Covid-19 Variants
All viruses, including SARS-CoV-2, the virus that causes COVID-19, change over time.
Most changes have little to no impact on the virus’ properties. However, some changes may affect the virus’s properties, such as how easily it spreads, the associated disease severity, or the performance of vaccines, therapeutic medicines, diagnostic tools, or other public health and social measures.
WHO, in collaboration with partners, expert networks, national authorities, institutions and researchers have been monitoring and assessing the evolution of SARS-CoV-2 since January 2020. During late 2020, the emergence of variants that posed an increased risk to global public health prompted the characterisation of specific Variants of Interest (VOIs) and Variants of Concern (VOCs), in order to prioritize global monitoring and research, and ultimately to inform the ongoing response to the COVID-19 pandemic.
A variant of interest
A SARS-CoV-2 VARIANT
With genetic changes that are predicted or known to affect virus characteristics such as transmissibility, disease severity, immune escape, diagnostic or therapeutic escape; AND
Identified to cause significant community transmission or multiple COVID-19 clusters, in multiple countries with increasing relative prevalence alongside an increasing number of cases over time, or other apparent epidemiological impacts to suggest an emerging risk to global public health.
There is no currently circulating variant of interest (VOI). previously circulating VOI
A VARIANT OF CONCERN
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A SARS-CoV-2 variant that meets the definition of a VOI (see below) and, through a comparative assessment, has been demonstrated to be associated with one or more of the following changes at a degree of global public health significance:
• Increase in transmissibility or detrimental change in COVID-19 epidemiology; OR
• Increase in virulence or change in clinical disease presentation; OR
• Decrease in effectiveness of public health and social measures or available diagnostics, vaccines, therapeutics.
Variants under monitoring (VUM)
A SARS-CoV-2 variant with genetic changes that are suspected to affect virus characteristics with some indication that it may pose a future risk, but evidence of phenotypic or epidemiological impact is currently unclear, requiring enhanced monitoring and repeat assessment pending new evidence.
There is currently no variant under monitoring
Note: It is expected that our understanding of the impacts of these variants may fast evolve, and designated Variants under Monitoring may be readily added/removed; therefore, WHO labels will not be assigned at this time. Former VOIs/VOCs may, however, be monitored for an extended period under this category, and will maintain their assigned WHO label until further notice.
For up-to-date information about the Covid situation in the world
To date 5 variants
of concern have been identified
in Alberta
The B.1.1.529 (Omicron) variant and its descendants are the dominant strain in Alberta. Anyone who has been infected with a variant strain will test positive for COVID-19. Positive tests are screened again for all variants to determine the exact strain.
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First identified in the United Kingdom, research has shown this variant spreads more easily and can cause more severe illness in comparison to the original
COVID-19 strain.
ALPHA
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First identified in South Africa, research has shown this variant spreads more easily than the original COVID-19 strain and may be capable of re-infecting people who have previously tested positive for COVID-19.
BETA
GAMMA
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First identified in Brazil, research has shown this variant spreads more easily than the original COVID-19 strain and is capable of re-infecting people who have previously tested positive for COVID-19.
DELTA
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First identified in India, research has shown this variant spreads more easily than the Alpha variant and causes an increased risk of hospitalization and re-infection of people who have previously tested positive for COVID-19.
OMICRON
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First identified in South Africa, this has been the most common variant in Alberta and worldwide throughout 2022. It is the dominant strain globally because it spreads easily. Omicron continues to acquire new mutations as it spreads.
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These mutations are not different enough from Omicron to be considered new variants. Instead, they are referred to as subvariants. Some examples of Omicron subvariants are BA.2, BA.4, and BA.5. They are closely related to the original Omicron strain, but have slight differences. Evidence suggests Omicron and its subvariants are more infectious so people who have been previously infected with COVID-19 can be reinfected more easily.
As Omicron spread globally, we learned that the risk of severe disease is reduced compared to the Delta variant. However, the increased transmission means many more people have become infected, which has caused significant impact on individuals and health systems. As with all COVID-19 variants, the risk of disease severity may depend on other factors, such as age and chronic disease.
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