On Friday, Australia recorded no new cases of COVID-19 being caught by anyone from someone else in the community - and experts say that's raised the hope of state borders being reopened in time for Christmas.
But not quite yet.
Professor Adrian Esterman of the University of South Australia told The Canberra Times that we would need a bit longer before barriers on borders could be removed, ideally four weeks with no cases or with only a handful of cases.
The period of incubation of COVID-19 (the time it takes for symptoms to develop after catching it) can be as long as 14 days.
"For disease elimination, there must be zero new cases of the disease in a defined geographic area," he said.
There are a tiny number of cases (1 per cent of the total) which take longer than 14 days to emerge after infection, so to be really safe, two periods of 14 days would be needed before Australia could be said to have eliminated the disease - in other words, a month: just in time for Christmas.
"A sensible approach might be to define the elimination of COVID-19 as a 28-day period of no new cases in any state or territory - double the incubation period," Professor Esterman said.
"Any state or territory that achieves disease elimination could then reopen its borders with any other state or territory that has also achieved this."
But despite the headlines on Friday about zero cases, there was one new case in NSW which crept into the figures late, so does that end hopes of a Christmas opening?
Professor Esterman, who is one of the country's experts on the way diseases spread, thinks it wouldn't scupper the idea of reopening borders.
He thinks small numbers of cases would present a risk but a manageable risk which would be worth governments of states and territories considering.
"It would be a matter of risk. Is each government prepared to take that risk?" he asked.
Assuming that the numbers of new cases remain at or near zero, the risk of open borders would be much lower than in earlier days of the epidemic because the ability to trace the contacts of new cases is so much better than it was.
Many experts blame flawed systems and human failings for the Victorian outbreak which took so long to control.
Security people in the quarantine centres on Melbourne were lax and their laxness allowed the infection to get out.
Professor Esterman thinks that this was a "one off" and great improvements have been made so any new outbreak could be brought under control much more quickly.
To sum up the expert view: there is a chance of free movement within Australia by Christmas. We're not there yet but we are definitely going in the right direction.
And there is an even greater chance of movement between states and territories which are COVID-free by Christmas, even if the whole country hasn't opened up.
And if Australia is COVID-free and New Zealand is COVID-free, there must be an increased chance of quarantine-free movement across the Tasman Sea.
International travel beyond New Zealand would take a lot longer given the explosion of infections in Europe and the United States.
But there is some hope there, too.
There are indications that at least two of the potential vaccines are effective and may be approved for use by Christmas.
Australia's Health Minister Greg Hunt has said that when a vaccine was available, the elderly and health workers would be first in line.
Addressing the media, he said that over time everybody who wanted vaccination would be able to receive it.
"What we want to do is to give every Australian who seeks to be vaccinated, that capacity over the course of the coming twelve months," Mr Hunt said.
Your chances of visiting your children or grandparents in Australia for Christmas are rising.
Your chances of seeing them abroad by the following Christmas are rising, too.