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Australians are being warned to brace for a fourth COVID-19 wave as multiple states report sharp increases in case numbers following months of relative stability.
On Thursday morning, Queensland Premier Annastacia Palaszczuk announced the state's traffic light system would move from "green" to "amber"as of tomorrow, to reflect an escalating number of patients in hospital and new virus transmissions.
Last week, New South Wales Chief Health Officer Dr Kerry Chant said residents should prepare for case numbers to rise in the coming weeks.
The sentiment has been echoed by other health officials across the country, where rising case numbers have been similarly reported.
But, how worried should we be? Are we in for another COVID-19 Christmas?
Here's everything you need to know, as told by the experts.
Are there new COVID-19 variants/strains?
Yes. The short answer is that there are many new COVID-19 strains circulating in the community that you may or may not have heard about.
Professor Adrian Esterman, Chair of Biostatistics at the University of South Australia, said that not only are there several "new" variants, they're also becoming better at "getting around our immune systems".
"Australia is now in its fourth wave of Omicron infections. However, unlike the previous waves caused by Omicron BA.1, BA.2, and BA.4/5, this wave has several causes," he said.
"The first is waning immunity. Many people have had their last dose of vaccine over six months ago, and by now have comparatively little protection against symptomatic disease. At the same time, we have little or no public health measures in place to put a brake on transmission.
"These new subvariants are more transmissible than BA.5. They include BA.2.75, BQ.1 and XBB."
How many variants of COVID-19 are there in Australia?
Currently, the Omicron BA.1, BA.2, BA.4, BA.5, BA.2.75, BQ.1, BR.2 and XBB are all circulating around the country, with some more transmissible than others.
Experts have branded the new line of strains a "variant soup" and "the grandchildren of Omicron".
"A fourth wave of COVID-19 started in Australia towards the end of October, driven by a 'variant soup' of new lineages of SARS-CoV-2," UNSW's Associate Professor James Wood said.
"Instead of a single variant driving this, we have many lineages with similar properties causing this rise, although the XBB, BQ.1.1 and BR.2 lineages are likely to be most prominent in Australia."
When will the wave peak?
According to Professor Wood, Australia's fourth COVID-19 wave will be short and sharp, similar to what has recently been reported in Singapore.
"I expect that we will see a short sharp wave, similar to the recent one in Singapore with a peak by the end of November," Wood said.
"I also expect this to be smaller than the BA.5 wave but that we will see a considerable rise in hospitalisations and deaths, particularly in people over 65."
The latest COVID-19 strain spreading across the world
What does the COVID-19 traffic light system mean?
The traffic light system is specific to Queensland and reflects the level of caution residents should practice throughout their day-to-day life.
The amber setting means there are "moderate rates of community transmission" and Queensland is "coming off a wave or may be entering a new wave" according to the government's website.
No other state has a specific traffic light system, but health authorities in different states have issued their own similar warnings.
Will restrictions return?
It's not likely right now.
Professor Booy from the University of Sydney said that conditions should be able to be managed relatively easily without the return of harsh restrictions.
"The new COVID wave is a concern," Booy said. "It's due to the grandchildren of Omicron, a variant which has been with us now for a whole year.
"This tells us that the virus is running out of ways to mutate so as to evade our immunity.
"There will undoubtedly be an upsurge in cases but the new wave, I think, will be easily body-surfed by most sensible people.
"Taking those common-sense cautions like vaccination, social distancing, masking in public places, especially if vulnerable; and if infected and also vulnerable due to age or disease, consulting your GP rapidly for potential use of antivirals – these measures will together make a real difference and get those body surfers safely back to shore."
Health officials around the country have yet to officially announce the return of any major restrictions, but many have ruled out future lockdowns and tough protocols seen in 2020 and 2021.
Should I be worried about the fourth COVID-19 wave?
Like many viruses, COVID-19 has the potential to be very unpleasant if you contract it, and is potentially deadly to vulnerable Aussies.
But experts say that new variants aren't "increasing in severity".
"We have seen no evidence of increased severity in international settings," Wood said.
"But age remains a key risk factor and there are many Australians still eligible for third or fourth doses who could benefit from a booster dose at this time."
Associate Professor James Trauer said there's "no need to panic" just yet.
"Overseas, several countries have passed through waves with these newer offshoots of BA.2 and other variants, usually with mild to moderate strain on their healthcare systems," he said.
"So there's no need to panic and it's unlikely we'll need any population-wide restrictions. However, the elderly and at-risk groups should ensure they have had all the vaccine doses they're eligible for."
Should I get a fourth booster?
If you are eligible, experts say yes.
Authorities all collectively agree that where possible, vaccinate.
Vaccines are responsible for saving lives, reducing the severity of illness and hospitalisations and reduce the impact of COVID-19 in the community.
If it has been over six months since your last jab, your protection will now be have been dramatically reduced.
Aussies have been advised to speak to their health practitioner if they think they might be at risk.