St Francis Xavier's College at Hamilton is closed for deep cleaning after a student at the school tested positive.
The SFX student, a close relative of a 15-year-old St Pius X Adamstown pupil who tested positive earlier in the week, returned a positive test on Thursday evening.
Hunter New England Health is continuing to investigate the source of infection for all three cases.
It said anyone who attended SFX on Monday, Tuesday or Wednesday should be on the lookout for COVID-19 symptoms and get tested immediately should any respiratory symptoms or fever occur.
"All close contacts of the teenager are being notified and are required to seek testing and isolate for 14 days, regardless of their test result," HNEH said in a statement.
SFX is a senior Catholic college for year 11 and year 12 students, with 941 students and 125 staff.
The school notified parents of the positive test via email on Thursday night and said the campus would be closed on Friday.
"NSW Health will be directly in contact to provide advice to any students or staff identified as a close contact," principal Greg Ptolemy wrote.
"All students and staff are required by NSW Health to self-isolate until you are notified that you are not a close contact."
A Diocese of Maitland-Newcastle spokesperson said "the safety and wellbeing of our staff and students is of paramount importance and we will continue to work closely with NSW Health to ensure all necessary health advice is adhered to".
A third relative of the 15-year-old, a 20-year-old man, visited several Newcastle nightspots last weekend and attended the Jets game against Western United before testing positive.
St Pius is closed for cleaning at least until the weekend.
"The source of infection of the Newcastle family cluster is still unknown, so it is vital people in the community continue to present for testing if experiencing symptoms to limit the spread of the virus," HNEH public health controller Dr Kat Taylor said.
"I encourage everyone to follow directions they receive about home isolation and quarantine and maintain COVID-safe practices of physical distancing, coughing or sneezing into their elbow, and regularly washing their hands."
EARLIER: Aged care facilities in the Hunter have been advised to lockdown "effective immediately" following new cases of COVID-19 in the Newcastle community.
Staff at Newcastle and Lake Macquarie aged care facilities have said they had been advised by the NSW Public Health Unit to close to all visitors for at least the next seven days after community transmissions of coronavirus.
Related to this issue: St Pius X confirmed case has 140 close contacts
The Hunter remains on high alert after two positive tests forced the closure of a Newcastle high school, hotels, and a restaurant for cleaning - prompting hundreds of residents to rush to get tested.
There are now 10 confirmed, active cases in the region, bringing the Hunter's total number of cases to 296.
There were 12 new cases recorded in NSW in the 24 hours to 8pm on Wednesday.
St Pius X High School at Adamstown has been closed for deep cleaning since a 15-year-old student tested positive for COVID-19 on Wednesday.
As investigations into how the Newcastle soccer player contracted the virus continued on Thursday, public health officials confirmed the case's 20-year-old brother had also tested positive.
Contact tracing efforts have since determined the latest case attended seven Hunter venues while infectious.
Hunter New England Health is urging anyone who attended the Bennett Hotel in Hamilton on Friday, July 31, from 5.30pm to 10pm to immediately self-isolate and seek testing.
Those who attended Bar 88 at Wests New Lambton on Sunday, August 2, from 5pm to 7.15pm, and the Sydney Junction Hotel on Saturday, August 1, from 11pm until 1.15am on August 2, were also asked to isolate and get tested.
Hunter New England Health is also urging any patrons who visited the Greenroof Bar and Restaurant in Hamilton on Friday, July 31, from 10.30pm to 12.15am to be alert for symptoms, and get tested and self-isolate if they develop. The same advice was given for people who attended Sushi Revolution, Hamilton, on Saturday August 1 from noon until 12.45pm; Queens Wharf Hotel on August 1 from 9.30pm to 11pm; and McDonald Jones Stadium on Sunday, August 2, from 7.30pm until the end of the Newcastle Jets game.
Queens Wharf licencee Steve Smyth said he called Triple Zero on Thursday morning to clarify the situation after his staff found out about the case's visit through social media.
"Everyone had heard of it before we were contacted by any authority," Mr Smyth said.
He said he had been advised cleaning was not required but proceeded immediately as a precaution.
"I've got a duty of care to all my staff and customers," he said. "It's money well spent. It puts everyone's minds at ease."
Dr Kat Taylor, Hunter New England Health public health controller for the COVID-19 response, said they were still trying to track down the source of infection for the 15-year-old case.
"He was potentially infectious while playing soccer in Sydney - that's why both of the teams have been identified as close contacts," Dr Taylor said. "In terms of a walk-back investigation, when we try to work out where somebody picked it up from, we take it from the time they developed symptoms and go back 14 days, which covers the incubation period.
"Interestingly, the Sydney game also falls into that 14-day period, so it is also possible he may have contracted it from the game.
"We are still trying to work out the relationships."
Dr Taylor's advice to the community was to avoid all non-essential travel to Sydney.
"It seems as though it is really on our doorstep now, so it is really a matter of people trying to crackdown on what they can do to really limit community transmission," she said. "That means thinking about whether they need to make that trip out, or go to that social gathering - those sorts of things, and certainly isolating themselves if they have any symptoms."
Dr Taylor said there were no plans to close any other schools for cleaning yet.
"In terms of the risk posed by a venue, and in terms of where cleaning is required, it is only when a case has spent a prolonged period at the venue - so longer than two hours, and Hunter New England Health does do a risk assessment based on specific venue locations for each situation," she said.
"In terms of risk of people who attend other associated schools - the case was never on those campuses, so we are really only looking at people who have been in direct contact with that person."
Dr Taylor said the public health team was "going hard" on identified venues as a precaution in an attempt to prevent a lockdown.
"By erring on the side of caution of who we consider close contacts, we are really trying to avoid more wide-scale lockdowns," she said.
"We are doing all we can to contain, because we understand from the Victorian situation and ongoing Sydney situation that this virus can get out of hand very quickly if given any kind of breathing room.
"So we have enhanced our responses over the past week to be more stringent on venues attended by confirmed cases."
Dr Taylor said contact tracing and isolating contacts was about "ring-fencing" the infection.
"So that if those contacts go on to get sick, they have limited contact with others. It is really stopping that next generation of transmission," she said.
"The key thing is if you have been identified as a potential close contact of a case, please do your bit and isolate for the full 14 days. Even if you are tested and it comes back negative, you still need to wait out that full 14-day period to allow adequate time for the virus to show itself."
Dr Taylor said anyone with any respiratory symptoms - a sore throat, cough, runny nose, unexplained fever or a change in sense of taste and smell - should get tested for COVID-19. She reminded people to be vigilant about hygiene practices, avoid touching the face, and keep at a distance from others.
She expected there would be a higher demand for testing due to the recent venue announcements, and thanked the community for its patience.
"Even though you can be swabbed in less than a minute, it can take time to move through the queue," Dr Taylor said.
The recent cases of COVID-19 were a "regional issue" given students from St Pius X live across the greater Newcastle and Lake Macquarie area, Charlestown MP Jodie Harrison said.
She said another point of concern was the students who played for the under-15 Jets side, who come from multiple schools.
Ms Harrison is calling for masks to be mandated rather than "strongly encouraged" in order to limit further community transmission.
"Obviously having a school closed as a result of a student testing positive to COVID is concerning," Ms Harrison said. "The school takes students from all over the area - it's not just a local school, so this is a regional issue.
"If masks were mandated, the risk of transmission would certainly be reduced."
While you're with us, did you know the Newcastle Herald offers breaking news alerts, daily email newsletters and more? Keep up to date with all the local news - sign up here
- IN THE NEWS:
- Hamilton's Greenroof, Bennett Hotel and Sydney Junction Hotel confirm positive coronavirus case visits
- Coronavirus: Second Newcastle case confirmed as relative of St Pius X teenager
- Newcastle and Hunter coronavirus testing: full list of drive-through, walk-in and private clinics to test for COVID-19
- A billion vaccine doses on the way: Fauci
- Coronavirus latest: St Pius student caught bus, played for Jets in Sydney before positive test