Australian kids will finally be vaccinated against COVID-19 next month after approval cleared its final hurdle.
Prime Minister Scott Morrison has also claimed "we're ready to go" if booster shots for adults need to be brought forward, after data suggested a third Pfizer dose will be needed to combat the highly infectious Omicron variant.
In a long-awaited development, the Australian Technical Advisory Group on Immunisation has approved the Pfizer vaccine for use in five- to 11-year-olds.
Children in the age range will begin receiving the jab from January 10, with parents able to make bookings from late this month.
Mr Morrison described the development as "welcome news" for parents, and hoped high uptake for other vaccines would be mirrored in the coming months.
"This will bring great relief to so many mums and dads, who now have a choice on what's best for their kids. They can have peace of mind knowing this has the tick from the best medical regulators in the world," he said.
"Australia is a proud vaccination nation, especially when it comes to protecting our kids."
While children were significantly less likely to suffer severe outcomes from COVID-19,
Health Minister Greg Hunt said vaccinating the group will reduce the likelihood of them spreading the virus to a family member or the broader public.
"Australians can be reassured that by vaccinating their children against COVID-19, they have done everything possible to keep their child safe from this virus," he said.
The approval will bring another 2.3 million children, including nearly 40,000 in the ACT, into the national rollout. Doses administered to the cohort will be one-third the size of those given to people aged 12 and over, with ATAGI recommending they be spaced two months apart.
Around 4.8 million - over 16 per cent - of five- to 11-year-olds have received at least one dose in the US.
The Therapeutic Goods Administration was also mulling an application from Moderna to vaccinate six- to 11-year-olds.
The regulator's approval followed a Canadian review of clinical data for the vaccine, which showed a 90 per cent efficacy against lab-produced COVID-19.
But it came as Pfizer announced initial data suggested two doses were significantly less effective against Omicron, with a third likely needed to ward off the new strain.
Australians are currently eligible for a booster shot six months after becoming fully vaccinated, but ATAGI is considering shortening that time frame as Omicron grows roots in the community.
The United Kingdom is scrambling to deliver boosters as Omicron spreads, halving wait times for residents aged 40 and over.
And with supply constraints which marred the early phases of Australia's rollout over, Mr Morrison said the government was ready to respond to shifting advice.
"They will continue to keep that under close watch ... We would strongly support that, and we are ready to go if that is what they would like to do," he told reporters on Thursday.
Mr Hunt on Wednesday alluded to mounting evidence that Omicron produced milder symptoms than previous variants, but confirmed more data was required.
Australians who have received two doses of the Pfizer jab are currently considered fully vaccinated.
Pressed on whether that threshold would be raised to three, Mr Morrison insisted authorities would simply follow the medical advice.
More than 611,000 boosters have been administered across Australia, and 88.7 per cent of its 16-and-over population is fully vaccinated.
State and territory leaders will receive a briefing on Omicron at a national cabinet meeting on Friday, with Australia's delayed border reopening also set to be discussed.