Variants of the Virus that Causes COVID-19
Genetic variations of viruses such as the one that causes COVID-19 are not uncommon and many other variants of the SARS-CoV-2 virus have been previously observed around the world this year. Both new variants include mutations (i.e., changes to the genetic material in the virus) on the “spike” protein, which may result in the virus becoming more infectious and spreading more easily between people. These variants have been termed variants of concern (VOCs) and have been associated with evidence of increased transmissibility, severity, and/or possible immune evasion with potential implications for reinfection and vaccine effectiveness.
Multiple variants of the virus that causes COVID-19 are circulating globally. To date, three SARS-CoV-2 variants of public health importance have been identified:
Multiple variants of the virus that causes COVID-19 are circulating globally:
- The United Kingdom (UK) identified a variant called B.1.1.7 (501Y.V1, VOC 202012/01), also referred to as Alpha with a large number of mutations in the fall of 2020. This variant spreads more easily and quickly than other variants.
- The variant B.1.351 (Beta) emerged in South Africa. Originally detected in early October 2020, B.1.351(501Y.V2) shares some mutations with B.1.1.7.
- In Brazil, a variant called Gamma (P.1, previously P.1.1.28) emerged in January 2021. This variant was first identified in travelers from Brazil, who were tested during routine screening at an airport in Japan. This variant contains a set of additional mutations that may affect its ability to be recognized by antibodies.
- The Delta (B.1.617.2) variant was identified in India. The Delta variant causes more infections and spreads faster than early forms of SARS-CoV-2.
- South Africa identified the variant Omicron (B.1.1.529) in November 2021. There is an increased risk of reinfection with Omicron, as compared to other variants of concern. Omicron is more transmissible but causes less severe disease compared to Delta infections. Nonetheless, due to increased transmission of Omicron, an increase in the number of severe cases is occurring and poses a significant threat to health system capacity. There is insufficient data to comment on mortality and long-term COVID outcomes. The variant is not a single strain, but rather a family of sublineages: B.1.1.529, BA.1, BA.1.1, BA.2, BA.3, BA.4 and BA.5
These VOCs harbour many mutations, including some in the receptor-binding domain (RBD) of the spike (S) protein, encoded by the S gene. Mutations in SARS-CoV-2 arise naturally through viral replication.
- Government of Canada introduces additional measures to address COVID-19 Omicron variant of concern
- Statement on the Omicron variant of concern found in Ontario
COVID-19 Variants of Concern -Guidelines, Policies and Standards
Canadian and International guidelines, policies and standards with regards to COVID-19 Variants of Concern that Infection Prevention and Control professionals may use to support their own documentation and best practices during the COVID-19 Pandemic.
- Ask Ontario’s Science Table: Omicron Edition
- SARS-CoV-2 variants: National definitions, classifications and public health actions (PHAC)
- COVID-19 Variants of Concern (VOCs) (PHO)
- Statement on the variants of COVID-19 virus found in the United Kingdom and South Africa (PHAC)
- Living Summary of SARS-CoV-2 Alpha, Beta and Gamma Variants of Concern (PHAC)
- PIDAC Interim Guidance for Infection Prevention and Control of SARS-CoV-2 Variants of Concern for Health Care Settings (PIDAC)
- COVID-19 Variant of Concern: Case, Contact and Outbreak Management Interim Guidance (Ministry of Health)
- COVID-19 P.1 Variant of Concern– What We Know So Far (PIDAC)
- Evidence on Public Health Measures Required for Rapid Control of Variants of Concern (PIDAC)
- Lockdown Duration and Re-opening including Considerations for COVID-19 Variants of Concern (PIDAC)
- SARS-CoV-2 Variants of Concern: Results of Point Prevalence Study (PIDAC)
- Using COVID-19 Data to Inform Reopening Decision-making in the Context of Variants of Concern (PIDAC)
- COVID-19 UK Variant VOC-202012/01 – What We Know So Far (PIDAC)
- COVID-19 Variants (BCCDC)
- Variants COVID-19 (AHS)
- Tracking SARS-CoV-2 Variants (WHO)
- SARS-CoV-2 Variant Classifications and Definitions (CDC)
- New Variants of the Virus that Causes COVID-19 (CDC)
- Update on COVID-19 in Canada: Epidemiology and ModellingCOVID-19 Variant of Concern Omicron (B.1.1.529): Risk Assessment
- COVID-19 Case, Contact and Outbreak Management Interim Guidance: Omicron Surge
- Update with Consideration of Omicron – Interim COVID-19 Infection Prevention and Control Government of Canada announces additional measures to contain the spread of the Omicron variant in the health care setting when COVID-19 is suspected or confirmed