Coronavirus first arrived in Australia on board China Southern Airlines flight 321 from Guangzhou, which flew into Melbourne on January 19, Four Corners has revealed.
Landing in Australia was a 58-year-old who came from Wuhan, the ABC show said in a
special programme about Covid-19's spread in Australia, which it said was due to a series of "stupid" mistakes by governments and health authorities.
Five days after the plane's arrival, the 58-year-old passenger went to Monash Medical Centre on the advice of a GP.
He was complaining of having a fever, cough and shortness of breath.
Two days later, a 21-year-old woman from Wuhan studying at the University of New South Wales tested positive.
The same week, on the Queensland Gold Coast, a tour group flew in from Wuhan.
A man and woman from the tour group tested positive for coronavirus and were taken to a Gold Coast hospital.
Coronavirus was in Australia, and though it was inevitable that it would come eventually, coronavirus expert Dr Norman Swan told the programme that mistakes, fiascos and mishandling since has seen it spread.
Swan and other doctors told Four Corners that these mistakes could mean that in as little as 12 days, Australia will be "like Italy".
Mass sports events, the Ruby Princess fiasco, not closing borders early and "messy" messaging from the PM are among the deadly mistakes that will cost Australians lives, Four Corners reported.
Australians have also not taken isolation or quarantine seriously, and as a result up to 50 per cent of the nation could become infected in a "worst-case scenario", the show warned.
One estimate is that Australia is currently 12 to 20 days behind the coronavirus catastrophe that is the reality in Italy.
And it could be "like World War I ... if the numbers run away from us".
Swan told the programme: "We had football games, basketball games going, with tens of thousands of people turning up. Two reasons why that was mad, completely mad and stupid ...
"The first is even though there's not much Covid-19 in the community, you're increasing your risk of getting it the larger the number of people you come in contact with.
"The second reason is contact tracing," he said.
"You can't do it when you catch it at a football match and you can't do it when you're at a gathering of 500 people outside."
Swan said inevitably our first case would have come out of China, but "we should have known that it was going to take off quickly around the world and the demand for testing kits and other things was going to be huge".
John Daley, CEO of the Grattan Institute, said Australia had been "so far … very slow to close our borders".
"So although we were relatively quick off the mark in terms of constraining travel from Wuhan, where the epidemic originated, we were pretty slow to close our borders to traffic from anywhere else ... many other countries in the world had a significant number of cases of the virus.
"And therefore – and indeed this is exactly what turned out – had a significant number of cases of the virus.
"And a lot of people who got off planes in Australia and allegedly went into self-isolation, in practice wound up infecting plenty of other people in Australia.
"And now we have a significant number of cases in the community.
"Which means that we have got no chance of tracking and tracing them all.
"So we should have closed the borders much earlier than we did."
Professor Raina Macintyre, professor of emerging infectious diseases at the Kirby Institute, said: "In a worst-case scenario, maybe 50 per cent of our population might get infected.
"So you work out the numbers, then, in terms of how many people are going to die and then how many people are going to need hospital.
"We know that about 20 per cent of everyone who gets infected gets seriously ill and needs a hospital bed and some of them need an intensive care bed.
"According to the modelling we've done for other serious infections, you will rapidly run out of the capacity to treat people and to provide high levels of intensive care."
Swan said "what went wrong in Italy is that they were asleep at the wheel, when they knew that they should have been at risk and be alert to the process".
"And they started getting cases and they thought it was the flu. And by the time they responded and it was too late."
But he said we are currently "12 to 20 days behind Italy".
"The numbers are going up almost vertically in New South Wales, Victoria is not far behind.
"So once it starts doubling at significant numbers, it just runs away from you.
"So if you're going straight up and you're doubling every three or four or five days, it's year seven maths.
"We're going to be where Italy was. Change that curve. If something doesn't change that curve, that's where we're going to be. Simple as that."
Dr Andrew Miller, President of the Australian Medical Association in Western Australia, said Australia had suffered "mixed messaging" from politicians in the beginning of the pandemic.
"Part of the mixed messaging was the problem that the way that our media and politics works is that everyone comments on everything, pretty much."
"And they have a lot of media advisers who suit the particular person who's delivering the message. That's not the way to deal with a health crisis."
Professor Macintyre said healthcare workers would be forced to work without adequate personal protection equipment (PPE) and they're going to be infected.
"They're going to die, like they are in Italy and like they're getting infected in the United States," she said.
"It would take a generation to replace healthcare workers.
"They're not like, you know, drugs and vaccines that we can just crank up the production and get some more.
"We can't afford to take a soft approach because we have to ensure that our healthcare workers are not in that situation, as they are in Italy or Spain.
"In Spain, doctors are weeping, because they have to take the ventilator out of patients to give it to other people who are younger, you know, because those patients are too old. And they're getting infected."
Swan said it was reasonable to compare the situation with wartime.
"If you're a general commanding a brigade or whatever, and how many casualties you're prepared to accept, already in Britain, it looks like the Somme," he said.
"And I'm not overstating it.
"The stories you're getting out of hospitals in Britain where consultant physicians, consultant surgeons are on heart-lung bypass because of coronavirus, where they're running out of PPE.
"And they're wearing loose masks and aprons instead of PPE, and they're being sent into battle by their bosses,
"It's just like World War I.
"As the number of infections and deaths continues to rise, there is now growing concern about how those on the front lines can cope."
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Professor Sharon Lewin said she still believed it was possible "to flatten the curve" because the other situation was "we end up like Italy and I don't want to see that".