After some 650 contacts of three recent cases were tested and cleared, Chief Health Officer Jeannette Young said investigations into the cause of the mini-outbreak had drawn a blank.

While it was suspected the virus had leaked out of one hotel room on the first floor, and travelled down the corridor to another, infection control processes had been followed and CCTV footage showed nothing unusual.

Similarly, while one of the returned travellers then infected a doctor at the hospital, that doctor had been wearing protective equipment and there was no obvious point of failure.

“I think it’s a wicked virus, I genuinely do,” Young said.

“This is the virus that’s the problem, it’s not any human behaviour.”

Young said Australia had to be prepared for more outbreaks: NSW had also seen the virus leak out of hotel quarantine, and the only reason Victoria hadn’t was because the state wasn’t taking in returned travellers.

She said Queensland could protect itself if everyone kept using sign-in apps, and sought medical attention at the first sign of any problem. The response to the hotel and quarantine cases had avoided the need for another Brisbane lockdown and allowed restrictions on visits to hospitals, aged care, disability services and prisons to be lifted at midday today.

Queensland has a policy of transferring any infected travellers from hotel quarantine to hospital. While Premier Annastacia Palaszczuk has called on the Commonwealth to support an isolated and self-contained quarantine facility proposed for Toowoomba, she today also foreshadowed a time when hospitals would not be able to cope with the influx of patients.

Young says authorities will only lock down the most vulnerable people in future.

She says a focused lockdown of Brisbane’s hospitals, aged care homes, prisons and disability services has stopped the spread after a doctor became infected last week.

“I hope people plan on going and visiting their loved ones in aged care, their family in our prisons, those people in disability services, and hospitals,” Young told reporters.

Young said after 12 months of practice everyone knows exactly how to respond to outbreaks.

People and venues were now habitually using contact-tracing apps, meaning close contacts of virus cases can be rapidly tracked down as well.

She said the success of the focused lockdown meant there won’t be another city-wide lockdown of Brisbane residents.

“Absolutely, there’s no need to go into lockdown when we’ve got responses like this,” Young said.

“We’ve handled it beautifully, absolutely beautifully.”