Recent research progress on subtypes of Omicron

Since the outbreak of Novel coronavirus pneumonia(COVID-19),Novel coronavirus has undergone evolution and variation in the process of transmission,and has formed many variant strains.There are five variants of concern,Alpha,Beta,Gamma,Delta and Omicron.In November 9,2021,South Africa firstly detected a variant strain(B.1.1.529)from a sample of cases.In November 26,the World Health Organization named it"Omicron variant strain",Currently,the Omicron variant strain has become the main epidemic variant strain in the world.Omicron variant strain consists of several subtypes,including BA.1,BA.2 and BA.3.The subtypes of Omicron variant strain have different mutation and infectivity.This article reviews the characteristics and immune escape mechanisms of each Omicron variant strain subtype.