Although limited by inherent constraints (notably the difficulty of co-crystallizing a viral antigen with a neutralizing antibody) and the fact that the analyzed structures are inherently static, which do not allow them to take into account the in vivo dynamic behavior of surface proteins (therefore an epitope identified on a crystal structure may not translate to an effective vaccine in vivo), this structure-based antigen design strategy is of particular value to build rapid responses to emerging new threats, as evidenced with the coronavirus disease 2019 pandemic. This evidence concerns the gene ERVW-1 and glycogen storage disease VI.