CCL2 and COVID-19: A novel gut microbiota-derived synbiotic formula known as SIM01, when administered as an adjuvant therapy in 25 COVID-19 patients, enhanced antibody formation against SARS-CoV-2 and reduced the inflammatory response, as measured by plasma interleukin (IL)-6, IL-1RA, monocyte chemoattractant protein (MCP-1), macrophage colony-stimulating factor (M-CSF) and TNF-α [79].