The rollout of vaccines for COVID-19 across the world are not guaranteed to open the door to international travel, Australia's chief medical officer has said, as a legal challenge is mounted to the closed international border.
Across the United States and United Kingdom, vaccination is starting for the elderly, vulnerable and health workers, but a key aspect of the vaccine means Australian health authorities are not yet confident to allow people who are vaccinated to travel.
Early data from some of the leading vaccines show they can stop a person from getting sick from coronavirus, but don't stop them from being able to pass the disease on to others.
According to Acting Chief Medical Officer Paul Kelly, it is this risk that is holding up giving vaccinated people the green light to travel.
"That's ... a decision that will be guided by the best medical advice," Professor Kelly said, explaining the government's advisory group on immunisation was looking specifically at how the vaccine would affect travel.
"It sounds simple, but it's not simple. I think it will rely very much on where people have come from, what vaccine they've had, whether they've had the two doses, when they had those two doses, what is the situation here in Australia," he said.
"At the moment, unfortunately, the vaccines that we know most about don't appear to demonstrate any protection from transmission of the virus. They are very effective at stopping disease from the virus in an individual person, but it may well be that that transmission might continue."
Professor Kelly said the government's advisors were developing modelling to analyse how a vaccine would affect international travel.
"Vaccination is clearly a very new and emerging component of our risk mitigation for overseas travel. So it's too early for me to say one way or the other how that's going to affect it. We're certainly looking at how that might affect both incoming travel and people going overseas," he said.
Almost 40,000 Australians are still stranded overseas and registered with the Department of Foreign Affairs and Trade. They had long held out hope that a vaccine would mean limits on incoming travellers and quarantine restrictions would be lifted, but that now seems unlikely.
"We are not lifting international borders at present and we have no immediate plans to do that," Prime Minister Scott Morrison said on Wednesday morning.
While free travel between Australia and New Zealand is set to be available early next year, those with loved ones in other countries are set to have much longer to wait.
"We're taking this very cautiously. The reason we've done so well is we've been so careful around our borders," Mr Morrison said.
"I hope that we can see international travel resume well into next year but I'm not expecting it, really, certainly not in the first quarter of next year.
"In the quarter after that, a lot would have to change to see that happening at any sort of industrial scale."
Almost 10,000 people are looking to come to Australia from India and another 4500 from the UK.
Conservative think tank LibertyWorks has announced it will challenge the government's ban on Australians leaving the country in the Federal Court, where they are set to argue the government did not have the power to make such a decision under the Biosecurity Act.
LibertyWorks President Andrew Cooper said Health Minister Greg Hunt had overstepped in putting the ban on Australians travelling overseas.
"It's an illiberal and a draconian restriction on the free movement of Australian citizens many of whom want to see family and loved ones or to attend to urgent business in other countries," he said.
"Preventing people from travelling overseas does nothing to make Australia safer. But it does create unnecessary pain for families who want to be together for Christmas or during this difficult and worrying period of global pandemic."
- With AAP