Kingspark School shut last Wednesday after 17 teachers, two pupils, and three contacts tested positive for coronavirus.
Teachers and pupils are now self-isolating for 14 days.
Contact tracers had identified links to two other schools.
Dr Ellie Hothersall, a consultant in public health medicine with NHS Tayside, told The Guardian, that a detailed contact tracing programme is tackling the spread.
“Since the identification of positive cases at Kingspark, a detailed contact-tracing programme has been under way and these linked cases are being identified because of those concerted efforts of test and protect", he said.
“We must do everything we can to protect all of our communities against Covid-19 and that is why we have issued the guidance to self-isolate. By taking this action we are containing any further spread of infection.
“We know that this may cause anxiety to some parents and children but we must do everything we can to ensure we keep people safe.”
It comes as a total of 66 people in Scotland tested positive for Covid-19 in the past 24 hours, Nicola Sturgeon has announced.
The First Minister told the Scottish Government’s regular coronavirus briefing the total number of people who have tested positive is now 19,877.
