09/22/2021: Lab Advisory: CDC Updates SARS-CoV-2 Variant Classifications

CDC's Laboratory Outreach Communication System (LOCS)

Audience: Clinical Laboratory Professionals

Level: Laboratory Advisory

On September 21, 2021, the U.S. Government SARS-CoV-2 Interagency Group (SIG) added a new variant classification designated Variants Being Monitored (VBM).

VBM may include variants previously designated as a Variant of Interest (VOI) or Variant of Concern (VOC) that are no longer detected or are circulating at very low levels in the United States. VBM may also include variants designated by other organizational committees (e.g., WHO Technical Advisory Group for SARS-CoV-2 Virus Evolution) that have substitutions of concern but that have not been deemed a public health threat within the United States by the SIG at this time.

In general, to be classified as a VBM, there are laboratory data indicating that antibodies elicited during previous infection or vaccination have reduced neutralization activity against the variant or the variant has reduced susceptibility to FDA authorized monoclonal antibody treatments. VBM may also include variants that have been associated with more severe disease or increased transmission.

As of September 21, 2021, the following variants are classified as VBM:

  • Alpha (B.1.1.7, Q.1-Q.8)
  • Beta (B.1.351, B.1.351.2, B.1.351.3)
  • Gamma (P.1, P.1.1, P.1.2)
  • Epsilon (B.1.427, B.1.429)
  • Eta (B.1.525)
  • Iota (B.1.526)
  • Kappa (B.1.617.1)
  • B.1.617.3
  • Mu (B.1.621, B.1.621.1)
  • Zeta (P.2)

Due to their very low prevalence in the United States, these variants do not pose a significant and imminent risk to public health in the United States. CDC will continue to monitor these variants closely to identify changes in their proportions. If a VBM warrants more concern, the classification will be changed based on the SIG assessment of the attributes of the variant and the risk to public health in the United States.

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Thank you,

The Laboratory Outreach Communication System

Laboratory Outreach Communication System (LOCS) | Division of Laboratory Systems (DLS)

Center for Surveillance, Epidemiology, and Laboratory Services (CSELS)

Centers for Disease Control and Prevention (CDC)