Researchers from the National Centre for Immunisation Research and Surveillance (NCIRS) and the University of Sydney released their preliminary findings from this work from January to April 2020.

The Lancet publication today contains detailed analysis on COVID-19 spread in 25 educational settings (15 schools and 10 childcare settings) in Term 1. Additional data from Term 2 and 3 are also available today.

Lead author Professor Kristine Macartney said the study showed transmission rates in NSW schools and early childhood education and care (ECEC) services were minimal, particularly between children and from children to adults.

"This is the first comprehensive population-based assessment of coronavirus transmission in educational settings worldwide," Professor Macartney said.

"COVID-19 transmission in schools appears to be considerably less than that seen for other respiratory viruses, such as influenza.

"This supports the previous findings that COVID-19 transmission in educational settings can be kept low and manageable in the context of an effective pandemic response that includes contact tracing and quarantine, and temporary school closures for cleaning if someone is found to be infected.

"It is also consistent with other data that show lower rates, and generally milder disease, in children than in adults.

"However, it is important to view these findings in the context of the NSW outbreak. Higher rates of transmission may occur in areas with higher levels of virus transmission in the community or with less rigorous public health and community response."

In Term 1 and 2 there have been 33 initial cases of COVID-19 confirmed at 31 of NSW's 7700 schools and ECEC services, with 25 sites in Term 1 and six during Term 2 affected.

In Term 1 and 2, a total of 16 students and 17 adult staff were the first cases who tested positive for the virus.

Out of 1333 close contacts in primary and high schools, just five (0.4%) possible secondary infections were recorded across Terms 1 and 2: one primary student, two high school students, one primary teacher and one high school teacher.

Initial cases were also seen in 11 ECEC services across Term 1 and 2, with 13 possible secondary infections recorded out of 636 close contacts.

All 13 secondary cases (7 children and 6 staff) were linked to an outbreak at a single ECEC service early in Term 1 that started initially in staff members. No secondary cases were identified in the other 10 ECEC services.

This observational study is continuing in Term 3 in NSW (July -- September). Data for Term 3 is preliminary but as at 3 August, there have been 11 cases (3 staff members and 8 students) with two secondary infections being recorded in one primary school and one ECEC service.

"We know anyone of any age can be infected and potentially spread the virus," Prof Macartney said.

"But understanding how the virus spreads in our context will assist modellers, policymakers, healthcare providers, and the public to understand the risk of COVID-19 in educational settings and help in decision making around school closures and re-openings."