PROS1 and COVID-19: Considering the number and complexity of receptor/ligand systems whose interactions depend on the glycan moieties and their relevance in anti-pathogen immunity [11,15,16], the biological significance of glycan moieties decorating the S protein of SARS-CoV-2 is an attractive topic for research aimed at ascertaining the role of N-glycans in protection from, and/or pathology of, COVID-19.