SARS-CoV-2 variants: National definitions, classifications and public health actions

Last updated: May 14, 2021

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Preamble

The Public Health Agency of Canada, in collaboration with provincial and territorial public health authorities, established the Canadian SARS-CoV-2 Variant Surveillance Group (CSVSG) to monitor and assess the impact of variants of SARS-CoV-2 on viral transmissibility, disease severity, and efficacy of vaccines, therapeutics, and diagnostics. Drawing on published classifications and definitions by the World Health Organization (WHO)Footnote 1 and the US Centers for Disease Control and PreventionFootnote 2, the CSVSG has developed draft national definitions, classifications, and public health actions for SARS-CoV-2 Variants of Interest (VOI) and Variants of Concern (VOC).

The document also provides lists of designated VOI and VOC. These lists will be regularly reviewed and updated. Variant status may be escalated or de-escalated based on scientific evidence.

Variant of interest

Definition

A SARS-CoV-2 variant is a VOI if it

has a genome with mutations associated with changes in epidemiology, antigenicity, or virulence, or changes that potentially have a negative impact on available diagnostics, vaccines, therapeutics, or public health measures;

and

is known to cause community transmission/multiple COVID-19 cases/clusters in Canada or has been detected in multiple countries;

or

is otherwise assessed to be a VOI by WHO;

or

is otherwise assessed to be a VOI by the CSVSG.

Actions

If a variant is determined to be a VOI, actions may include the following:

Table 1. Variants of interest. Updated May 14, 2021
Name First detected Attributes
A.23.1 Rwanda

Predicted reduction in neutralization by some monoclonal antibody therapies

Predicted reduction in neutralization by polyclonal antibodies in convalescent sera

Notable mutations: S:P681R, S:Q613H

B.1.1.318 Switzerland

Predicted reduction in neutralization by some monoclonal antibody therapies

Predicted reduction in neutralization by polyclonal antibodies in convalescent sera

Notable mutations: S:E484K, S:P681H

B.1.427 USA

Early evidence of increased transmissibilityFootnote 3

Evidence of moderate neutralization by some monoclonal antibody therapiesFootnote 4

Notable mutations: S:L452R

B.1.429 USA

Early evidence of increased transmissibilityFootnote 3

Evidence of moderate neutralization by some monoclonal antibody therapiesFootnote 4

Notable mutations: S:L452R

B.1.525 Nigeria

Predicted reduction in neutralization by some monoclonal antibody therapies

Predicted reduction in neutralization by polyclonal antibodies in convalescent sera

Notable mutations: S:H69_V70del, S:Y144del, S:Q677H, S:E484K

B.1.526 USA

Predicted reduction in neutralization by some monoclonal antibody therapies

Predicted reduction in neutralization by polyclonal antibodies in convalescent sera

Notable mutations: S:E484K

B.1.616 France Early evidence of decreased ability to detect using standard testing methods
P.2 Brazil

Predicted reduction in neutralization by some monoclonal antibody therapies

Predicted reduction in neutralization by polyclonal antibodies in convalescent sera

Notable mutations: S:E484K

P.3 Philippines

Predicted increased transmissibility

Predicted reduction in neutralization by some monoclonal antibody therapies

Predicted reduction in neutralization by polyclonal antibodies in convalescent sera

Notable mutations: S:E484K, S:N501Y, S:P681H

Variant of concern

Definition

A SARS-CoV-2 variant is a VOC if, through a comparative assessment, it has been demonstrated to be associated with one or more of the following:

or

is otherwise assessed to be a VOC by WHO;

or

is otherwise assessed to be a VOC by the CSVSG.

Actions

If a variant is determined to be a VOC, actions may include the following:

Table 2. Variants of concern. Updated May 14, 2021
Name First detected  Attributes
B.1.1.7 UK

Evidence of increased transmissionFootnote 5

Evidence of increased severityFootnote 6, Footnote 7

Notable mutations: S:H69_V70del, S:Y144del, S:P681H, S:N501Y

B.1.351 South Africa

Evidence of increased transmissionFootnote 8

Evidence of impact on neutralization by polyclonal antibodiesFootnote 4

Evidence of reduced neutralization by convalescent sera and post-vaccination seraFootnote 9, Footnote 10, Footnote 11

Notable mutations: S:K417N, S:E484K, S:N501Y

B.1.617 India Evidence of increased transmissionFootnote 13
Evidence of impact on neutralization by polyclonal antibodiesFootnote 14
Evidence of reduced neutralization by convalescent sera and post-vaccination seraFootnote 14
Notable mutations: S:L452R, S:E484Q, S:G142D, S:P681R
N.B. Parent lineage designated VOC by WHO May 10, 2021. Evidence on sub-lineages (B.1.617.1, B.1.617.2, and B.1.617.3) is being reviewed and Canada designation may change.
P.1 Brazil/Japan

Evidence of impact on neutralization by polyclonal antibodiesFootnote 4

Evidence of reduced neutralization by convalescent sera and post-vaccination seraFootnote 12

Notable mutations: S:K417T, S:E484K, S:N501Y

References

Footnote 1

World Health Organization. COVID-19 Weekly Epidemiological Update. https://www.who.int/publications/m/item/covid-19-weekly-epidemiological-update (2021).

Return to footnote 1 referrer

Footnote 2

US Centres for Disease Control. SARS-CoV-2 Variant Classifications and Definitions. https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/variant-surveillance/variant-info.html (2021).

Return to footnote 2 referrer

Footnote 3

Deng, X. et al. Transmission, infectivity, and antibody neutralization of an emerging SARS-CoV-2 variant in California carrying a L452R spike protein mutation. medRxiv (2021) doi:10.1101/2021.03.07.21252647.

Return to footnote 3 referrer

Footnote 4

Fda, U. S. Fact sheet for health care providers emergency use authorization (Eua) of bamlanivimab and etesevimab. https://www.fda.gov/media/145802/download.

Return to footnote 4 referrer

Footnote 5

Davies, N. G. et al. Estimated transmissibility and impact of SARS-CoV-2 lineage B.1.1.7 in England. Science (2021) doi:10.1126/science.abg3055.

Return to footnote 5 referrer

Footnote 6

Davies, N. G. et al. Increased mortality in community-tested cases of SARS-CoV-2 lineage B.1.1.7. Nature (2021) doi:10.1038/s41586-021-03426-1.

Return to footnote 6 referrer

Footnote 7

Challen, R. et al. Risk of mortality in patients infected with SARS-CoV-2 variant of concern 202012/1: matched cohort study. BMJ372, (2021).

Return to footnote 7 referrer

Footnote 8

Estimates of severity and transmissibility of novel SARS-CoV-2 variant 501Y.V2 in South Africa. https://cmmid.github.io/topics/covid19/sa-novel-variant.html (2021).

Return to footnote 8 referrer

Footnote 9

Madhi, S. A. et al. Efficacy of the ChAdOx1 nCoV-19 Covid-19 Vaccine against the B.1.351 Variant. N. Engl. J. Med. (2021) doi:10.1056/NEJMoa2102214.

Return to footnote 9 referrer

Footnote 10

Novavax COVID-19 Vaccine Demonstrates 89.3% Efficacy in UK Phase 3 Trial. https://ir.novavax.com/news-releases/news-release-details/novavax-covid-19-vaccine-demonstrates-893-efficacy-uk-phase-3.

Return to footnote 10 referrer

Footnote 11

Johnson & Johnson COVID-19 Vaccine Authorized by U.S. FDA For Emergency Use. https://www.jnj.com/johnson-johnson-covid-19-vaccine-authorized-by-u-s-fda-for-emergency-usefirst-single-shot-vaccine-in-fight-against-global-pandemic.

Return to footnote 11 referrer

Footnote 12

Wang, P. et al. Increased Resistance of SARS-CoV-2 Variant P.1 to Antibody Neutralization. Cold Spring Harbor Laboratory 2021.03.01.433466 (2021) doi:10.1101/2021.03.01.433466.

Return to footnote 12 referrer

Footnote 13

Public Health England. (2020, December 23). Confirmed cases of COVID-19 variants identified in UK. GOV.UK. https://www.gov.uk/government/news/confirmed-cases-of-covid-19-variants-identified-in-uk

Return to footnote 13 referrer

Footnote 14

Hoffmann, M., Hofmann-Winkler, H., Krüger, N., Kempf, A., Nehlmeier, I., Graichen, L., Sidarovich, A., Moldenhauer, A.-S., Winkler, M. S., Schulz, S., Jäck, H.-M., Stankov, M. V., Behrens, G. M. N., & Pöhlmann, S. (2021). SARS-CoV-2 variant B.1.617 is resistant to Bamlanivimab and evades antibodies induced by infection and vaccination. In bioRxiv (p. 2021.05.04.442663). https://doi.org/10.1101/2021.05.04.442663

Return to footnote 14 referrer

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