More recently, a growing number of clinical investigations of cell-based therapies, primarily involving mesenchymal stem (stromal) cells (MSCs) but also utilising MSC-derived conditioned media or extracellular vesicles and several other cell types, have been initiated in China for COVID-19 respiratory disease. As these encompass a wide range of approaches and targeted patient groups, it is imperative to better understand the rationale of the studies and the potential mechanisms of MSC actions towards respiratory viral infections. Recent pre-clinical data in models of respiratory virus infections and relevant related clinical studies of MSC administration in patients with ARDS can contribute to better definition of the patient population for whom potential MSC-based cell therapy approaches might be considered.