Table 2.

The identification, emergency, changes, and neutralizing antibody activity of SARS-CoV-2 variants, called variants of concern (VOCs), during 2020~2022.

Identification		Emergency		Changes Relative to Previously Circulating Variants		Neutralizing Antibody Activity		Date of Designation	Reference
WHO label	PANGO lineage	First outbreak country	Current circulation	Transmissibility	Mortality	From infection	From vaccination		[42,43,44]
Omicron	B.1.1.529	South Africa	Yes	Possibly increased	−63% (69–74%) related to Delta	Increased reinfection rate	Efficacy reduction against symptomatic disease, unknown for severe disease	VUM: 24 November 2021 VOC: 26 November 2021	[42,43,45,46,47,48,49,50]
Delta	B.1.617.2	India	No	+97% (76–117%)	+137% (50–230%)	Reinfections have smaller occurrence rate than vaccinated infections	Efficacy reduction for non-severe diseases	VOI: 4 April 2021 VOC: 11 May 2021 Previous VOC: 7 June 2022	[42,43,45,46,47,48,49,50]
Gamma	P.1 (B.1.1.28.1)	Brazil	No	+38% (29–48%)	+59% (44–74%)	Reduced	Retained by many	VOC: 11 January 2021 Previous VOC: 9 March 2022	[42,43,45,46,47,48,49,50]
Alpha	B.1.1.7	UK	No	+29% (24–33%)	+50% (50% CrI, 20–90%)	Minimal reduction	Minimal reduction	VOC: 18 December 2020 Previous VOC: 9 March 2022	[42,43,45,46,47,48,49,50]
Beta	B.1.351	South Africa	No	+25% (20–30%)	Possibly increased	Reduced	Efficacy reduction against symptomatic disease, retained against severe disease	VOC: 18 December 2020 Previous VOC: 9 March 2022	[42,43,45,46,47,48,49,50]

Abbreviation: variant under monitoring (VUM); variant of interest (VOI); variant of concern (VOC); World Health Organization (WHO); the Phylogenetic Assignment of Named Global Outbreak Lineages (PANGOLIN). The reported confidence or credible interval (Crl) has a low probability, so the estimated value can only be understood as possible, not certain, or likely.