Human C5a receptor 1 (C5aR1), which binds to the pro-inflammatory mediator C5a, is primarily expressed on the surfaces of various immune cells, such as neutrophils, eosinophils, and dendritic cells.281,282 Overactivation of the C5aR1-C5a axis will cause uncontrolled inflammation;283 thus, C5aR1 antagonists are ideal candidates for treating various inflammatory conditions, including sepsis COVID-19, etc.284–286. This evidence concerns the gene C5AR1 and COVID-19.