OBJECTIVES: To pool evidence on the safety and efficacy of MSCs in treating COVID-19 by observing MSC-related adverse effects as well as evaluating its effects in reducing inflammatory response and improving pulmonary function.

DATA SOURCES AND METHODS: Following literature search across six databases and one trial register, full-text retrieval, and screening against eligibility criteria, only eight studies were included for data extraction. All eight studies evaluated the use of umbilical cord-derived mesenchymal stromal/stem cell (UC-MSC), infused intravenously. Of these eight studies, six studies were included in meta-analysis on the incidence of mortality, adverse events (AEs), and serious adverse events (SAEs), and the levels of C-reactive protein (CRP) and interleukin (IL)-6. Meta-analysis on pulmonary function was not performed due to insufficient data.

RESULTS: MSC-treated group showed significantly lower risk of mortality than the control group (p = 0.03). No statistical significance was observed on the incidence of AEs (p = 0.78) and SAEs (p = 0.44), and the levels of CRP (p = 0.06) and IL-6 (p = 0.09).

CONCLUSION: MSCs were safe for use, with lower risk of mortality and no association with AEs. Regarding efficacy, descriptive analysis showed indications of improvement on the inflammatory reaction, lung clearance, and oxygenation status despite the lack of statistical significance in meta-analysis of CRP and IL-6. Nevertheless, more studies are needed for affirmation.