Mr Marshall urged parents to get their children vaccinated, particularly before the return of face-to-face study in schools.
He added there were over 10,000 free appointments in South Australian vaccination clinics.
Mr Marshall added those deemed close contacts of COVID-19 cases should get a PCR test to curb the spread of COVID-19.
“It’s far more sensitive and accurate than the rapid antigen tests,” he said.
“There are now no lines for PCR testing in South Australia.”