PROS1 and COVID-19: Indeed, all the first COVID-19 vaccines use a full-length S protein as a vaccinating antigen and generate non-precision immunity mainly directed to the immunodominant although genetically variable RBD epitopes (Bestle et al., 2020; Piccoli et al., 2020; Chen et al., 2021), which explains their decreased efficiency with SARS-CoV-2 genetic variants.