One of Australia's top doctors says the country may actually want the new Omicron variant of Covid-19 to spread - as he warned the nation not to panic.
Dr Nick Coatsworth said early reports from southern Africa suggested that while new variant spread faster, its symptoms were far milder in vaccinated patients.
'If this is milder than Delta you actually want it to spread within your community,' the former deputy chief medical officer told Nine's Today show on Monday.
'You want it to out compete Delta and become the predominant circulating virus. So, that shows you how much more we have learn about this
'It could be that we want Omicron to spread around the world as quickly as possible.'
One of Australia's top doctors says the country may actually want the new Omicron variant of Covid-19 to spread - as he warned the nation not to panic. Dr Nick Coatsworth said early reports from southern Africa suggested that while new variant spread faster, its symptoms were far milder in vaccinated patients. 'If this is milder than Delta you actually want it to spread within your community,' the former deputy chief medical officer told Nine's Today show on Monday. 'You want it to out compete Delta and become the predominant circulating virus. So, that shows you how much more we have learn about this 'It could be that we want Omicron to spread around the world as quickly as possible.'
Genomic testing has confirmed two overseas travellers who arrived in Sydney from southern Africa have been infected.
Both passengers arrived on Saturday night and are in isolation in the Special Health Accommodation. Both are fully vaccinated.
The two passengers were among 14 people from southern Africa who arrived on Qatar Airways QR908, Doha to Sydney, with the remaining 12 undertaking 14 days of hotel quarantine.
Australia has now shut its borders to nine southern African countries and states have brought in new rules for international arrivals amid concern over Omicron.
Dr Coatsworth - who was the initial face of the country's vaccine rollout - hailed the swift action.
'The Australian government's taken some judicious but measured responses in terms of closure of international flights from southern Africa,' he said.
'There's a lot we need to find out and I don't think there's any strong evidence at the moment - apart from the fact that it's got 30 mutations - that those mutations are going to have the sort of negative effect.'
He said the information available so far had left him 'probably a little less worried'.
He added: 'I definitely don't think we should be waking up to any sort of panic. This thing is only 72- hours old. There's too few cases at the moment.
'There's three elements to a variant of concern. It can transmit more quickly, it can be more deadly or it can evade the vaccine.
'It's the first one. The speed at which it's spreading in South Africa is what makes it a variant of concern.
'The South African ministry of health said most cases have been mild.'
Dr Coatsworth said at this stage there was no need to rush forward the vaccine booster program until more was known about the new strain.
'Definitely not at this point,' he said. 'We don't know enough. Premature calls for action like that when we know so little are a little bit counter-productive.
'Based on the information we have at the moment, we shouldn't really change our plans.
'The only thing we should change is mild restrictions on the number of people coming into the country from certain other countries but at the moment everything else can go on as planned.
'We will learn a lot more from the laboratories, from the World Health Organization, over the coming days.'
Dr Coatsworth spoke out as fears Christmas holiday plans could be thrown into chaos as international and state border closures begin to domino and panic spreads about the emergence of the 'super-mutant' Covid variant Omicron.
South Australia and Western Australia tightened border restrictions as other premiers around the nation also start to consider harsher controls.
Scientists are in a race against time to answer three vital questions about the variant that doctors said caused 'unusual' symptoms, as Scott Morrison and Australia's business leaders call for calm.
The Australian Health Protection Principal Committee, which gave the prime minister an emergency briefing on Sunday night, are scrambling to determine how transmissible Omicron is, whether it is more severe than other strains, and if it is vaccine resistant.
Trade and Tourism Minister Dan Tehan said he couldn't rule out extending restrictions to other nations if the outbreak spreads, or more drastic measures if Omicron turned out to be dangerous.
'We've taken a cautionary approach, that's what we'll continue to take as we work through what this variant is all about and what potential impacts it may have,' he said.
'We think that's got the balance right at the moment, but there's obviously more work that needs to be done in understanding the new variant and the potential impacts it might have.'
Mr Morrison said after his meeting: 'We need to be very responsive to the further evidence that is becoming available and the expert medical advice.
'The goal is to ensure that our public hospitals and health systems are able to cope with this virus so we can live with the virus.'
NSW, Victoria, and the ACT temporarily re-imposed a 72-hour self-isolation requirement for all international arrivals.
Two other passengers who tested positive to Covid after arriving from southern Africa, one in Sydney and another at the Howard Springs facility near Darwin, are being screened to see if they also have the Omicron variant.
Victorian health authorities are also investigating whether the potential third NSW Omicron case could have infected anyone there while on a trip to Victoria.
Government sources said the Victorian Government was considering extending quarantine and reintroducing mask mandates in some settings.
New health orders could be announced as early as Monday, the sources said, and were likely to be also rolled out by state and territory leaders across the country.
NSW Jobs Minister Stuart Ayres announced on Sunday the state government was prepared to clamp down on travellers arriving from overseas.
'We will take the necessary measures, including restarting quarantine if required, to protect our community and our economy,' he said.
A government source said work was underway to restore hotel quarantine if required, but the preferred option will be home isolation unless the strain was deemed extremely severe.
WA Premier Mark McGowan on Saturday evening shut his state's borders to South Australia in a draconian effort to lock out the mutant new strain, as it allows in visitors from NSW and Victoria.
The ruling means only vaccinated South Australians can enter WA, where they must immediately go into quarantine for 14 days.
South Australia also tightened its border rules following the emergence of the Omicron variant.
All international travellers and people arriving in SA from high-risk locations in Australia will once again be required to quarantine for 14 days.
First discovered in South Africa, Namibia, Zimbabwe, Botswana, Lesotho, Eswatini, the Seychelles, Malawi and Mozambique, the variant has since spread to several other nations across the globe.
The doctor who first raised the alarm on Omicron said patients are presenting with 'unusual' symptoms.
Dr Angelique Coetzee, who runs a private practice in the South African capital of Pretoria, said she first noticed earlier this month that Covid patients were presenting with odd symptoms.
The doctor, who has practiced for over 30 years and chairs the South African Medical Association, said none of the Omicron patients suffered a loss of taste of smell typically associated with Covid.
Instead they presented with unusual markers like intense fatigue and a rapid pulse.
'Their symptoms were so different and so mild from those I had treated before,' Dr Coetzee told The Telegraph.
She was compelled to inform South Africa's vaccine advisory board on November 18 when she treated a family of four, all of whom were suffering with intense fatigue after testing positive for Covid-19.
Australian virus expert Professor Tony Blakely it will take weeks before more is known about the strain and if it's resistant to vaccines.
'It's quite likely that this will precipitate new branches of vaccine development, there's just so many mutations on this virus it would seem most likely we will need new vaccines,' he told the Herald Sun.
That bleak possibility could send much of the globe back into lockdown but he said there could be one upside.
If Omicron is more infectious but less deadly and results in less hospitalisations, it could displace Delta as the most common form of Covid but lower the global death toll.
On the other hand: 'the worst-case scenario is it's more infectious, it's more virulent, and it's resistant to current vaccines,' Professor Blakely said.
The manufacturers of the Pfizer vaccine, BioNTech, said even if the new variant is resistant to vaccines it could create and ship a modified jab within 100 days.
Australian Industry Group chief executive Innes Willox worried an overreaction to the new variant could be almost as bad as the virus for businesses that were already struggling in the wake of Delta lockdowns.
'While some caution is understandable, the response to any new and inevitable variant needs to be targeted, proportionate and take into account the nearly 90 per cent of us are vaccinated and tired of lockdowns and border closures,' she told The Australian.
'We are just getting our economy back on its feet, but investment and confidence are still uncertain. An over-reaction both in terms of timing and proportionality around shutting Australia off from the world, and state from state, would be devastating.'
Australian Chamber of Commerce and Industry chief executive Andrew McKellar also warned that 'with international and domestic border closures finally reopening, business cannot afford to take a backwards step'.
'State and federal leaders must stick to the national plan to get Australia back open, and to stay open,' he said.
'Continuing to drive up the vaccination rate and encouraging everyone to get a booster shot is the best way to protect the population, rather than imposing further restrictions.'
Flight Centre founder Graham Turner is resigned to the fact the travel sector will see a huge decline in bookings over coming days and weeks.
'If the vaccines are effective against the new strain, it won't change anything in the medium term,' he said.
'It just depends on how panicked governments get, it's a political thing, they have to show they're doing something.'
University of NSW epidemiology professor Mary-Louise McLaws said 72-hour self-isolation in NSW and Victoria was not enough and advocated a return to 'Fortress Australia' immediately.
'Omicron still not fully understood. Is transmission faster, does it reduce vaccine efficacy, is it as hard to mitigate outbreaks [like] Delta?' she tweeted on Sunday.
'Until +90% vaccination coverage of total pop (not just +12yr) quarantine must be supervised for every traveller from every country. [With] testing on day-1, 4, 5.'
Dr Paul Griffin, director of infectious diseases at Mater Health in Brisbane, was far less concerned and said it was still too early to judge the risks of Omicron.
'I don't think we're back to square one. A lot of us thought this is what this virus is going to keep doing, going to keep evolving and we are going to keep finding new variants,' he told ABC.
Similar sentiments were echoed by Victorian chief health officer Brett Sutton, who conceded that it was 'impossible' to keep the strain off Australian shores but measures were already in place to reduce its spread.
Professor Sutton said he was 'very confident' vaccines would provide some level of 'cross protection' for the new variant, even if Omicron differs significantly in terms of 'how our immune system recognises it'.
'This is not back to the beginning,' he said.
'We are not back at square one by any means. The vaccination coverage that we've got - over 90 per cent of eligible Victorians being fully vaccinated already - is absolutely more than useful.
'It is absolutely critical in protecting them and will, I'm sure, provide protection against these variants as well. We just need to understand how much.'
Professor Sutton said 'not really enough' is known about Omicron but it seemed likely it would become the new dominant variant of Covid.
'It certainly seems to have spread very quickly in southern Africa, and in the republic of South Africa in particular across many, many provinces and numbers have increased very significantly over a short period of time,' he said.
'We just need the time to be clear about whether this virus is in this country already, and the extent to which it has spread globally.
'It's going to be impossible to keep out, I imagine. If it's more transmissible than Delta, then it will become the global variant for sure.'
Despite Professor Sutton's assurance, fatigued Victorians who are fresh out of Covid lockdown are already bracing for reinstated restrictions that may be cast over the state to tackle the new variant.
Rhonda Andrews, chief executive of the corporate and private psychology service the Barrington Centre, said the company's 320 psychologists were being bombarded with calls as anxiety heightens over the unfolding situation despite general optimism around reopening.
'We're going to get people who are going to feel like that optimism has just been shattered and they feel like, 'Here we go again',' she told The Age.
Ms Andrews said the latest health threat was likely to cause a state called 'cumulative distress'.
'What happens when people get into that mood or mindset is that they go back to what they've experienced since March 2020. It's not just as if they are dealing with the new variant, they actually relive what they've lived in the past 20 months,' she said.
The two infected passengers were on Qatar Airways QR908, via Doha, which touched down around 7pm. Twelve other passengers on the same flight who travelled from southern Africa are undertaking 14 days of hotel quarantine.
As well as the two arrivals in Sydney, another two African arrivals have also tested positive for Covid in different states and the same testing will be done on their samples to identify the strains.
The first arrived in NSW on November 23 before travelling to Victoria two days later, sparking fears Omicron is already in the southern state.
Victorian health officials will complete a full interview with this case tonight to track down any close contacts in the event the passenger does have the Omicron variant.
The second, a man, arrived on a repatriation flight from South Africa to the Northern Territory on Thursday and was in isolation at the Howard Springs quarantine facility.
Meanwhile, Queensland authorities said they were unable to guarantee the state's border would reopen once 80 per cent of the state's population was vaccinated as planned, in light of the emerging health threat.
Acting chief health officer Peter Aitken said officials were monitoring the situation and incoming visitors from hotspots interstate may be subjected to quarantine.
'We'll make that decision when there's evidence available that needs a change in position. But at this stage there's no evidence available to support a change in position,' he said.
There are 10 people from the nine southern African countries of concern quarantining in Queensland.
If it is more transmissible than Delta, as feared, experts said Omicron could become the second-most contagious disease after measles.
'What we always feared is a mutant that comes up that can spread faster than delta and can have the features of beta which is more immune evasive,' Sydney University virologist Tony Cunningham told AFR.
Omicron, deemed a 'variant of concern' by the World Health Organisation, has more than 30 mutations in the spike protein alone, and Professor Cunningham said the changes were surprising.
'It really gives the lie to the early thoughts that we had that this is not a particularly mutating virus. If it's more spreadable than Delta, it's approaching the second-most spreadable virus that we have, which is chicken pox. Number one is measles. Delta was number three,' he said.
'But if Omicron beats delta then this is a real issue for the world.'
Professor Cunningham said he believed the vaccines would still remain partially effective against Omicron but the duration of immunity could be shortened, with studies underway to determine how the strain interacts with those antibodies.
The prime minister urged people to get vaccinated as it was by far the best way for Australia to defend against any form of Covid.
'I want to encourage it and if you've already had your vaccine, your second dose and it is six months, please go and get your booster shots,' he said.
'Booster shots are very important to ensure Australia is in as strong a position as we can to deal with these sorts of issues. This is not like it was back in February and March and 2020.'
Mr Morrison said the government had good advice on Covid.
'The uncertainties are not like they used to be. We have good systems which have been proven which is demonstrated by one of the lowest fatality rates, strongest economies and highest vaccination rate in the world,' he said.
He said the Australian people and the government has worked 'to open safely and remain safely open'.
NSW recorded 185 new Covid-19 on Sunday morning, while Victoria recorded 1,061 new cases and four deaths.
Health Minister Greg Hunt said the government would not hesitate if more needed to be done to combat the Omicron strain.
'Overnight international evidence came in and we took the immediate steps yesterday and will continue to do that to protect Australians,' he said.
'Yesterday, there were over 3,800 passengers who arrived in Australia... 54 were from southern Africa.
'They had been there and identified in the previous 14 days across the nine countries and what we are pleased to see is that all of the orders that were issued yesterday had been put in place, actions had been taken, Border Force is implementing in states and territories and public health is supporting.'
Northern Territory authorities as yet have no genomic sequencing in relation to the passenger's infection strain, NT Health Minister Natasha Fyles said.
But the person has been in supervised quarantine at the national Howard Springs facility, south of Darwin, since arriving, she said.
'So there is a very low risk to the community and we wish that person well,' Ms Fyles said.
NT health chief Dr Charles Pain says he expects the sequencing test results for the South African case to be processed by Monday.
The passenger arrived in Darwin on Thursday and his positive virus result was confirmed on Friday evening.
The new quarantine restrictions came into effect at midnight on Saturday and require all international arrivals in the three states - including fully vaccinated passengers - to be tested when they land.
The nine African nations from which entries to Australia have been banned are: South Africa, Lesotho, Botswana, Zimbabwe, Mozambique, Namibia, Eswatini (formerly Swaziland), Seychelles and Malawi.
Dr Griffin, from the Mater Health in Brisbane, said 'The way we've controlled this virus so well so far will still work, will still help us.
'Things like masks, social distancing, ventilation will protect us from Omicron.
'The main thing is we still don't really know the properties of this variant, so it certainly has a large number of concerning mutations but now we have to establish what that means in terms of how infectious it is...
'Its capability to evade our vaccines, and all of that hasn't been established yet, so he we just need to get that information now,' he said.
The introduction of self-isolation rules in the three states comes only four weeks after Victoria and NSW removed hotel quarantine requirements for fully-vaccinated travellers on November 1.
The ACT ended hotel quarantine for overseas arrivals on November 12.
The Victorian health department says the new rules will apply to unvaccinated children under 12 and unaccompanied minors, along with any household contacts of the returned travellers.
All airline cabin crew arriving from overseas into NSW will also have to isolate for 14 days or until their next departure.
These rules are slightly different in Victoria with vaccinated cabin crew to isolate for 14 days if they had been to one of the nine African countries of concern.
Chief medical officer Paul Kelly said authorities were also in the process of tracking down about 100 Australians who recently arrived from the blacklisted countries and will now need to go into quarantine for two weeks.
Professor Kelly warned it was too early to tell if Australia would be plunged back into lockdown if the virus made its way across the Indian Ocean.
'In terms of ruling in or out, what else we might do, as the health minister has clearly said, we will do what we need to do,' he said on Saturday.
'At this stage, to move toward speculation about where we might end up in Australia, even if it came here, and we don't have it here yet, that is premature.'
He said while little was known about Omicron, it was 'quite different' to previous variants of concern.
'We do not, at this point, have any clear indication that it is more severe, or any definite indication of issues in relation to the vaccine.'
Mr Kelly added that there was too little information about the current variant to make any long-term decisions.
In total, NSW reported 185 new infections on Sunday but for a consecutive day, no new deaths were reported.
In Victoria, 1061 new cases were announced and four more deaths, while there were seven new infections in the ACT.
There were also four new cases detected in the Northern Territory, where the remote community of Lajamanu will stay in lockdown until December 11 after the virus was detected in wastewater.
There were no new infections in South Australia after reporting three on Saturday.
Federal Health Minister Greg Hunt said almost 39.1 million vaccinations have been delivered in Australia.
Some 92.3 per cent of Australians 16 and over have had their first dose, while 86.7 per cent are fully vaccinated.