Bo Yao1, Jin-Yan Xing2. 1. The Department of Critical Care Medicine, The Affiliated Hospital of Qingdao University, Wutaishan Road 1677, Qingdao City 266000, China; Systems Biology and Medicine Center, The Affiliated Hospital of Qingdao University, Wutaishan Road 1677, Qingdao City 266000, China. Electronic address: icuyaobo@126.com. 2. The Department of Critical Care Medicine, The Affiliated Hospital of Qingdao University, Wutaishan Road 1677, Qingdao City 266000, China. Electronic address: icuxingjinyan@126.com.
To the Editor,In late December 2019, the 2019 novel coronavirus (COVID 2019) began to spread throughout China. Some medical workers (including one of the authors) were recruited as frontline medical workers (FMW) fighting COVID 2019. During this period, Dr Yao's sleep quality became very poor. Sleep deprivation has detrimental effects on immune response and may lead to increased susceptibility to infections [1]. Previous studies showed 38%–78.4% FMW had sleep disturbance during the outbreak of COVID 2019 [2,3]. However, these studies were all cross-sectional. Therefore, we performed a prospective follow-up study focusing on changes in sleep quality in FMW. The sleep quality of 51 FMW in our hospital was evaluated by Sleep State Self-Rating Scale (SRSS) [4] during four periods (ie, in the period of daily life [pre COVID 19], the days fighting against COVID 19 as a FMW, 14-day self-isolation, and the seventh day after finishing self-isolation).Our study found that SRSS scores differentiated these four periods [21 (17–24) vs. 25 (20–31) vs. 20 (17–27) vs. 20 (17–23), P = 0.036]. In the days fighting against COVID 19, SRSS scores were higher than daily life and 47.1% of FMW sleep quality worsened. During the periods of self-isolation and the seventh day after finishing self-isolation, SRSS scores recovered to daily life level. However, dispersion of SRSS scores were much wider than daily life. While in the self-isolation period, 52.6% of FMW sleep quality improved, yet, 27.7% of individuals sleep quality worsened. Furthermore, on the seventh day after finishing self-isolation, 27.1% of FMW still did not recover to daily sleep quality levels. Moreover, FMW who were married or had children found recovery to pre-COVID 19 daily sleep levels easier than single workers (married/not married 26/9 vs. 5/8, P = 0.039; having child/having no child 24/11 vs. 3/10, P = 0.005). In conclusion, attention should be paid to our findings which showed that FMW sleep quality decreased during the days fighting against COVID 19 but in some cases also during and after isolation.