Two new cases of COVID-19 were confirmed overnight, one an aged care worker at Laidley. Both are aged in their 30s, known to each other, and their infections are thought to be connected to the existing clusters at the Brisbane Youth Detention Centre and corrective services training facility.

Those clusters are thought to have originated with the Logan cluster, that followed an ill-fated trip by three women to Melbourne. Much of southeast Queensland has faced additional restrictions as a result of the recent spread of COVID-19, and that Melbourne trip could still have an impact on plans for the Gabba to host the AFL grand final.

Deputy Premier Steven Miles said he was reassured by the fact there were only a few cases each day and a high level of testing. Queensland on Thursday had 30 active cases, the vast majority linked to those clusters.

“That’s really promising, it suggests that our efforts, that our rapid response, is working,” Miles said.

Chief Health Officer Jeannette Young said Queenslanders had adhered to the restrictions, and backed the health sector response.

“We’re starting to see, two weeks into this cluster, that we’ve got control,” Young said.

“It’s too early to say we’ve solved it, we’ve still got a long, long way to go.”

In an unusual development, Young said wastewater testing in Airlie Beach two weeks ago “came up potentially positive” for traces of the coronavirus. It was part of a broader pilot program being run in conjunction with the University of Queensland and the CSIRO.

“It’s very early days for sewage testing, we’re not quite sure what it means,” Young said.

While Airlie Beach is a popular tourist destination, Young noted that some ships moored offshore had COVID-19 cases and it was too early to know the connection.

“But it doesn’t really matter, the response Is the important thing,” Young said.

Young said the plans made for Brisbane to host the AFL Grand Final were based on conditions before the recent cluster. She expressed confidence, however, that 30,000 people could attend the event at the Gabba on October 24, subject to a revised COVIDSafe plan and with hundreds of officials and staff from Melbourne required to quarantine in a hotel organised and funded by the AFL.

Under current arrangements, 20,000 people can attend sporting events in major stadia in Queensland. Young said the AFL grand final was considered “an important event” that needed to go ahead and was worthy of additional consideration.

“That 30,000 is not an absolute given today; the 20,000 is, unless, of course, we had a complete disaster in terms of case numbers,” Young said.

“I’m very hopeful that we’d be able to go up to that 30,000.”

Miles said the economic benefit of Queensland hosting the event, including from tourism promotion around the world, outweighed the economic cost of hosting it. He was confident it would be made safe.

Young has come under pressure over the exemptions process for people to cross the Queensland border and, in some casesm avoid hotel quarantine. Asked if the Queensland-NSW border restrictions might be eased before October 24, Young said NSW would still require two incubation periods, or 28 days, with no community transmission. NSW had only one such case on Wednesday “so they are getting there,” she said.

Young denied there were double standards in who was allowed to enter Queensland.

“No, it’s the one standard, it’s done by a team that I manage, and the standard is that we keep Queenslanders safe,” she said.

Ahead of Father’s Day on Sunday, Young suggested people avoid hugging vulnerable or much older family members if they did not live in the same household.

“Join in groups of up to 10, but be really careful of the more vulnerable people,” Young said.