PROS1 and viral infectious disease: A number of crystal and cryo-EM structures of the S proteins or RBDs of these CoVs or SARS-CoV-2 variants, as well as complexes with their respective receptors from human or other species, have been solved (Fig. 2) [2, 59, 68, 69], providing important information that can be used when designing effective counter measures to prevent and treat these viral infections.