TGA head John Skerritt has confirmed the government is "hopeful" the first COVID-19 vaccines will be "rolled-out" to Australians at the end of the first quarter next year.
The regulator has designated three vaccine candidates for provisional approval. The three candidates are being developed by Pfizer and its partner BioNTech, AstraZeneca with its partner The University of Oxford, and Janssen.
Mr Skerritt told ABC Radio the companies have provided interim data to the regulator but that they are yet to provide full submissions and that a decision on whether to approve the vaccines is expected in late January or February.
In response to a question about why Australians will wait until March while the US and UK plan to launch their vaccine programs in the next few weeks, Mr Skerritt said it "reflects the differences between the countries."
"They are not approvals that those countries are talking about," he said, adding, "They are emergency use authorisations. They are really reflecting the desperate situations facing those countries. We have to remember that on many days the US is having more deaths on one day than we have had in an entire year related to the pandemic."
He said, "These authorisations require the delivery of the vaccines to be very tightly and closely monitored. In Australia, we want to be able to give an approval to the vaccine so they can be used throughout the country through distribution in partnership with the states and territories."
Mr Skerritt said the regulator "has been impressed" with the COVID-19 vaccine efficacy but there are still questions over durability.
He said the TGA had seen the data on the AstraZeneca vaccine that delivered higher efficacy when administered as a half dose then full dose. Mr Skerritt said it is not unusual but that what will be of particular interest is the level of protection in different population groups.
"So, for example, it may be that the elderly or for young frontline healthcare workers, the protection is higher. Or, it may be a vaccine that is better at reducing transmission and so it is all these things and not just one magic number that is what is important to regulators."
Mr Skerrit said stratification of the data is important. He said, "If there is no data for under 18s, we may not approve the vaccine for under 18s."
He also said the TGA was aware from the outset that AstraZeneca had administered the vaccine as a half and then full dose and that it was delivering a different result to when it was administered as two full doses.
The TGA head said it will not make a difference to the regulator's decision on granting the vaccine provisional approval.
Mr Skerritt added the plan for distributing any approved vaccine is "quite advanced" and that the objective is to vaccinate the country during the calendar year 2021.
The Department of Health recently conducted a limited tender for the distribution of COVID-19 vaccines. The tender documents were not made public.