WHO’s working definitions and tracking system for SARS-CoV-2 variants of concern and variants of interest
WHO has updated its tracking system and working definitions for variants of SARS-CoV-2, the virus that causes COVID-19, to better correspond to the current global variant landscape, to independently evaluate Omicron sublineages in circulation, and classify new variants more clearly when required. SARS-CoV-2 continues to evolve. Since the beginning of the COVID-19 pandemic, multiple variants…