What you need to know about COVID-19 today, Wednesday January 13.

NSW still trying to link COVID cases, one new local case.

New South Wales has recorded just one new local coronavirus case on Wednesday, in a child in a household with existing cases.

There were 20,664 tests in the 24 hours to 8pm Tuesday, an increase from 19,000 the day before and closer to health authorities' 25,000 daily goal.

There were six additional cases in returned travellers in hotel quarantine.

Premier Gladys Berejiklian said genomic testing had also found the couple from Mt Druitt, included in Tuesday's numbers after the man presented to Mt Druitt Hospital over the weekend and returned a positive test, have been linked to the Berala cluster.

However, authorities don't yet know how the couple came to be infected.

Of the seven new cases reported to 8pm last night:
- One locally acquired case is linked to the Berala cluster and is a close contact of previously reported cases. There are now 28 cases associated with the Berala cluster.
- Six are returned travellers.

— NSW Health (@NSWHealth) January 13, 2021

Four weeks on from discovering the Northern Beaches outbreak, NSW Health is still trying to link 14 recent cases to known clusters.

The origins of two of Tuesday's cases - one on the northern beaches and one in Blacktown - are so far unknown.

There had been 12 cases found since December 16 that are still being investigated by NSW contact tracers, including three detected before Christmas.

A further two cases - from the Canterbury-Bankstown and Lane Cove council areas - have been fully investigated without any link found.

On Tuesday, NSW Premier Gladys Berejiklian said she backed the contact tracing teams, saying their work allowed her government to make decisions that didn't place "unnecessary burdens" on residents.

"We have the best health contact tracing team in the nation," Berejiklian said.

She said the search to identify the case that sparked the Northern Beaches outbreak wouldn't be stopped.

"We never give up the hunt in NSW," she said.

"Sometimes it might take us hours, sometimes days, or sometimes weeks, but we always get to the bottom of what we think happened, and I'm confident we'll get there.

"But we also have to give our experts time to make those connections."

NSW has more than 200 active coronavirus cases, including one person who is in hospital in intensive care.

Queensland records zero local cases, concerns about UK variant remain.

Queensland has recorded two new coronavirus cases on Wednesday, both in hotel quarantine.

Residents underwent 20,615 tests in the same 24 hour period. In total, Queensland has 26 active cases.

Wednesday, 13 January – coronavirus cases in Queensland:

• 0 new locally acquired cases
• 2 overseas acquired cases
• 26 active cases
• 1,283 total cases
• 1,642,210 tests conducted

Sadly, six Queenslanders with COVID-19 have died. 1,245 patients have recovered.#covid19 pic.twitter.com/j1JKy1ibND

— Annastacia Palaszczuk (@AnnastaciaMP) January 12, 2021

Premier Annastacia Palaszczuk said despite no community spread, authorities were concerned about a UK variant cluster within hotel quarantine at the Grand Chancellor.

"Genomic testing has now linked six cases of the highly infectious UK variant of COVID. These are the UK traveller and his partner, the hotel cleaner and her partner, and the man and his daughter from Lebanon who we told you about yesterday," she explained.

"So all six have a connection to the Grand Chancellor hotel."

Palaszczuk said both groups of infected travellers stayed on the same floor of the hotel at different times but not in neighbouring rooms, leading to immediate actions in the hotel.

"The remaining 129 guests are going to be moved to other hotels and they will be tested. They will not be charged for their time at the Grand Chancellor or in the hotels that they are going to be moved tomorrow.

"226 people who worked in the hotel since December 30 are going to be contacted and they will go into quarantine and get tested. Once again - precautionary.

"250 quarantined guests who have left the hotel since December 30 are now currently being contacted. They will be quarantined and tested. Once again, precautionary. 

"No more guests have gone into the hotel since the variant was discovered on January 7. As you can see, everybody is cooperating, everyone is doing the right thing."

Chief Health Officer Dr Jeannette Young said authorities were currently unsure how a returned traveller with the variant infected a cleaner.

Victoria records week without local COVID case.

Victoria has reached one week without recording a local or interstate acquired case of coronavirus. 

Yesterday 0 new locally acquired cases were reported. There are 3 new cases in hotel quarantine. 17,908 test results were received. Got symptoms? Get tested - #EveryTestHelps. More later: https://t.co/lIUrl0ZEco #COVID19VicData pic.twitter.com/lQsgK365mF

— VicGovDHHS (@VicGovDHHS) January 12, 2021

The Department of Health and Human Services on Wednesday confirmed the state recorded no new locally acquired cases for the seventh day in a row, though there are three cases in hotel quarantine. 

Some 17,908 test results were received in the past 24 hours. 

The state has 35 active cases.

Coalition MPs' virus posts spark backlash.

The Morrison government is under increasing pressure to stop two of its MPs spreading dangerous coronavirus misinformation.

Acting Prime Minister Michael McCormack and Health Minister Greg Hunt have refused to publicly condemn Liberal MP Craig Kelly and the Nationals' George Christensen.

The conservative backbenchers have used Facebook to share conspiracy theories about controversial unproven coronavirus treatments.

The Australian Medical Association is calling on the federal government to launch an advertising campaign against health misinformation.

Doctors demand government call out medical misinformation after acting PM says 'facts are contentious' https://t.co/657dTEVWwR

— Lenore Taylor (@lenoretaylor) January 12, 2021

AMA president Omar Khorshid said people in positions of power could deliver online misinformation which others could easily absorb.

"We have seen this with the anti-vaccination movement and the countless conspiracy theories about the COVID-19 pandemic that circulate constantly on the internet," he said.

Labor has demanded senior cabinet figures condemn the coalition duo who are refusing to take a backward step.

Opposition health spokesman Chris Bowen said Kelly had made a systemic and deliberate attempt to undermine medical health professionals.

"Craig Kelly is a menace and at every turn, Scott Morrison and now Michael McCormack, acting prime minister, have failed to call him out," he said.

Kelly on Tuesday fired off a fresh barrage of posts championing Ivermectin, an unproven coronavirus treatment Facebook warned him over last week.

Scott Morrison under pressure over Craig Kelly, MPs’ far-right Trump claims. George Christensen has a 2020 Trump flag in his Parliament House office window. #auspol https://t.co/kd5k5QWkdc

— 🌏 Zali Steggall MP (@zalisteggall) January 8, 2021

Health Minister Greg Hunt wouldn't be drawn on Kelly's accusation health officials had engaged in child abuse for encouraging face mask use.

"There will be different views from different people," he said.

But Hunt argued Australia's success in combating coronavirus stemmed from governments acting based on expert health recommendations.

"Our advice comes from what I believe are the best medical advisers in the world. That's what's protected Australia and that's what we're going to continue to do," he said.

"I would urge everyone to listen carefully to the advice of the Australian medical regulators and Australian government medical advisers."

Christensen and Kelly have shared material criticising masks and lockdowns, while also promoting hydroxychloroquine as a coronavirus treatment.

McCormack told people railing against Christensen's Facebook posts to "toughen up" and claimed "facts are sometimes contentious".

"You might look out there and say the sky is blue and I can see from here that it's grey. If we go out from this rotunda there are probably blue patches," the Nationals leader said in north Queensland.

"There are a lot of subjective things."

Numbers cut on three repatriation flights.

Australians stranded overseas have been dealt another blow, with passenger numbers halved on three repatriation flights because of new caps on international arrivals.

There are also reports some commercial flights have been abruptly cancelled without explanation.

National cabinet last week resolved to halve incoming passenger caps in NSW, Queensland and Western Australia until mid-February to reduce the risk of exposure to the highly contagious UK strain of coronavirus.

Australians booked on repatriation flights home have been suddenly booted off as a result of national cabinet's decision to temporarily lower the cap on international arrivals | @Gallo_Ways https://t.co/tfK8w0qPRZ

— The Sydney Morning Herald (@smh) January 11, 2021

The Department of Foreign Affairs and Trade has confirmed three flights into Brisbane have been affected.

"Three Australian government facilitated commercial flights arriving in Brisbane in the coming weeks have had their passenger numbers reduced by 50 per cent based on the decision by national cabinet to halve international arrivals from 15 January to 15 February," a departmental spokesman told AAP on Tuesday.

"Numbers on all facilitated flights are restricted by caps as applied by states and territories and agreed by national cabinet."

While the Northern Territory plans to increase its intake of international arrivals over the next few weeks, the overall number of returning Australians will be significantly reduced across the country.

Passengers will also need to return a negative coronavirus test before boarding a flight to Australia.

Around 37,000 Australians stranded overseas have told DFAT they want to return.

More repatriation flights are slated in coming weeks for vulnerable Australians stuck in the UK, India and the US.

Victoria unveils strict Australian Open quarantine plan.

Government officials have moved to assure Victorians that players in next month's Australian Open will be subjected to the strictest quarantine arrangements for a tennis tournament anywhere in the world.

Players have been warned of severe penalties, including possible criminal sanctions, if they or a member of their team break quarantine.

About 1200 players, officials and support staff will be tested for COVID-19 before travelling to Melbourne on 15 charter flights that will arrive from Thursday evening.

Australian Open players face world's 'strictest rules for tennis' amid Covid concerns https://t.co/QtLhNYjCxd

— Guardian Australia (@GuardianAus) January 12, 2021

The participants will quarantine in three Melbourne hotels - the Grand Hyatt, Pullman Albert Park and View Melbourne - for two weeks before the Australian Open begins on February 8.

They will be permitted to leave their hotel rooms for up to five hours a day for training and treatment, in order to reduce the risk of injury, and will do so in a secure training bubble overseen by COVID-19 Quarantine Victoria staff.

Dedicated training venues have been set up at Melbourne Park, the National Tennis Centre and Albert Reserve - each linked to a specific quarantine hotel.

Participants in the training bubbles will only be allowed to access training facilities from day two of their quarantine periods, and only once they have returned a negative coronavirus test.

They will be tested every day while in quarantine.

Once participants have completed quarantine, they will no longer be subjected to mandatory coronavirus testing, unless they display symptoms.

Participants who test positive to COVID-19, as well as anyone identified as a close contact, will be transferred to a health hotel and will not be allowed to take part in the Australian Open until they have returned a negative test result.

Victoria's Police and Emergency Services Minister Lisa Neville told reporters on Tuesday the quarantine program for Australia Open participants is "identical" to that being run at other mandatory quarantine hotels for the general public, with the exception of tennis training provisions.

"We have put in place the strongest and strictest rules that apply for tennis across the world," she said.

Limits to be imposed on crowd numbers at the Australian Open are still yet to be decided.

Meanwhile, the Australian Grand Prix - which also takes place in Melbourne - has been rescheduled from March to November 2021.

US 'to require negative test' for entry

The head of the US Centers for Disease Control and Prevention (CDC) is expected to sign an order expanding coronavirus testing requirements for all international air travellers, not just from the UK, sources briefed on the matter have told Reuters.

The new rules are set to take effect two weeks from the day they are signed, which would be January 26.

CDC has been urgently pressing for an expansion of the requirements with US President Donald Trump's administration for weeks.

One remaining issue is how to address some countries that have limited testing capacity and how the CDC would address travel to those countries, the sources said.

It comes as all major UK supermarkets have finally mandated masks in their stores.

The virus is running rampant in both countries.

-With AAP.

Feature image: Getty.