SARS-COV-2 VARIANTS

UPDATE 12/18/2023: The Rocky Mountain COVID Data surveillance dashboard, variants page, blog, and other parts of the website were updated for the last time on Monday, December 18, 2023. Please see our final blog post for information on other resources to help you stay knowledgeable.

The Rocky Mountain COVID Data project strives to provide relevant and easily understandable information to empower state, local, and tribal health leaders across the Rocky Mountain West in public health planning and response. As part of this goal, we have compiled relevant details on both current and historically circulating SARS-CoV-2 variants circulating in the Rocky Mountain West as well as other variants of concern or variants being monitored.

For the latest updates and news, you can also check out our blog page below.

Variants in the Rocky Mountain West

Below are the main variants that circulated in the Rocky Mountain West. For each variant, we provide information on the number and type of mutations (specifically, whether or not mutations are believed to impact therapeutics), estimated transmissibility, and estimated severity. Information on mutations was obtained from the NCBI SARS-CoV-2 Variants Overview database at NIH.* Information on estimated transmissibility and severity was obtained from the scientific literature. Variants are listed from newest to oldest.

*Note that the number and type of mutations given are with respect to the given parent lineage.

  • Parent Lineage: BA.2.86

    Mutations: 1 therapeutic + 3 nontherapeutic

    First Identified in the US: September 2023

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1. Assumed to be roughly the same as BA.4, BA.5, BQ.1, BQ.1.1, XBB, XBB.1.5, EG.5, BA.2.86, and HV.1.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1, BA.2, BA.2.12.1, BA.4, BA.5, BQ.1, BQ.1.1, XBB, XBB.1.5, EG.5, BA.2.86, and HV.1.

  • Parent Lineage: EG.5

    Mutations: 1 therapeutic + 3 nontherapeutic

    First Identified in the US: August 2023

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1. Assumed to be roughly the same as BA.4, BA.5, BQ.1, BQ.1.1, XBB, XBB.1.5, EG.5, and BA.2.86.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1, BA.2, BA.2.12.1, BA.4, BA.5, BQ.1, BQ.1.1, XBB, XBB.1.5, and EG.5, and BA.2.86.

  • Parent Lineage: BA.2

    Mutations: 34 total

    First Identified in the US: August 2023

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1. Assumed to be roughly the same as BA.4, BA.5, BQ.1, BQ.1.1, XBB, XBB.1.5, and EG.5.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1, BA.2, BA.2.12.1, BA.4, BA.5, BQ.1, BQ.1.1, XBB, XBB.1.5, and EG.5.

  • Parent Lineage: XBB.1.9.2

    Mutations: 1 therapeutic

    First Identified in the US: May 2023

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1. Assumed to be roughly the same as BA.4, BA.5, BQ.1, BQ.1.1, XBB, and XBB.1.5.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1, BA.2, BA.2.12.1, BA.4, BA.5, BQ.1, BQ.1.1, XBB, and XBB.1.5.

  • Parent Lineage: BA.2

    Mutations: 2 therapeutic + 4 nontherapeutic

    First Identified in the US: October 2022

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1. Assumed to be roughly the same as BA.4, BA.5, BQ.1, BQ.1.1, and XBB.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1, BA.2, BA.2.12.1, BA.4, BA.5, BQ.1, BQ.1.1, and XBB.

  • Parent Lineage: BA.2

    Mutations: 1 therapeutic + 3 nontherapeutic

    First Identified in the US: October 2022

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1. Assumed to be roughly the same as BA.4, BA.5, BQ.1, and BQ.1.1.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1, BA.2, BA.2.12.1, BA.4, BA.5, BQ.1, and BQ.1.1.

  • Parent Lineage: BA.5

    Mutations: 3 therapeutic + 3 nontherapeutic

    First Identified in the US: September 2022

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1. Assumed to be roughly the same as BA.4, BA.5, and BQ.1

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to roughly the same as BA.1, BA.2, BA.2.12.1, BA.4, BA.5, and BQ.1.

  • Parent Lineage: BA.5

    Mutations: 2 therapeutic + 2 nontherapeutic

    First Identified in the US: September 2022

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1. Assumed to be roughly the same as BA.4 and BA.5.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to roughly the same as BA.1, BA.2, BA.2.12.1, BA.4, and BA.5.

  • Parent Lineage: BA.2

    Mutations: 1 therapeutic + 1 nontherapeutic

    First Identified in the US: April 2022

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1. Assumed to be roughly the same as BA.4.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1, BA.2, BA.2.12.1, and BA.4.

  • Parent Lineage: BA.2

    Mutations: 1 therapeutic + 3 nontherapeutic

    First Identified in the US: April 2022

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1, BA.2, and BA.2.12.1.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1, BA.2, and BA.2.12.1.

  • Parent Lineage: BA.2

    Mutations: 1 therapeutic + 5 nontherapeutic

    First Identified in the US: April 2022

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1. Assumed to be roughly the same as BA.2.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1 and BA.2.

  • Parent Lineage: BA.1

    Mutations: 3 nontherapeutic

    First Identified in the US: January 2022

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype. Assumed to be slightly higher than BA.1.

    Estimated Severity: Assumed to be lower than Alpha, Delta, and Wildtype. Assumed to be roughly the same as BA.1.

  • Parent Lineage: Wildtype

    Mutations: 4 nontherapeutic

    First Identified in the US: December 2021

    Estimated Transmissibility: Assumed to be higher than Delta, Alpha, and Wildtype.

    Estimated Severity: Assumed to be lower than Delta, Alpha, and Wildtype.

  • Parent Lineage: Wildtype

    Mutations: 15 nontherapeutic

    First Identified in the US: March 2021

    Estimated Transmissibility: Assumed to be higher than Alpha and Wildtype.

    Estimated Severity: Assumed to be higher than Alpha and Wildtype.

  • Parent Lineage: Wildtype

    Mutations: 1 therapeutic + 9 nontherapeutic

    First Identified in the US: December 2020

    Estimated Transmissibility: Assumed to be higher than Wildtype.

    Estimated Severity: Assumed to be higher than Wildtype.

  • Parent Lineage: Original

    Mutations: N/A

    First Identified in the US: January 2020

    Estimated Transmissibility: Baseline

    Estimated Severity: Baseline

Variant Proportions Weekly from the CDC

CDC COVID Data Tracker Variant Lineages

The CDC tracks and visualizes the different strains of SARS-CoV-2 dating back to its ancestral strain. The diagram, below, from CDC, shows the latest variants and their origins.

Other Variants of Concern

We strive to keep our audiences informed of SARS-CoV-2, both past and present, that have the ability to grow significantly in the Rocky Mountain West region. Many other variants have been detected and monitored but do not have a significant presence in the region at this time. For more on other variants of concern, please see the resource list provided.

CDC SARS-CoV-2 Variant Classifications and Definitions 

CDC SARS-CoV-2 Variant Proportions Dataset

CDC Variants & Genomic Surveillance 

COVID-19 Variant Sentinel Surveillance Colorado 

covSPECTRUM 

SARS-CoV-2 Lineage Comparison 

PANGO CoV Lineages 

Variants in the EU/EEA 

WHO Tracking SARS-CoV-2 Variants