Interestingly, Qin et al. [19] demonstrated that severe COVID-19 is associated with increased α2,6-sialylation compared to both healthy individuals (p < 0.0001) and patients with mild COVID-19 (p < 0.01), but this study examined the entire plasma glycoproteome, particularly complement proteins, as well as lung tissue samples. This evidence concerns the gene VTN and COVID-19.