05/05/2021: Lab Advisory: SARS-CoV-2 Variants B.1.617, B.1.617.1, B.1.617.2, and B.1.617.3 Classified as Variants of Interest

CDC's Laboratory Outreach Communication System (LOCS)

Audience: Clinical Laboratory Professionals

Level: Laboratory Advisory:

On May 4, 2021, CDC, in coordination with the SARS-CoV-2 Interagency Group (SIG), classified SARS-CoV-2 variants B.1.617, B.1.617.1, B.1.617.2, and B.1.617.3 as variants of interest. B.1.617.3 was first detected in India in October 2020; B.1.617.1 and B.1.617.2 were first detected in India in December 2020, and B.1.617 was first detected in India in February 2021. Investigations are underway to further characterize additional B.1.617 lineage viruses and their potential impact on current tests, vaccines, and therapeutics.

SARS-CoV-2 variants can be categorized into the following three classes based on a Variant Classification scheme developed by a US government interagency group:

A variant of interest might require one or more appropriate public health actions, including

  • Enhanced sequence surveillance
  • Enhanced laboratory characterization
  • Epidemiological investigations to assess how easily the virus spreads to others, the severity of disease, the risk of reinfection, and whether currently authorized vaccines offer protection

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Online Resources:

If you have any questions, please contact us at LOCS@cdc.gov.

Thank you,

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

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

Centers for Disease Control and Prevention (CDC)

LOCS@cdc.gov

www.cdc.gov/csels/dls/locs

Page last reviewed: April 12, 2021