2. Named by WHO. According to the announcement issued by WHO on the afternoon of 26th, the mutant B. 1. 1.529 appeared in South Africa was identified as the highest-level COVID-19 mutant and named Omicron.
3. According to the previous naming, the name of COVID-19 mutant is novel after each mutation, so this time the Omicron mutant also followed the previous naming experience. COVID-19 mutant viruses are all named after Greek letters, and Omicron is named after "Omi-cron" (the 5th Greek letter ο/kloc-0).