Coalition for Epidemic Preparedness chair and vaccine expert Jane Halton also said Omicron was here to stay.

"It's arrived and we're now seeing it spreading not just in Sydney but elsewhere," Ms Halton told the Nine Network.

"I think the horse has bolted."

And it looks like she's right.

NSW has recorded 42 Omicron cases as of today - and health authorities are expecting a lot more after five people who attended a boat party tested positive for the variant.

The ACT has recorded Omicron cases, along with Victoria and Queensland.

The Queensland case could be a "world first".

A traveller who recently arrived from South Africa may be the first case carrying a sub-lineage of the Omicron variant, but tests are needed before it can be confirmed or rejected as a new strain.

Luckily the sunshine state reached its 80 per cent vaccine rate today too.

Deputy Prime Minister Barnaby Joyce has tested positive to the virus in the US after travelling from the UK.

"I'm not dying here. I'm feeling like I have a slight-to-mild flu," Joyce, who is fully vaccinated, told Sky News from isolation this morning.

The federal government recently revealed that boosters would be available to those who had the COVID-19 jab six months ago.

And AAP reports that Pfizer says a booster dose of its COVID-19 vaccine increased people's levels of virus-fighting antibodies by 25-fold.

However, a new survey from the Australian National University has found that some people are hesitant to get the booster shot.

The survey also found that residents in states that avoided lockdowns this year were more hesitant to nab a third jab.

"Results confirm that vaccine rates are low in the states and territories that did not experience significant lockdowns during the third wave of COVID-19 infections in Australia," the report said.

Scientists still don't quite know yet just how much of a threat the Omicron variant is, however, the World Health Organisation has said "preliminary evidence suggests an increased risk of reinfection with this variant".

So I guess we'll just have to wait and see.

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