Another positive case was recorded when a man who works as a consular official flew into Queensland from Afghanistan, via Sydney, and was allowed to quarantine at his home on the Sunshine Coast.
The state’s Chief Health Officer Jeannette Young was cautiously optimistic on Monday announcing no new cases in the previous 24 hours, but sounded a note of caution.
“The next week remains critical. We know it’s now eight days since those first two cases who went to Melbourne and returned have been out in the community,” Dr Young said.
“We know that one case, if it’s out and about in the community, could rapidly lead to a lot more cases, so it’s time to be really vigilant.”
Griffith University emergency medicine expert Lara Herrero said seeing no new cases was a positive sign, but the next week would be critical in gauging if the virus cluster had taken hold.
“The incubation period can be different in different people, there are all sorts of factors at play there,” Dr Herrero said.
“[The lack of new cases] is definitely a positive sign, it indicates to me that in some of these areas people are still social distancing like they should be.”
Experts consider the lack of new cases remarkable, given the range of places the two women who tested positive visited while potentially infectious, ranging from Brisbane’s south, to northern Logan and Springfield.
One of the two women infected her sister, while a couple who visited the same restaurant as them also became infected, however that branch of the cluster also appears contained at this stage.
UQ public health physician and infectious diseases expert Linda Selvey said there could be other cases waiting to be discovered, but the high rates of testing already done gave Queensland a good chance to get ahead of the cluster.
“We’re not out of the woods yet, there still may be other cases that we are unaware of, and we still need more time before we can fully say that those recent transmissions haven’t resulted in further cases,” Dr Selvey said.
“In a situation where you’ve got good social distancing and so on, you wouldn’t expect any subsequent cases, so it’s good that that appears to be the case in this situation.”
The current cluster has prompted the lockdown of all aged-care facilities in the affected areas, with one of the people from the restaurant who tested positive working at the Bolton Clarke aged-care facility in Pinjarra Hills.
All 105 residents of that facility have tested negative for COVID-19.
Since Thursday, health authorities have conducted more than 50,000 tests and contact traced more than 1500 people related to the women and the consular official.
“Our contact tracing has progressed well over the weekend, there are now just 10 remaining contacts outstanding and our teams will continue to work to contact those people,” Health Minister Steven Miles said.
Queenslanders are being urged to continue good social-distancing measures and to wash their hands regularly.
Mask use is not mandatory, although some businesses, notably Woolworths, have advised people to wear them inside their stores in the areas of south-east Queensland associated with the cluster.
“Mask use isn’t really necessary in Queensland at the moment. If we were to see ourselves start to head down a path similar to NSW or even Victoria then it might be more useful,” Dr Herrero said.
“The message here is to just do the right thing for yourself and your fellow Australians.”
Stuart Layt covers health, science and technology for the Brisbane Times. He was formerly the Queensland political reporter for AAP.