What comes next in Australia's COVID-19 vaccine rollout?

First in line to receive the jab are frontline health care workers, aged care and disability staff, aged care and disability residents and quarantine and border workers.

It came after the first Australians received the COVID-19 vaccine on Sunday. Among them were Australia's Prime Minister Scott Morrison and chief health officer Professor Paul Kelly.

The federal government hopes every adult who wants to receive a vaccine will be able to do so by October.

The first vaccine to be rolled out in Australia is the Pfizer/BioNTech vaccine.

Australia received 142,000 doses of the Pfizer vaccine last Monday. There will be 80,000 doses made available this week. The remainder will be kept available for second doses, in case there are any supply issues in the coming weeks.

The vaccine was the first to be approved by Australia's Therapeutic Goods Administration. It was approved last month.

The first doses of the Oxford/AstraZeneca vaccine are expected be doled out in early March.

It was provisionally approved by the Therapeutic Goods Administration last week.

Most Australians are likely to receive the AstraZeneca vaccine, as Australia has ordered more doses. As well, the majority of Australia's AstraZeneca vaccines will be manufactured in the country.

Australia will receive 53.8 million doses of the AstraZeneca vaccine (50 million will be manufactured here) and 20 million doses of the Pzifer vaccine.

"Pfizer's first, but it is being made overseas. There is limited supply that we'll be getting of the Pfizer vaccine, whereas for the AstraZeneca vaccine, it's being made by CSL right now in Melbourne, and it's well advanced," Prof Kelly said last month.

"So we'll be getting large supplies of the AstraZeneca vaccine, so that is the one we will have available for most people during this year."

There have been concerns raised about the efficacy rates of the vaccines but health experts have said people should not be worried.

Studies showed the Pfizer vaccine had an efficacy rate of up to 95 per cent after two doses with a 21-day gap, whereas AstraZeneca was found to have an 82 per cent efficacy rate when its two doses were administered 12 days apart.

But TGA boss John Skerritt said this was not relevant.

"Frankly, there's not a difference when you go into the real world whether something is 82 per cent or 90 per cent," he said.

"So I would emphasise that a lot of discussion on the numbers is not particularly relevant. What is important is to get vaccines into people's arms."

At this stage, the provisional vaccination approval for AstraZeneca was for those aged 18 and over.

As well, decisions to vaccinate people over 65 with the AstraZeneca vaccine would be made on a case-by-case basis. While trials of elderly patients over 65 showed a strong immune response in clinical trials, there weren't enough participants to conclusively determine the efficacy for people in this age group.

But Prof Skerritt said the vaccine was recommended for all age groups.

"Our analysis of the data gives us no reason to suspect that the vaccine would not be fully efficacious in older groups," he said.

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On Sunday, Mr Morrison was asked about the AstraZeneca vaccine's arrival date.

"When we have more information on that, we will provide it," he said.

Health Minister Greg Hunt said the approval of the AstraZeneca would double the number of vaccine doses available each week, starting in March.

It came as the first vials of the AstraZeneca vaccine were filled at CSL's Broadmeadows facility last week.

"That will see 1 million doses a week, commencing in late March, made available, and that should see 2 million doses arrive before the end of March, and thereafter continue at one million doses per week," Mr Hunt said.

The federal government has also signed an agreement with Novavax, to distribute its vaccines across Australia.

Australia has ordered 51 million doses of the Novavax vaccine but it had yet to complete its clinical trials.

As well, Australia has joined the COVAX facility - a global agreement to allow countries to buy vaccine doses as they become available.

Under the agreement, Australia has contributed an up front payment of $123.2 million, which would allow the purchase of 25 million vaccines.

Nine vaccines were included in the COVAX facility, including the Moderna vaccine.

Yes, two doses are necessary to ensure there is adequate immunity.

Trials of the vaccines found there was a weak immune reaction after the first dose was given but a strong immune reaction was found after the second dose.

The waiting period between the doses differed by vaccine.

In Australia, the Pfizer vaccine required the second dose at least 21 days after the first. The second dose of the AstraZeneca could be four to 12 weeks after the first.

No. But there was a chance in the future as the University of Oxford was undertaking a study on the use of different combinations of COVID-19 vaccines.