The World Health Organization declared the recently discovered B.1.1.529 strain of the COVID-19 virus to be a variant of concern on November 26 and renamed it Omicron. The classification puts Omicron into the most-troubling category of COVID-19 variants, along with the globally dominant Delta, plus its weaker rivals Alpha, Beta and Gamma. There are many studies that are underway to better characterize the variant. Follow CGTN for more details.