Public health agencies like the World Health Organization (WHO) and the Centers for Disease Control and Prevention (CDC) monitor the genetic changes in viruses through genomic sequencing. When a new variant shows significant changes that pose potential threats, it is studied in-depth to understand its characteristics. A variant is classified as a VOC if it demonstrates increased transmissibility, more severe disease (e.g., increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, or reduced effectiveness of treatments or vaccines.
