The investigation suggested that coronaviruses use conformational masking and glycan shielding to limit recognition by the immune response of infected hosts. Similarly to SARS-CoV S and MERS-CoV, the investigation found that the SARS-CoV-2 S trimer exists in multiple, distinct conformational states resulting from SB opening at the trimer apex.  These structural changes are necessary for receptor engagement of these viruses and lead to initiation of fusogenic conformational changes.