Genetic variants of SARS-CoV-2 have been emerging and circulating around the world throughout the COVID-19 pandemic.
Viral mutations and variants in the United States are routinely monitored through sequence-based surveillance, laboratory studies, and epidemiological investigations.
A US government SARS-CoV-2 Interagency Group (SIG) interagency group developed a Variant Classification scheme that defines three classes of SARS-CoV-2 variants:
The B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617.2 (Delta), and P.1 (Gamma), variants circulating in the United States are classified as variants of concern.
To date, no variants of high consequence have been identified in the United States.
Laboratory studies suggest specific monoclonal antibody treatments may be less effective for treating cases of COVID-19 caused by variants with certain substitutions or combinations of substitutions in the spike protein.
L452R is present in B.1.526 (Iota), B.1.427 (Epsilon), and B.1.429 (Epsilon) lineages, as well as the B.1.617 (Kappa, Delta) lineages and sub-lineages.
E484K is present in B.1.525 (Eta), P.2 (Zeta), P.1 (Gamma), and B.1.351 (Beta), but only some strains of B.1.526 (Iota) and B.1.1.7 (Alpha).
The combination of K417N, E484K, and N501Y substitutions is present in B.1.351 (Beta).
The combination of K417T, E484K, and N501Y substitutions is present in P.1 (Gamma).
