News of NSW's new Covid-19 cluster has been met with outrage from some health experts as more questions around the exact circumstances of the outbreak arise.
There are now three confirmed cases linked to the cluster in Sydney's eastern suburbs.
The first infection was detected on Tuesday and is a man in his 60s who works as a driver transporting international aircrew from the airport to hotel quarantine. His wife also tested positive to the virus.
The aircrew driver has been diagnosed with the highly infectious Delta strain and the genomic sequencing on his virus matches one from the US.
On Thursday, government health authorities confirmed a woman in her 70s had also contracted the virus after visiting a cafe in Vaucluse at the same time as the driver.
Another case, a man from Baulkham Hills in Sydney's northwest, was also found. Authorities noted the man had "low virus levels", leading them to conduct further tests to determine if the case was a false positive.
Questions have been raised over why the driver wasn't vaccinated and whether necessary infection controls were in place while he was transporting the international aircrews.
All drivers transporting international aircrew are required to be tested for coronavirus every day, however it was revealed the driver's first time being tested was on June 15.
This has left NSW health authorities frantically "putting the pieces of the puzzle together", prompting others to question whether the current infection controls were enough to protect the community.
Biomedical scientist Dr Darren Sauders, said it was "dumb and reckless" for frontline workers not to be vaccinated yet. Saunders said workers shouldn't be let into the quarantine system until they have been vaccinated.
University of NSW epidemiologist Mary Louise McLaws questioned why the aircrew driver wasn't under the same type of infection control as hotel quarantine workers, saying "we should consider this infection as a serious breach" of infection control.
"This man should have been constantly tested with a rapid Antigen test at the airport because he was driving and transporting crews," McLaws told the Australian.
"I find it perplexing that this hasn't been happening to people who are transporting others in vehicles from airports."
Vaccines not mandatory for quarantine drivers
NSW Health Minister Brad Hazzard said being vaccinated against Covid-19 isn't a requirement for the drivers who transport international aircrews to and from quarantine, despite the risks associated with the role.
Hazzard said making the vaccination mandatory could lead to a shortage of drivers.
"There has never been a mandatory requirement for vaccinations for drivers but we have certainly been doing all we can to get people vaccinated in the entire quarantine... system. The issue has been with drivers, there is no capacity to force them to do it," he told reporters.
"It's been a tricky one, because the industry itself is saying that if you force them … to have mandatory vaccinations, there may well be a shortage of drivers because some of them will just say 'nope, not doing it'."
Hazzard confirmed the drivers are required to take a daily saliva test but said authorities are looking into why this driver only had his first test on June 15.
He refused to confirm whether the driver was wearing a mask when transporting the aircrews, saying NSW Police would investigate whether any infection controls has been breached.
"I will say this, every driver is required by our health orders to wear masks at the airport and it would be very unfortunate if you were not wearing a mask. I am not going to comment specifically on whether he did or he didn't," he said.
"If they are driving people, there is an order requiring that they wear a mask. The message I guess more broadly is, if you're involved in this system and you're in the private sector, for heaven's sakes, comply with the law because you may end up causing all sorts of grief."
New case stumps authorities
The fourth Covid-19 case announced on Thursday, detected in Baulkham Hills, had left authorities scratching their heads after initially thinking it may have been a false positive.
The man in his 40s tested positive to the virus, though authorities found he had "low viral levels" prompting an investigation into whether it was a truly positive case.
He is not linked to any known cases but an expert review panel was "unable to rule out the possibility the person had Covid-19".
The man's three household contacts have all returned negative results to date.
The revelation comes after Hazzard told reporters the situation around the case was "looking very good".
Sydney residents, especially those in the eastern suburbs, have been urged to go and get tested even if they have the mildest of symptoms.
While Premier Gladys Berejiklian announced no new restrictions on Thursday, she did urge residents not to become complacent.
"Assume that everybody you're in contact with has the virus and assume you have the virus yourself and that's the best advice we can give you as the next few days unfold," she said.