CCL2 and COVID-19: A previous study has demonstrated the use of one-step real-time RT-qPCR for detection of chemokines mRNA in nasopharyngeal swabs, and the predictive value of C–C motif chemokine Ligand 2/Monocyte chemoattractant protein-1 (CCL2/MCP-1) within 5 days of symptom onset in determining the severity of COVID-19 [11].