MMP9 and susceptibility to pneumonia measurement: Studies have demonstrated the immunological efficacy of components of Chinese medicine in treating COVID-19: for example, components in Ephedra sinica can alleviate pneumonia symptoms by reducing the production of IL-6, IL-8, TNF-α, and MMP-9 (179), and quinoline-2-carboxylic acids in Ephedra sinica can disrupt the interaction between ACE2 and SARS-CoV-2 RBD (181).