A man in his 20s died “suddenly” from COVID-19 at his Sydney home as NSW recorded 233 new infections and Premier Gladys Berejiklian warned the Delta outbreak would get worse.

Key points:

The man had no underlying health conditions and died at his home in Sydney’s south-west yesterday.

He was being checked daily by staff from the South Western Sydney Local Health District (LHD), but chief health officer Kerry Chant said his condition “suddenly deteriorated”.

“He did complain of feeling a little fatigued but the deterioration happened suddenly is my understanding,” Dr Chant said.

“We are aware that with COVID you can get sudden deaths and I think that is important to understand that your health status can deteriorate and you can have sudden death with COVID.”

The man, who wasn’t vaccinated, was living with one other person who also has COVID-19 and has since been admitted to hospital.

“You can imagine the trauma for that person who has now been hospitalised,” Dr Chant said.

Dr Chant said the man had been battling COVID for about 13 days.

A woman in her 80s from Sydney’s inner west also died yesterday after testing positive to COVID-19 on July 27.

She died at the Royal Prince Alfred Hospital and was not vaccinated.

The death toll in NSW since the pandemic began is now 73.

Ms Berejiklian today backtracked on an announcement she made last week about Year 12 students returning to school on August 16, and suggested some may have to stay home for longer.

“We will provide confirmation of our plans for Year 12 moving forward later this week or early next week and I want to make it clear that we will not support any initiative that will worsen the situation or become a health risk,” she said.

“I do want to foreshadow that given where the case numbers are at, especially in those eight local government areas and students won’t be vaccinated until the week of 9 August, that we need to make sure we adjust our policies according to what’s happening.”

But Ms Berejiklian said it wouldn’t be a “uniform” approach and it’s likely students in some areas — such as Shellharbour, Wollongong and the Central Coast — would be able to return to campus.

“I don’t want to make any of those comments until we have further information [but] I want to stress the following … all Year 12 students will get their HSC.”

Ms Berejiklian said the large number of infectious cases in the community suggested the outbreak had not reached its peak yet.

“We will turn the corner it’s just a question of when,” Ms Berejiklian said.

Of the new cases reported yesterday, 47 were infectious in the community and 21 were in isolation for only part of their infectious period.

The isolation status of 73 cases remains under investigation.

Of the 233 new cases, 93 were from South Western Sydney LHD, 65 are from Western Sydney LHD and 54 are from Sydney LHD.

Where the new cases are located:

Fragments of COVID-19 have been found in sewage treatment plants around Newcastle and the Central Coast.

Dr Chant said people in those areas should be on high alert for virus symptoms and said the suburbs of most concern were Birmingham Gardens, Shortland, Maryland, Fletcher, Minmi, Cameron Park, Mayfield, Stockton and Fern Bay.

“It is critical that we can get those testing levels up to really understand as soon as possible whether there is any undiagnosed cases there so we can make the best public health decisions,” she said.

There were 105,578 tests in 24 hours to 8:00pm yesterday.