ABSTRACT
Background: School closure is one of the main global health policies performed worldwide during the coronavir us di sease 2019 (COVID-19) outbreak. Despite all of the advantages, there may be some risks for children who are quarantined. This study aimed to objectively measure and compares the sleep patterns of Hong Kong school students before and during the COVID-19 outbreak. Methods: Baseline assessment was performed before the first wave of the COVID-19 outbreak in Hong Kong. The sleep pattern was recorded by a physical activity monitor (Actigraph wGT3X-BT, Pensacola, Florida, USA). The follow-up assessment was conducted in early 2020. Findings: In total, 718 students were collected in the baseline . Sub sequently 1 40 students joined t he reassessment between March and April 2020. Analysis of sleep timing shows that 98.0% primary students, 78.0% secondary students and 79.9% primary school students and 58.8% secondary school students go to bed before midnight before and after the outbreak, respectively (p<0.001). Mean sleep duration (hours) was 6.81 (0.62) and 8.09 (0.07) at baseline and during the outbreak, respectively. The differences in the mean sleep features for total sleep time, sleep fragmentation index and sleep fragmentation were 0.92 (1.64), 1.64 (6.95) and 2.49 (9.18), respectively. The overall sleep quality was poorer as evidenced by delays in bedtime and wake up time, increased duration in bed, longer sleep latency, increases in the movement and fragmentation indices. Conclusion: This exceptional longitudinal study reported objective data on the change in sleep patterns before and during the COVID-19 outbreak with school closures.