COVID-19- Variants of Concern (VOC)

Last Reviewed/Updated: 10:03 a.m., June 28, 2021


Variants are viruses that have changed or mutated. Multiple variants of the virus that causes COVID-19 have been found around the world. A variant becomes a Variant of Concern (VOC) when its changes affect one or more of the following factors:

  • Spreads more easily and quickly than other strains of COVID-19
  • Causes more severe illness
  • Doesn’t respond to diagnostic tests, treatment or vaccines in the same way as the original strain

To learn more about how to reduce your risk, click here. For information on the local COVID-19 variant cases, visit the Local COVID-19 Tracker.

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COVID-19 Variants of Concern – Ontario
What are the COVID-19 variants?
How is a VOC identified?
Preventing the transmission of VOCs
What is PPH doing to protect against the variants?


What are the COVID-19 variants

Four variants of concern have been identified:

Alpha (B.1.1.7)

  • Detected in Ontario in December 2020.
  • Spreads more easily (53-82% more transmissible).
  • Increased severity of disease with a higher risk of hospitalization and death.
  • Both Pfizer and Moderna indicated that their COVID-19 vaccines appear to be effective against the Alpha variant. This is likely because the part of the virus that changed doesn’t impact how the vaccine works.

Beta (B.1.351)

  • Detected in Ontario in February 2021.
  • Spreads more easily (50% more transmissible).
  • May escape impact of a vaccine and evade the immune response.

Gamma (P.1)

  • May escape impact of a vaccine and evade the immune response.

Delta (B.1.617.2)

  • There are different sublineages associated with this variant: B.1.67.1, B.1.67.2, B.1.67.3
  • Two lineages (B.1.67.1 and B.1.67.2) spreads more easily.
  • About 50% more transmissible than the Alpha variant.

Experts continue to study how the virus is changing by understanding its genetic make-up.  This will help us understand how changes to the virus might affect how it spreads, or how it presents in people.

For up-to-date information on the number of variant cases in Ontario see the daily summary of cases in Ontario.

How is a VOC identified?

Peterborough Public Health and the Public Health Ontario Labs are watching closely for any VOCs.  Once a positive COVID-19 test is received it is screened for VOCs.  This process can take 1-2 days.  Due to the delay, PPH is treating all positive cases of COVID-19 as a VOC for contact tracing and management purposes.  By doing so, PPH will be able to respond more quickly if the COVID-19 test screens positive for a variant.

If the test does screen positive for a VOC, then the Public Health Ontario Lab carries out genomic sequencing to determine the precise variant.  Genomic sequencing can take up to 14 days.

The first case of a variant in Peterborough was identified on February 23, 2021.  For more information on the local COVID-19 variant cases, visit the Local COVID-19 Tracker.

Preventing the transmission of VOCs

Everyone is encouraged to continue following all public health measures to prevent the transmission of COVID-19 and its variants. This includes:

  • Maintaining 2-metres of distance from non-household members
  • Wearing a mask when distancing is not possible – even outdoors
  • Practicing hand hygiene
  • Covering coughs and sneezes
  • Disinfecting high touch surfaces

To learn more about how to reduce your risk click on: COVID-19 – Prevention

If you suspect that you have been in contact with a case of COVID-19, or you are experiencing COVID-19 symptoms, seek testing and isolate until you receive your test results.  Once you do receive the results, follow the public health recommendations associated with your diagnosis.

What is PPH doing to protect against variants?

PPH is closely watching for variants locally, and is currently working with local partners to ramp up vaccinations of high-risk populations.  PPH is also implementing the provincial guidance for strengthening measures we know work, including identifying high risk contacts and more intense outbreak management if a variant does occur in a high-risk setting, such as a school or workplace.