Australia’s international border closures are likely to be one of the “last things” to be dumped even after the vaccine is rolled out.

The nation’s chief medical officer Professor Paul Kelly has again warned that the “new normal” that emerges after the first phase of the vaccination program is unlikely to involve trips to Bali, Fiji or Europe for most Australians.

And he’s revealed teenagers and children – effectively anyone under the age of 18 – will be denied the vaccine during the first year of the program.

Once its safety is proven, health chiefs may consider giving the vaccine to older teenagers in the 16 to 18 age bracket.

“On travel, we have to be very careful and we have said this on many occasions, I have said it. The first vaccinations, as they roll out in a few weeks in Australia, will not change everything back to normal,” Professor Kelly said.

“We are in such an envious position at the moment compared with the rest of the world.

“Unfortunately, international border changes will be one of the last things to change rather than the first.”

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Even as the rollout of the vaccine starts, he warned there were no immediate plans to allow travellers to quarantine at home or for shorter periods.

Prime Minister Scott Morrison and deputy PM Michael McCormack stressed today that final decisions will be driven by medical advice.

On Monday, Health Department chief Professor Brendan Murphy said international travel was unlikely to resume this year.

Asked if he agreed with this assessment, the Prime Minister said Tuesday the decision would be guided by the health advice.

“Now, at the moment, that is the Secretary of Health’s assessment, but we’ll see how things play out over the course of the year,” the PM said.

“All of it has been based on the information and advice that has come through and the same will be true when we make decisions over the course of this year, particularly when we get to the other side of vaccines having been introduced in Australia about what will happen with international borders.”

But he played down suggestions this would trigger a massive bailout for the domestic tourism industry, stressing that the majority of the spending was Australians holidaying at home.

“The domestic tourism industry accounts for about 70 to 80 per cent of the overall tourism industry in Australia, thereabouts,” he said.

“But the bread and butter of the tourism industry in Australia has always been the domestic tourism sector. And in this unusual time, Australians who are big overseas travellers are increasingly in a position and will want to more and more see their own country. So that’s going to have its obvious impact.”

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Deputy Prime Minister Michael McCormack said the medical advice was paramount.

“On international travel, of course, we want to see our international flights resume as soon as possible,” he said.

“But we also want to make sure that we continue to have the health outcomes here in Australia that we’ve had, we’ve been the envy of the world when it comes to health outcomes. I spoke to (Qantas CEO) Alan Joyce yesterday. He’s obviously concerned and they opened up the bookings from July. And of course, they’re keen to see international flights resume as soon as possible.”

Earlier, Prof Kelly also stressed that the “efficacy” of the vaccine – whether it protected 90 per cent or 70 per cent of people from contracting COVID-19 – was not the only measure of success.

“There was debate last week about whether the AstraZeneca vaccine was somehow less effective than the Pfizer vaccine, that is related to the phase three clinical trials, we talked about that last week,” he said.

“The efficacy of the vaccine is only one component, there are three components to effectiveness of vaccination programs, one of them is the efficacy of the vaccine, the other is the duration of the effect of the vaccine.”

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In short, Prof Kelly said the vaccines were so new that experts didn’t know how long they would provide protection for and how soon a booster shot might be required.

“We do not know how long these vaccines are for because they are so new. So whether we need to do a booster at some point remains to be seen,” he said.

Prof Kelly also suggested there was wisdom in giving many people the vaccine – even if some were less effective than others.

“Efficacy, the duration of effect, and the third what is the coverage, we need to give as many vaccines out into the community as possible, if we do not do that than the effectiveness will be indeed affected,” he said.