The term variant of concern (VOC) for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, which causes COVID-19) is a category used for variants of the virus where mutations in their spike protein receptor binding domain (RBD) substantially increase binding affinity (e.g., N501Y) in RBD-hACE2 complex (genetic data), while also being linked to rapid spread in human populations (epidemiological data).[1]

懸念される変異株（Variants of Concern : VOC）