BackgroundCOVID-19 patients have severe lung injury. The USWD could play a supportive role in relieving lung injury and enhance clinical recovery.Methods and findingsThe design was a single-center, evaluator blinded; 2-arm parallel design superiority randomized controlled clinical trial. Moderate and severe coronavirus-2 (SARS-CoV-2) positive patients with acute respiratory syndrome, Fifty patients were randomized (USWD, 25; control, 25) between February 18/2020 and April 20/2020. There were male 22 (44.0%) and female 28 (56.0%) with mean (SD) age 53(10.69). Time to clinical recovery (USWD 36.84 vs control 43.56, P = 0.03) was significantly shortened with a between-group difference of 6.72 days. The median SIRS score at day 28 was 0 (0-1) in the USWD group, while 0 (0-2) in the control group (P = 0.011), and the seven-point scale at day 28 showed significant improvement in the USWD group (P = 0.003). While the rate of RNA negative conversion at day 7 (2/25 vs 7/25, p=0.054), day 14 (14/25 vs 18/25 p=0.239), day 21 (22/25 vs 18/25 p=0.279), and day 28 (25/25 vs 22/25 p=0.730) did not show statistical significance. Similarly, no significant differences were observed in the AI-assisted CT analysis. No treatment-associated adverse events or worsening of pulmonary fibrosis were found.ConclusionsAmong the 50 moderate and severe COVID-19 patients, the USWD as an adjunctive therapy to standard therapy could shorten the recovery course and enhance clinical improvement without aggravating pulmonary fibrosis. However, the study did not report statistical significance in the negative conversion rates of SARS-CoV-2 nucleic acid due to the small sample size and early termination, the findings of this study are limited.TRIAL REGISTRATIONChinese Clinical Trial Registry: ChiCTR2000029972, URL: http://www.chictr.org.cn/historyversionpuben.aspx?regno=ChiCTR2000029972