Chief public health officer Professor Nicola Spurrier said authorities noticed late last week that wastewater at Bolivar contained a higher count of COVID-19 than what was being picked up in the community through testing.

She said the disparity could be caused by a drop in the number of people reporting positive rapid antigen tests or seeking PCR tests.

“The signal strength (from wastewater testing) has always been a little bit lower than our actual case numbers, but it’s just swapped over to the end of last week,” she told reporters this afternoon.

“It does make me a bit concerned that there may be cases that are not being picked up in our community.

“We’ll keep monitoring that just to make sure and try ascertain what that means.”

SA Health data shows 6772 people received a PCR test in South Australia yesterday – a 15.3 per cent decrease on the previous 24 hours.

Spurrier said the testing rate “could be a bit higher” and urged more people to get a PCR test if they have COVID symptoms but return a negative rapid antigen test.

“South Australia’s always really got behind when things have got grim and so I’m really just appealing to everybody to keep up that good work,” she said.

“If you’ve got any symptoms at all please just don’t assume it’s just a cold – please get a PCR test done.”

South Australia today reported 4053 new COVID cases – up from 3358 yesterday – but it’s the hospitalisation rate which has authorities most concerned.

The state today hit a new record of 306 patients with COVID in hospitals, including 11 in intensive care.

The previous record was 294 in January.

The system is under pressure, the system is full

Spurrier said she was concerned about the hospitalisation rate given wastewater testing showed a higher prevalence of COVID in the community.

She said authorities were currently managing the strain on the hospital system “day by day”.

“We always find – and this has been the same throughout the pandemic – there’s about a week or two lag in having our case numbers go up to then having our hospital numbers go up, so I suspect it’s (the hospitalisation peak) going to go a bit higher than (306),” she said.

“Obviously, the Minister and all the CEOs of the hospitals have been working closely together to make sure we can manage this as best we can.”

Modelling released by the University of Adelaide earlier this month estimated the current COVID-19 wave would peak tomorrow as the more contagious BA.4 and BA.5 Omicron subvariants take hold in the community.

Asked to clarify the timing of the peak, Spurrier said it was expected “sometime this week”.

“The most we are certain about is that we’re going to get a wave – we’re much less certain about the timing of the peak and the height of the peak,” she said.

“We’ve got 29,106 active cases (and) it was only a couple of weeks’ ago (when) that was down around 16,000, so there are a lot of people out in our community with COVID and are infectious.”

Health Minister Chris Picton said the Royal Adelaide Hospital today opened up a new COVID ward to accommodate infectious patients.

He said hospitals were prepared to open up additional COVID wards, but that meant converting spaces which are currently being used to treat patients with other medical conditions.

“The system is under pressure, the system is full and we’ve opened up as much extra beds as we possibly can across the system,” he said.

“The last I heard this morning was we’re getting more patients into Gawler Hospital, Strathalbyn Hospital today to help free up some of that capacity.

“This clearly shows the importance of taking every measure possible – getting vaccinated, using antivirals, taking preventative measures such as social distancing, testing, wearing masks to ensure we reduce pressure on our health services.”

It comes ahead of an Emergency Management Council meeting tomorrow morning.

Authorities are set to discuss updated modelling, the hospital system, whether masks should be mandated in schools for the start of Term 3 and elective surgery proposals.

The government today announced it had expanded a virtual care service run by the Women’s and Children’s Hospital which allows young patients with moderate illness to be treated at home.

The service is aimed at children with respiratory symptoms, including RSV (respiratory syncytial virus), and can be accessed through a hospital referral or virtual assessment.