There were 3261 cases in the latest data published on Friday, compared to 4954 new infections a week ago.

The number of infectious people in hospital also dropped from 185 to 128, including six in intensive care.

SA Health reported that another 38 people aged in their 60s to 90s died after testing COVID-positive, including one person aged under 70.

According to the data, there is still a mixed group of sub-variants circulating within the community, with BA.5 and related variants the most common.

The new XBB.1.5 omicron subvariant, which has so far been detected in more than 25 countries including eight cases in Australia, was detected in 1.5 per cent of samples analysed in South Australia. 

Nationally, daily positive tests are on the decline, with PCR testing dropping by 23 per cent in South Australia on the past week.

As of January 10, the average daily cases were 26.9 per cent lower than the week before, with significant reductions in every state and territory.

Hospitalisations and intensive care admissions are also down, declining 9.3 per cent and 13.3 per cent respectively.

Also this week, a study by Israeli researchers found most people affected by long COVID showed no symptoms after a year.

The study by KI Research Institute and published in medical journal BMJ, suggests patients with mild COVID-19 have an increased risk for a small number of health outcomes, most of which resolve within a year from diagnosis.

– with AAP