Swiss School Study of 87 Infections: Shared Classroom Risk Ratio 3.17 vs 1.16 for Close Proximity
A six-week longitudinal study in a Swiss secondary school published in Nature Communications found that respiratory virus transmission was driven more by prolonged exposure in shared, poorly ventilated classrooms than by close contact alone. The study followed 67 students aged 14 to 15 during winter 2023/24.
Researchers detected 87 infections in saliva samples, measured time in close proximity within 1.5 metres using wearable sensors, and monitored air quality via CO2 sensors. Students spent 21.2 minutes per day in close proximity and 5.3 hours in shared classrooms, during which air quality was suboptimal for 1.9 hours.
Using pairwise survival models, time in shared classrooms predicted within-class transmission with a rate ratio of 3.17 (95% CI 1.96 to 5.17), suboptimal air quality with a rate ratio of 1.90 (1.23 to 2.94), while close proximity was modestly associated at 1.16 per doubling of daily time (1.01 to 1.33).
Source: Nature Communications
Published by GSM · USA (original Chinese edition)
Photo: 一间瑞士学校的教室。照片：Marketing EHL Hotelfachschule Passugg，CC BY-SA 4.0，经 Wikimedia Commons / A classroom in Switzerland. Photo: Marketing EHL Hotelfachschule Passugg, CC BY-SA 4.0, via Wikimedia Commons
