Urgent analysis is under way after two passengers from southern Africa who arrived in Sydney tested positive for Covid-19 amid concerns Omicron is already here.

Urgent genomic sequencing is underway after passengers who arrived in Australia from southern Africa last night tested positive for Covid-19.

There are concerns they may be infected with the new variant of concern, Omicron.

Two travellers tested positive after arriving on Qatar Airways flight QR908 from Doha which arrived in Sydney about 7pm on Saturday.

The infected passengers have been transported to special health accommodation where they will undertake 14 days of quarantine.

Fourteen passengers on the flight were from one of the nine southern African countries of South Africa, Lesotho, Botswana, Zimbabwe, Mozambique, Namibia, Eswatini, Malawi, and the Seychelles where the goivernment has put extra restrictiosn in place.

Other passengers on the flight may be considered a close contact and will be contacted and requested to get tested immediately and isolate for 14 days.

NSW Health said close contacts would be contacted regularly and compliance checks would be undertaken to make sure they were following the rules.

Concern Omicron could already be in Australia

While there have been no confirmed cases of the Omicron variant detected in Australia as yet, authorities are also waiting on test results of a positive covid case who recently returned from South Africa on a flight into Darwin.

The person was one of 20 repatriated Aussies completing quarantine in the Northern Territory’s Howard Springs facility.

Health Minister Greg Hunt said he had spoken to his Northern Territory counterpart and was eager to determine the specifics of the new case.

It comes as authorities work to track down at least 100 Australians who recently arrived in the country from the nine African nations without quarantine – as is the new norm in NSW, Victoria and the ACT.

Those people will need to be tested, and quarantine immediately for 14 days from their arrival.

Chief medical officer Professor Paul Kelly said he had been in touch with his state counterparts to enlist their help in mitigating any risk of outbreak.

Mr Hunt said the closing of Australia’s borders to nonresidents from southern Africa, and the isolating of anyone who had recently arrived, was “early, precautious” action.

The Omicron variant, dubbed a “variant of concern” by the World Health Organisation on Friday, has a number of mutations that could make it more infectious than the Delta outbreak.

Authorities are racing to understand the strain, and are considering whether vaccine efficacy will be reduced on this variant.

Prof Kelly said at the moment, the global understanding was that it was “quite different” to previous variants of concern.

“But at this point, other than understanding that it is transmissible between humans and is transmitting particularly in South Africa and those surrounding countries, we do not have any clear indication that it is more severe, or any definite indication of issues in relation to the vaccine,” he said.

Will existing vaccines work against Omicron

The Omicron variant has more than 30 mutations on its spike protein which is more than double carried by Delta, making it a particular concern for scientists.

Such a significant change has raised doubt antibodies created from previous covid infections or vaccination would be enough to protect the person from becoming ill.

Scientists, while still feverishly trying to learn more about the new variant, so far have predicted Omicron will be more likely to infect or reinfect people who have immunity to previous variants.

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