Health authorities have confirmed 18 cases of coronavirus linked to a special needs school in Sydney's north, with students, their families and staff all in isolation.
NSW Health has confirmed the cases associated with the Giant Steps special education school in Gladesville on Sydney's Lower North Shore, including three staff, seven students and eight family members.
The school caters for students with severe autism.
A NSW Health spokesperson said the first cases were notified on 5 August, the school had been closed and families and staff were isolating.
"NSW Health takes proactive steps to contact all close contacts of the case, to give advice on testing, isolation, symptoms to be aware of, and their level of risk," the spokesperson said in a statement.
Concern for Indigenous populations in western NSW
Meanwhile, NSW Health officials are "very concerned" about the potential spread of COVID-19 among vulnerable communities in the state, with the majority of new cases in Dubbo and Walgett diagnosed in Aboriginal people.
Five cases have been recorded in Dubbo in the past three days, along with another case in western NSW. They include an Aboriginal man from Walgett.
The cases led the state government to call a one-week snap lockdown for the Walgett, Dubbo, Bogan, Bourke, Brewarrina, Coonamble, Gilgandra, Narromine and Warren areas on Wednesday.
Federal Health Minister Greg Hunt on Thursday confirmed an additional 7,680 Pfizer vaccine doses will be provided for the affected areas, including Walgett.
The shots are expected to arrive on Thursday, with 4,800 for use by GPs and commonwealth vaccination clinics, and 2,880 for Aboriginal community-controlled health services.
Mr Hunt said extra AstraZeneca vaccines would also be made available in what is a "whole-of government" effort to support and protect those communities.
Western Local Health District Chief Executive Scott McLachlan confirmed that the "vast majority" of those cases were in Aboriginal people, including children.
"We're very concerned about the Aboriginal population in the region," he told ABC Radio National.
"The last thing we want to see is this Delta strain spreading across the Aboriginal community, so we'll do everything possible to make sure we keep people safe."
The number of cases in the region is expected to grow significantly in the coming days, Mr McLachlan said.
Fuelling concern is a combination of significant Indigenous populations, low vaccination rates and relatively poor health services.
Nearly 30 per cent of people in the Walgett LGA are Aboriginal or Torres Strait Islander, and Dubbo also has a significant Aboriginal population.
NSW Health Minister Brad Hazzard on Thursday acknowledged there had been problems delivering adequate vaccine supplies to Walgett.
"There's still a very substantial percentage, in fact by far the majority of Aboriginal people in that section of our state have not received the vaccine," he said.
Aboriginal communities are hesitant to take the AstraZeneca vaccine because of misinformation on social media, but there is strong demand for Pfizer, he said.
The Dharriwaa Elders Group at Walgett issued an urgent request on Thursday evening for more trained nurses to support Aboriginal Medical Services.
Mr Hazzard admitted those services were understaffed.
The group also requested motel rooms be made available for people who are homeless, accommodation and support for people leaving prison, and mobile testing and vaccination.
