South Australian health authorities have declared Adelaide’s worst coronavirus cluster is over, with the Parafield outbreak officially eliminated.

But they say the cluster of COVID-19 cases in Sydney remains a concern and no changes to the border restrictions are planned over the holiday period.

With no new cases reported in South Australia on Wednesday, the Parafield cluster has passed 28 days, or two incubation cycles, since the last infection.

The cluster was discovered when an elderly woman at the Lyell McEwin Hospital in Adelaide’s north tested positive on November 14.

It was soon linked back to a cleaner and a security guard at the Peppers medi-hotel, as well as the Woodville Pizza Bar.

Thirty-three people tested positive as a result of the outbreak, which temporarily sent the state into the nation’s strictest lockdown.

The last locally acquired case was announced by SA Health on November 26, while another two cases in people already in hotel quarantine were revealed on November 28.

Chief Public Health Officer Nicola Spurrier said the 28-day period dated back to when the last person was put into quarantine.

“We have officially signed off the Parafield cluster as closed,” Professor Spurrier said.

“It’s been 28 days now since the last active case of the Parafield cluster went into isolation, so it’s a great day, and I’m so pleased it has occurred just before Christmas.”

“It is very nice to be standing out in the sun today and to be able to tell South Australians that we’ve got through it.

“We’ve all done a good job and we can have a fairly unrestricted Christmas.”

Health Minister Stephen Wade this morning said the official end of the cluster was a “significant event”.

“It is a tribute to the public health team and to the people of South Australia and the hard work that’s been done that we are able today to celebrate the closure of the Parafield cluster,” he said.

“The threat has not gone. We now face, at a distance, the threat of the Northern Beaches.”

At its height, the cluster sent more than 5,000 people into quarantine and prompted South Australian authorities to call an intense but short-lived lockdown.

A review has found poor ventilation in the hotel’s corridor was likely responsible for the outbreak.

From today, masks will no longer be mandatory for health workers, including those in aged care, and people working in personal care services such as hairdressers, beauty salons and tattoo parlours.

However, Professor Spurrier said Sydney’s outbreak was a “very active problem” that still posed a threat to South Australia.

Under current arrangements, people from Sydney’s Northern Beaches region are not allowed to enter South Australia, while the greater Sydney region, along with the Central Coast and the Wollongong areas, have been declared high community transition zones.

Anyone arriving from those areas needs to quarantine in a suitable location for 14 days and get tested on day one, day five and day 12.

“We will continue to have that border arrangement for some time, as we see how things play out over the coming week,” Professor Spurrier said.

Mr Wade said more than 1 million mobile phones in South Australia were now registered for QR code check-ins at businesses across the state.

“New South Wales is demonstrating how important that QR code data is,” he said.

The border measures caused some confusion on Sunday when about 550 people, who arrived before a midnight deadline, were wrongly told they had to isolate for two weeks.

Officials confirmed on Wednesday all those people had now be contacted and all but 35 had been released from their quarantine requirements.

People inconvenienced or out-of-pocket because of the bungle have been invited to contact SA Health to seek compensation through ex gratia payments.

Mr Wade said 18 applications had been made so far with each being considered on a case-by-case basis.

-with agencies