What are the different variants of COVID-19? || What is Variant of Concern? || What is Variant of Interest? || Origin of different variants of COVID-19


The prime causative agent of COVID-19 is SARs-CoV-2, over time it has evolved into various genetically modified variants some of which are double mutant variants. 


Different mutants with greater transmissibility are reported from all over the globe, resulting in severe illness of the community. 


Till now total 194,608,040 confirmed cases and 4,170,155 confirmed deaths by COVID-19 are registered.




WHAT IS VARIANT OF CONCERN (VOC) ?


According to the CDC a variant for which there is evidence of an increase in transmissibility, more severe disease (e.g., increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures.

Let us dig deeper into the different variants and their origins.


SL. NO.

VARIANTS

FIRST DETECTED

INITIALLY DETECTED



1.

B.1.1.7 

(Alpha)

United States 

(December 2020 )

United Kingdom



2.

B.1.351 

(Beta)

United States

(end of January 2021)

South Africa 

(December 2020)



3.

P.1 

(Gamma)

United States 

(January 2021)

Identified in travelers from Brazil 

(early January)



4.

B.1.617.2 

(Delta)

United States 

(March 2021)

India 

(December 2020)


These variants seem to be more transmissible i.e. they spread more easily and quickly than other variants, which may lead to more cases of COVID-19. 



Selected Characteristics of SARS-CoV-2 Variants of Concern



B.1.1.7 (Pango lineage)


Name of the variant : 20I/501Y.V1

Spike Protein Substitutions: 69del, 70del, 144del, (E484K*), (S494P*), N501Y, A570D, D614G, P681H, T716I, S982A, D1118H (K1191N*)

WHO Label : Alpha

First Identified: United Kingdom


Characteristics :-

  1. Almost 50% increased transmission.
  2. Potential increased severity based on hospitalizations and case fatality rates.
  3. No impact on susceptibility to Emergency Use Authorization (EUA) monoclonal antibody treatments.
  4. Minimal impact on neutralization by convalescent and post-vaccination sera.



B.1.351 (Pango lineage)


Name of the variant : 20H/501.V2

Spike Protein Substitutions : D80A, D215G, 241del, 242del, 243del, K417N, E484K, N501Y, D614G, A701V

WHO Label : Beta

First Identified : South Africa


Characteristics :-

  1. Almost 50% increased transmission.
  2. Significantly reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment, but other EUA monoclonal antibody treatments are available .
  3. Reduced neutralization by convalescent and post-vaccination sera.



P.1 (Pango lineage)


Name of the variant : 20J/501Y.V3

Spike Protein Substitutions : L18F, T20N, P26S, D138Y, R190S, K417T, E484K, N501Y, D614G, H655Y, T1027I

WHO Label : Gamma

First Identified : Japan/Brazil


Characteristics :-

  1. Significantly reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment, but other EUA monoclonal antibody treatments are available.
  2. Reduced neutralization by convalescent and post-vaccination sera.




B.1.617.2 (Pango lineage)


Name of the variant : 21A/S:478K

Spike Protein Substitutions : T19R, (V70F*), T95I, G142D, E156-, F157-, R158G, (A222V*), (W258L*), (K417N*), L452R, T478K, D614G, P681R, D950N

WHO Label : Delta

First Identified : India


Characteristics :-

  1. Increased transmissibility
  2. Potential reduction in neutralization by some EUA monoclonal antibody treatments.
  3. Potential reduction in neutralization by post-vaccination sera.
  4. AY.1, AY.2 and AY.3 are currently aggregated with B.1.617.2. As data are available, CDC will continue to evaluate the independent classification of AY.1, AY.2, and AY.3.




WHAT IS VARIANT OF INTEREST (VOI) ?


According to the CDC, a variant with specific genetic markers that have been associated with changes to receptor binding, reduced neutralization by antibodies generated against previous infection or vaccination, reduced efficacy of treatments, potential diagnostic impact, or predicted increase in transmissibility or disease severity.


SL. NO.

VARIANTS

FIRST DETECTED



1.

B.1.427 

(Epsilon)

United States (California)

(June 29, 2021)



2.

B.1.429

(Epsilon)

United States (California)

(June 29, 2021)



3.

B.1.525

(Eta)

United Kingdom / Nigeria

(December 2020)



4.

B.1.526

(Iota)

United States (New York) 

(November 2020)



5.

B.1.617.1

(Kappa)

India

(December 2020)



6.

B.1.617.3

(Kappa sublineage)

India 

(October 2020)



Selected Characteristics of SARS-CoV-2 Variants of Interest



B.1.427 


Name of the variant : 20C/S:452R

Spike Protein Substitutions: L452R, D614G

WHO Label : Epsilon

First Identified : United States-(California)


Characteristics :-

  1. Almost 20% increased transmission
  2. Modest decrease in susceptibility to the combination of bamlanivimab and etesevimab; however, the clinical implications of this decrease are not known. Alternative monoclonal antibody treatments are available.
  3. Reduced neutralization by convalescent and post-vaccination sera.
  4. Deescalated from a VOC on June 29, 2021, due to the significant decrease in the proportion of B.1.427 lineage viruses circulating nationally and available data indicating that vaccines and treatments are effective against this variant.



B.1.429 (Pango lineage)


Name of the variant : 20C/S:452R

Spike Protein Substitutions : S13I, W152C, L452R, D614G

WHO Label : Epsilon

First Identified : United States-(California)


Characteristics :-

  1. Almost 20% increased transmission
  2. Reduced susceptibility to the combination of bamlanivimab and etesevimab; however, the clinical implications of this decrease are not known. Alternative monoclonal antibody treatments are available.
  3. Reduced neutralization by convalescent and post-vaccination sera.
  4. Deescalated from a VOC on June 29, 2021, due to the significant decrease in the proportion of B.1.429 lineage viruses circulating nationally and available data indicating that vaccines and treatments are effective against this variant.



B.1.525 (Pango lineage)


Name of the variant : 20A/S:484K

Spike Protein Substitutions : A67V, 69del, 70del, 144del, E484K, D614G, Q677H, F888L

WHO Label : Eta

First Identified : United Kingdom/Nigeria – December 2020


Characteristics :-

  1. Potential reduction in neutralization by some Emergency Use Authorization (EUA) monoclonal antibody treatments.
  2. Potential reduction in neutralization by convalescent and post-vaccination sera.



B.1.526 (Pango lineage)


Name of the variant : 20C/S:484K

Spike Protein Substitutions : L5F, (D80G*), T95I, (Y144-*), (F157S*), D253G, (L452R*), (S477N*), E484K, D614G, A701V, (T859N*), (D950H*), (Q957R*)

WHO Label : Iota

First Identified : United States (New York) – November 2020


Characteristics :-

  1. Reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment; however, the clinical implications of this are not known. Alternative monoclonal antibody treatments are available.
  2. Reduced neutralization by convalescent and post-vaccination sera. B.1.526.1 sub-lineage has been consolidated with this parent lineage.


B.1.617.1 (Pango lineage)


Name of the variant : 20A/S:154K

Spike Protein Substitutions: (T95I), G142D, E154K, L452R, E484Q, D614G, P681R, Q1071H

WHO Label : Kappa

First Identified: India – December 2020


Characteristics :-

  1. Potential reduction in neutralization by some EUA monoclonal antibody treatments.
  2. Potential reduction in neutralization by post-vaccination sera.



B.1.617.3 (Pango lineage)


Name of the variant : 20A

Spike Protein Substitutions: T19R, G142D, L452R, E484Q, D614G, P681R, D950N

First Identified: India – October 2020


Characteristics :-

  1. Potential reduction in neutralization by some EUA monoclonal antibody treatments.
  2. Potential reduction in neutralization by post-vaccination sera.




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