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Transmission of COVID-19 in NSW educational settings in Term 3 and Term 4 2021

Spread of COVID-19 in New South Wales (NSW) schools did not dramatically increase despite the emergence of the Omicron variant and sharp rise in case notifications and school exposure events in late 2021.

In Term 4 2021, the majority of students returned to the classroom. There were 985 exposure events involving 1,206 individual ‘index’ (first) cases across the 3,107 NSW schools; 81 per cent of the index cases were students and 19 per cent staff members. The overwhelming majority of these index cases were unvaccinated, according to the latest report from the National Centre for Immunisation Research and Surveillance (NCIRS).

The COVID-19 in schools and early childhood education and care services in NSW, Australia term 3 and term 4 2021 reports provide the latest data from an ongoing study by NCIRS and the University of Sydney, in collaboration with NSW Health and NSW Department of Education, which has tracked transmission of COVID-19 in educational settings since March 2020.

“61 per cent of school exposure events in Term 4 were in primary schools, consistent with the very low numbers of 5–11 year olds vaccinated prior to the January 2022 rollout of the vaccination program for this age group,” Professor Kristine Macartney, NCIRS Director, said.

“School staff also represented a greater proportion of cases following the introduction of Omicron from late November, emphasising the need for booster vaccination in this group.”

From 18 October to 17 December 2021, there were 23,899 locally acquired COVID-19 cases in NSW, of which 33 per cent were in people aged 19 years and under.

“Even with the high numbers of exposure events in Term 4 we did not see a dramatic increase in onward transmission in schools,” said Dr Archana Koirala, a paediatric infectious disease specialist and Clinical Associate Lecturer at the University of Sydney who is leading the study.

“In high schools onward transmission was lower, likely a result of strong COVID-19 vaccine uptake by staff and children aged 12 years and over, as well as other prevention strategies.”

Our findings confirm that vaccination of students and teachers as well as other mitigation measures in schools and the wider community can keep transmission low in educational settings, enabling schools to deliver the face-to-face learning that children need,” she added.

Resumption of full face-to-face learning in Term 4 increased the number of exposure events, from a median of 22 schools per week in Term 3 with a median 10 per cent attendance to 87 schools per week with a median 89 per cent attendance. Around half of all Term 4 school COVID-19 exposures occurred in the fortnight of 4–17 December 2021.

However, the secondary attack rate - the proportion of close contacts in educational settings infected after being exposed, remained low in Term 4 at 2.9 per cent overall, and lowest in high schools at 1.0 per cent. There was a modest increase in transmission in the last part of Term 4 in schools where the Omicron variant was introduced (3.7%) compared with schools with the Delta variant (secondary attack rate 2.4%).

Read the full reports here


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