Another vaccine has joined Australia's COVID-19 booster rollout, with some conditions, after the AstraZeneca jab cleared its final hurdle.
The Therapeutic Goods Administration on Thursday granted the jab provisional approval for use as a third dose for people aged 18 an over, but only after "consultation with a medical professional".
The TGA said the two mRNA vaccines already approved as boosters - Pfizer and Moderna - were the "preferred" options for a third dose.
Announcing its decision, the regulator stressed a booster provided a "strong protection" against severe COVID-19 symptoms, particularly from the highly-infectious Omicron variant.
"The mRNA COVID-19 vaccines Comirnaty (Pfizer) or Spikevax (Moderna) are preferred as the booster dose in Australia, irrespective of the primary COVID-19 vaccine used," its statement read.
"This includes for people who received the AstraZeneca COVID-19 vaccine for their primary course."
Prime Minister Scott Morrison and Health Minister Greg Hunt have both flagged a third dose will soon be required to be considered "fully-vaccinated".
An Australian public assessment report for the decision will be published in the coming days.
AstraZeneca, the only COVID-19 vaccine manufactured in Australia, had been set to make up the bulk of the nation's rollout.
But that plan was dented in June, when ATAGI recommended it be offered to those aged at least 60 because of its links to an extremely rare form of blood clotting.
Prime Minister Scott Morrison shifted his rhetoric the following month as cases climbed amid a sluggish rollout, urging young people to take AstraZeneca if approved by their doctor.
Nearly 94 per cent of Australians aged 16-and-over have received two doses, the current definition of fully-vaccinated.
The federal government has predicted that was likely to change in the coming weeks, as the states pushed for a three-dose requirement.
More than 9.3 million Australians have received a third dose.
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