The Delta outbreak that was discovered at the end of last week, and prompted a lockdown that has already been extended to Sunday, is growing more rapidly. After 13 cases were reported yesterday, another 16 were reported today.

At least nine of the 16 are children, one is a teacher, while another new case is a neighbour of a family with the Delta variant in the household. Thankfully, all have so far been linked to known cases, but Chief Health Officer Jeannette Young is still investigating how the virus was carried from one of two returned travellers last month.

The outbreak is now spreading via unvaccinated and unmasked children, and already closed Indooroopilly State High School and Ironside State School, with exposure sites at various shopping centres, sporting venues, cafes and halls.

Other cases have popped up at private schools, including Brisbane Grammar, and students in the 11 council areas subject to the lockdown are now learning remotely. Children of essential workers can still attend school but with only a skeleton staff.

With more than 4,000 people now in home quarantine, awaiting test results that will give them the all-clear, the outbreak and associated restrictions are having a broader flow-on affect – at least 400 health workers can no longer see patients, causing problems in the health system itself.

Chief Health Officer Jeannette Young said she started making contingency plans last night, including one emergency work-around.

“All of our cardiac surgeons for the (Queensland) Children’s Hospital were in quarantine so we worked through how we could allow one of them to go and operate on an urgent case,” Young said.

“And we will do that every single time.”

Young said even those vaccinated could still potentially pass on the virus to patients and staff, and she did not want to close health services completely.

New data shows Brisbane’s west has the highest rate of vaccination in Queensland – 24.5 per cent of those aged over 15 and eligible have had both doses, compared to only 10.2 per cent in the Mackay-Isaac-Whitsunday region.

Young implored eligible Queenslanders to complete their vaccinations, and urged grandparents of the affected students to stay away unless they have had both doses.

“We still don’t have all of our healthcare workers and aged care workers vaccinated, we need them all vaccinated,” Young said.

She reiterated Queensland had AstraZeneca available for older people and, for the first time, said the outbreak was “on the verge” of being so significant it should warrant younger people considering AstraZeneca rather than wait for Pfizer.

Having previously, repeatedly, urged young people to hold out for Pfizer, Young said it was time for anyone concerned they might contract COVID-19 to ask their GP “what is best for them as an individual”.

“The ATAGI advice says when you reach a large outbreak, which I think we’re on the verge of – I hope it doesn’t become any longer but I suspect it will – that then that is the time to go and have that discussion with your GP,” Young said.

ATAGI also recommends the time between AstraZeneca doses be shortened in an outbreak, something Young will herself do when she gets her second jab this week.

To lift the lockdown as scheduled, at 4pm on Sunday, Young would require all new cases to have been in quarantine while infectious. That will require a massive contact tracing effort, even more people being placed in hotel quarantine, and an unprecedented level of testing.

New testing sites are being established – a centre at Indooroopilly State High School is for the school community alone – and Queensland is expected to break its record of around 35,000 tests in 24-hours, and close in on Young’s target of 40,000 daily tests.

There is still concern that the virus may be spreading undetected on the Sunshine Coast, so extra testing is being arranged for targeted communities including schools. Young said she had new testing results that gave her hope there might be fewer missing links between the two returned travellers with Delta and the first Indooroopilly household.

While the number of cases in the outbreak hit 31 yesterday, and increased again overnight, the official list of exposure sites has only been gradually updated, with contact tracers busy trying to make connections.

This morning, Queensland Health pointed to new sites in Springfield Central, Pullenvale, Woolloongabba, Sunnybank, Brisbane City and Southport. Popular places at the University of Queensland (which has closed its St Lucia campus), Indooroopilly Shopping Centre, community sport and religious centres are among the sites.

Young had called on all office workers to go home, and for shops to close if not providing an essential service. Today, she made a point of saying Cotton On and JB HiFi were “not essential to me” and she expected them to make a decision about closing.

Police are enforcing the restrictions but Deputy Commissioner Steve Gollschewski reiterated his concern that a minority of people felt the need to ignore or even protest the rules. His comments followed more arrests in Brisbane yesterday.

“I feel really, really worried that we won’t be able to get on top of this because there’s a small percentage of people who continually put their own interests ahead of their whole community,” Gollschewski told ABC Radio.

Health Minister Yvette D’Ath welcomed a Commonwealth offer of another 150,000 doses of AstraZeneca to help vaccinate those most at risk. She said it would be put to good use by pharmacies but could only go so far, as Queensland Health was focussed on distributing Pfizer to frontline workers and the eligible 40-60 year age group.

“What Queensland needs more than anything else is additional Pfizer supply,” D’Ath said.

“Queensland Health can rapidly increase its Pfizer vaccinations, provided the Morrison government can get us more supply.”

D’Ath had previously requested more Pfizer, only to be offered AstraZeneca to be distributed to Queensland pharmacies and GPs. She has now asked for August allocations to be brought forward to deliver another 84,000 Pfizer doses each week.

Meanwhile, Premier Annastacia Palaszczuk, who is in hotel quarantine, released a styled and edited social media post on how “with all of us working together, it will never defeat us” – only to be ridiculed for not including vaccination among her tips for Queenslanders to survive lockdown.