"We need to look at the lessons from overseas and we can avoid that."
The latest vaccine figures showed 86 per cent of the national population 16 and over are fully vaccinated, while 91.9 per cent have had their first dose.
Victoria became the third jurisdiction, after the ACT and NSW, to reach 90 per cent fully vaccinated, getting to the milestone on Thursday.
It comes as the NSW government indicated plans to ease back restrictions further when the state hits 95 per cent fully vaccinated or December 15 at the latest.
It includes scrapping all density limits and mask rules being eased, while QR code check-ins will only be required at high-risk venues such as hospitals and aged care.
The measures also coincide for when the lockout of unvaccinated people will end in the state.
NSW recorded zero fatalities for COVID-19 on Thursday but had 276 cases.
Victoria registered another 1254 cases and five virus deaths.
There was just one new case in the Northern Territory after the Top End experienced a recent spike in infections.
In SA, dozens have been forced into quarantine as two COVID cases were detected among interstate travellers, taking the number of infections since the state's border reopened to three.
The ACT registered eight new cases.
Australian Associated Press