The COVID-19 pandemic rapidly forced changes in Australia on Thursday, starting with Qantas announcing it was suspending international flights from late March.
The carrier is busy on the phones to customers, telling them what it means for their bookings. We've asked Qantas what happens next.
Overseas, China's Hubei province reported no new cases of coronavirus for the first time since the outbreak. Has its lockdown worked? What else is stopping the virus overseas?
We asked experts which international responses to the health crisis they believed had been successful so far.
Qantas and Virgin are suspending international flights. I had one booked, so what happens now?
Qantas will suspend international flights between late March and at least the end of May 2020. For people who booked an international flight in that period, that flight will be cancelled. They can receive a credit, which they can use to book flights in the future. Change fees usually associated with rebooking a flight will be waived.
According to the Qantas website: "Customers may also be able to cancel their booking and request a refund, however they may be charged a cancellation fee, as per our fare rules."
Qantas has said there are long wait times at its customer contact centres as people try to change their travel plans as a result of coronavirus. The company has asked customers only to call if they have travel within the next 48 hours, so it can manage demand.
If customers booked their flights through a travel agency or third-party website, they will need to contact them directly to change their booking.
Virgin Australia announced on Wednesday it will suspend international flying from March 30 until June 14.
Customers with new or existing domestic and international bookings through to June 30, 2020 can change their flight to a later date, and/or a different destination, without incurring a change fee.
People who no longer wish to travel can cancel their flight and retain the value of the booking as a travel credit.
Virgin Australia will contact customers who have booked an international flight for between March 30 and June 14 within the next 14 days via email. Travel agents will make direct contact with people who have booked Virgin flights through them.
Similarly to Qantas, the company has asked customers not to get in contact unless they are travelling in the next 24 hours or need immediate assistance to return home or to their point of origin.
Which countries have responded the most effectively to the COVID-19 pandemic? What have they done right?
We've heard of authoritarian lockdowns in parts of China, large volumes of testing in South Korea and school shutdowns to come in Britain.
But experts have said countries need to tailor their response to COVID-19 according to their own circumstances.
That makes it hard to pick out a "model response" for everyone to follow. Medical and public health experts point out strengths and weaknesses throughout the different international responses.
China was initially slow to deal with COVID-19 but later acted vigorously with authoritarian measures, locking down Hubei province.
South Korea has extensively used contact tracing and self-isolation, which have proved effective in reducing the spread of COVID-19.
While the UK government initially followed a policy of allowing the epidemic to proceed unrestrained, it has quickly reversed course.
Monash University medicine professor Paul Komesaroff said the US government's initial denial of a problem led to a critical loss of opportunity, from which health officials were desperately trying to recover.
"The irresponsible statements and policies by the President undoubtedly has cost lives," he said.
"However, even there, the response now is more realistic, both in terms of the health response and the economic measures that are being initiated."
University of Sydney global health researcher Associate Professor Adam Kamradt-Scott suspects in the coming weeks to see a worsening situation in the US.
He said it had "acted slowly to stem the spread of COVID-19 in large part because President Trump refused to acknowledge the spread of the virus was a genuine threat".
Taiwan's response has been held up as a model by some. It banned the export of face masks, and acted quickly to protect people from the virus.
La Trobe University epidemiologist Hassan Vally said Taiwan had not left much to chance.
"They were ready for this, they knew to take it seriously, they went hard and they went early. They had multiple public health measures activated quickly," he said.
Associate Professor Kamradt-Scott said there was no one answer in responding to COVID-19, mainly because each country's outbreak unfolded differently based on a large number of factors.
"That necessitates each country to respond to their national outbreak, and not be bound to one single playbook," he said.
"There is not one measure that will work, but rather a combination of measures. We need a variety of measures, implemented at different times, in order to respond."
Experts agree that timing is critical in responding to the virus.
Associate Professor Kamradt-Scott said it was a matter of acting early to implement public health measures that were proportionate to the spread of the virus in that jurisdiction.
"Acting too early can have unintended economic consequences, whereas responding too late can clearly have serious implications for human health," he said.
"The challenge for governments is getting the timing right with the right measures."
Professor Komesaroff cautioned against over-generalising from experiences overseas.
"Just because one country imposed strict, authoritarian measures that led to a reduction in new cases does not mean that this is the most appropriate approach for us here," he said.
"What is possible and appropriate depends on the local culture and the actual circumstances of the disease."
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- For information on COVID-19, please go to the federal Health Department's website.
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- If you have serious symptoms, such as difficulty breathing, call Triple Zero (000)