To date, no specific drugs have been shown to be effective in alleviating lymphopenia in patients with COVID-19. Sleep is a physiological and behavioral process required for survival and plays an important role in metabolism and immune system homeostasis (Besedovsky et al., 2019, Haspel et al., 2020, Mukherjee et al., 2015); indeed, sleep and immunity are bidirectionally linked (Besedovsky et al., 2019). Sleep disturbance impairs innate and adaptive immune responses and activates inflammation, with an increase in circulating inflammatory cytokines due to disruption of the circadian rhythms (Haack et al., 2007, Irwin, 2015, Vgontzas et al., 2004). Short-term sleep deprivation is associated with compromised natural killer cell activity in the blood (Fondell et al., 2011). Disruption of the circadian rhythm of sleep, shorter sleep duration, or poor quality of sleep could increase susceptibility to upper respiratory infections (Cohen et al., 2009, Loef et al., 2019, Patel et al., 2012, Prather et al., 2015). In fact, septic patients with frequently disrupted sleep have higher mortality rates (Huang et al., 2014). Sleep impairment occurs frequent in patients with COVID-19 (Liguori et al., 2020), which may be due to isolated environment without family member’ companion, physical discomfort caused by the illness, or psychological factor (fear, anxiety, helplessness and/or depression, etc.) (Guo et al., 2020). However, there are currently no reports of the effects of sleep quality during hospitalization on immune function recovery and prognosis in patients with COVID-19. In tour study, we aimed to describe the effects of self-reported sleep quality on recovery from lymphopenia, deterioration based on an increased NLR, and clinical outcomes in hospitalized patients with COVID-19.