Three students from a Western Sydney school have tested positive for COVID-19, forcing the school to close while deep cleaning and contact tracing are conducted.
NSW Health said all 136 Year 10 students at St Paul's Catholic College in Greystanes are considered close contacts and must self-isolate for 14 days.
The cases are among 13 new infections recorded in NSW yesterday, but it is unknown how the first of the three students became infected.
This follows a string of other school closures in recent days, including Ryde Secondary College and St Gertrude's Primary School, where a staff member and a student tested positive.
Other NSW schools to close in recent days include Homebush Public School, Girraween Public School and Double Bay Public School.
Earlier in the month, positive cases led to the closure of Tangara School for Girls, Bonnyrigg Heights Primary Pius X High School in Adamstown NSW, St Vincent College in Potts Point, Our Lady of Mercy College in Parramatta, Parramatta Public School and Bateman's Bay Public School.
University of Melbourne epidemiologist Tony Blakely recently told the ABC that the presence of cases without a known source was “a good signal” actual case numbers could be up to 10 times higher than the official figures.
“If they've got an average of 20 cases per day in the last week, that means that at any one point in time, there's about 200 other cases out there that we don't know about,” he said.
“Basically, 10 times the daily count”.