Table 1.

The characteristics of main variants of SARS-CoV-2 viruses.

Variants	Nextstrain clade	First identified	Spike protein mutations	Characteristics
Alpha	20I/501Y.V1	UK	ΔH69, ΔV70, Δ144, (E484K*), (S494P*), N501Y, A570D, D614G, P681H, T716I, S982A, D1118H (K1191N*)	Rapid transmissibility and higher infectivity
Beta	20H/501.V2	South Africa	D80A, D215G, Δ241, Δ242, Δ243, V367F, P384L, R408I, K417N, E484K, N501Y, D614G, A701V	Higher viral infectivity and immune escape
Gamma	20J/501Y.V3	Japan/Brazil	L18F, T20N, P26S, D138Y, R190S, K417T, E484K, N501Y, D614G, H655Y, T1027I, V1176F	Augment of viral transmissibility
Delta	21A/S:478K	India	T19R, (V70F*), T95I, G142D, E156-, F157-, R158G, (A222V*), (W258L*), (K417N*), L452R, T478K, D614G, P681R, D950N	Most contagious; higher viral replication; and leading to severe illness
Delta plus	NA	India	T95I, G142D, R158G, L452R, T478K, K417N	Increased transmissibility; high affinity with pulmonary epithelial cells; and immune evasion
Omicron	21K	South Africa	A67V, ΔH69, ΔV70, T95I, G142D, ΔV143, ΔY144, ΔY145, ΔN211, L212I, ins214EPE, G339D, S371L, S373P, S375F, K417N, N440K, G446S, S477N, T478K, E484A, Q493R, G496S, Q498R, N501Y, Y505H, T547K, D614G, H655Y, N679K, P681H, N764K, D796Y, Q954H, N969K, L981F, and N856K	Increased viral replication, infectivity and re-infection; increased transmissibility; immune escape; recombination with HCoV-229E viruses

UK, United Kingdom; Δ, deletion; ins, insertion; *, detected in some sequences but not all; NA, not available. The bold values show the shared mutation in all variants.