"Unfortunately the gentleman wasn't vaccinated, hadn't had any dose of the vaccine. As we understand the death happened quite suddenly."
Chief health officer Dr Kerry Chant said the man was being cared for by south-western Sydney local health district during his isolation period, and had reached day 13 before he "suddenly deteriorated".
"He was being checked daily and he did complain of feeling a little fatigued but the deterioration happened suddenly," Chant said.
"It is important that we understand that with Covid you can get sudden deaths and I think that is important to understand your health status can deteriorate."
She said the man was living with one other person. "You can imagine the trauma for that other person who has now been hospitalised [with Covid-19]."
In addition to the man in his 20s who died at his south-west Sydney home, a woman in her 80s from the inner west also died at Royal Prince Alfred Hospital yesterday after testing positive for Covid on July 27.
It is understood the woman was unvaccinated.
At least 47 of today's new locally acquired cases were infectious in the community.
"That's the number we are desperate to see reduce," Berejiklian said.
Berejiklian was probed about why some retailers are staying open after NSW Health issued a mammoth list of new exposure sites which were spread across 79 suburbs.
"Obviously the lockdown rules we have in New South Wales are some of the harshest our nation has seen," she said.
"We need people to remember every time they leave the house that they could have the virus or someone they come into contact with could have the virus."
NSW Health has confirmed there have been 4063 locally acquired cases reported since June 16, when the first case in this recent outbreak was reported.
There are currently 286 Covid-19 cases in hospital, with 53 people in intensive care and 23 requiring ventilation.
There were 105,578 Covid-19 tests reported to 8pm last night, compared with the previous day's total of 104,536.
'Biggest outbreak since first wave': Queensland reports 17 new Covid cases
Queensland has recorded 17 new locally acquired Covid-19 cases, bringing total case numbers in the latest outbreak to 63.
Deputy Premier Steven Miles said all were linked to a known cluster.
Four cases are linked to Ironside State School, including one teacher; two cases are linked to Indooroopilly State High School; one case is linked to Brisbane Boys Grammar and nine cases are close contacts or family members of cases already identified in the cluster.
"That brings this outbreak to 63 cases, meaning that in less than a week, this has become our biggest outbreak since the first wave last year," Miles said.
Queensland recorded 16 new community cases yesterday.
A case found yesterday in Cairns - a man who authorities believe was either at the start or beginning of his infection due to his viral load - was still being investigated, Miles said.
"It's confirmed to be the Delta strain but not linked to the current outbreak in Brisbane."
His case triggered warnings for the Cairns, Trinity Beach and Yorkeys Knob areas last night.
Miles said the state was now dealing with 100 active cases, but Queensland's incredibly high testing rates were giving authorities confidence it was beating the outbreak.
"We didn't just break our testing record yesterday, we smashed it, which is a fantastic result," he said.
"Our previous record was 35,357 tests. In the last 24-hour period we tested 51,479 samples, breaking past that record, breaking past that goal that the chief health officer set for us and so let's keep it up, Queensland."
Zero community cases in Victoria
In better news for Victorians, the state today recorded zero locally acquired cases of coronavirus.
Victoria emerged from its fifth lockdown earlier this month due to an outbreak of the Delta strain.
