What are Variants?
When viruses infect cells and replicate their genetic material, errors occur. While many of these errors, or genetic mutations, have little effect, some can be harmful to the virus. Others can cause small changes in viral proteins and give viruses new abilities. These abilities can include making the virus more infectious, more resistant to vaccines and therapies, and sometimes making our antibodies or immune systems less effective against these modified viruses. Viruses containing genetic mutations are called variants, and those with a suspected or confirmed advantage are called variants of interest and variants of concern, respectively.
Variants continue to emerge as long as the virus is able to spread to new hosts. Vaccines train our immune system to recognize different parts of the virus before we get infected. Therefore, if mutations change the parts used for this training, vaccines become less effective and need to be updated. This is why variants must be tracked and analyzed continuously.
What are Variants?
When viruses infect cells and replicate their genetic material, errors occur during this process. While many of these errors, or genetic mutations, have little effect, some can be harmful to the virus. Others can cause small changes in viral proteins and give viruses new abilities. These abilities can include making the virus more infectious, more resistant to vaccines and therapies, and sometimes making our antibodies or immune systems less effective against these modified viruses. Viruses containing genetic mutations are called variants, and those with a suspected or confirmed advantage are called variants of interest and variants of concern, respectively.
Variants continue to emerge as long as the virus is able to spread to new hosts. Vaccines train our immune system to recognize different parts of the virus before we get infected. Therefore, if mutations change the parts used for this training, vaccines become less effective and need to be updated. This is why variants must be tracked and analyzed continuously.
Variants of Concern vs. Variants of Interest
SARS-CoV-2 variants of concern (VOC) have newly acquired mutations that can potentially lead to more severe disease, and may make the variant more resistant to existing vaccines compared to the original strain. Continuously tracking and analyzing variants is crucial as this helps prepare us for new mass outbreaks and hospitalization waves, and offers forewarning when updated vaccines are needed. CoVaRR-Net’s mission was to rapidly answer critical and immediate questions regarding COVID-19 variants, such as their increased transmissibility, likelihood to cause severe cases of COVID-19, and resistance to vaccines. The CoVaRR-Net team undertook extensive research throughout its four years and provided invaluable, evidence-based guidance to policymakers, healthcare professionals, and the public.
Some of its major initiatives leading the charge in tracking variants, such as the Computational Analysis, Modelling, and Evolutionary Outcomes (CAMEO) initiative and the Wastewater Surveillance Research Group are continuing pending new funding sources.
There is currently only one circulating VOC in Canada: Omicron, which has become the dominant variant in Canada and around the world. Its parent lineage, B.1.1.529, was first reported to the WHO from South Africa in late November 2021. Omicron now includes BA.1, BA.2, BA.3, BA.4, BA.5 and descendent lineages. It also includes circulating recombinant forms such as BQ and XBB. Currently, JN.1 (BA.2.86 descendent) is the fastest growing lineage (February 2024).
A variant of interest (VOI) is one that is only “suspected” to either be more contagious than the initial strain, cause more severe disease, or escape the protection offered by vaccines. A VOI can become a VOC if more scientific and clinical evidence emerges that it acquires one or more of these attributes.
According to the World Health Organization (WHO), currently circulating VOIs (as of December 02, 2024) include JN.1. Previously circulating VOIs include Eta (B.1.525), Kappa (B.1.617.1), Iota (B.1.526), Epsilon (B.1.427/B.1.429), Zeta (P.2), Theta (P.3), Lambda (C.37) and Mu (B.1.621).
A variant under monitoring (VUM) is a SARS-CoV-2 variant with genetic changes that are suspected to pose a future risk. It is important to carefully monitor and repeatedly assess VUMs until evidence of their impact is clear. According to the WHO, currently circulating VUMs (as of February 3, 2025) include KP.2, KP.3, KP.3.1.1, JN.1.18, LB.1, XEC and LP.8.1.
Simplified Evolutionary Tree of SARS-CoV-2 Variants in Canada
WHO:
The World Health Organization started May 31, 2021 to give Greek letters (e.g., Alpha, Beta, Gamma, and Delta) according to the order of the detection of variants.
PANGO:
Phylogenetic Assignment of Named Global Outbreak, a nomenclature system defining the dynamic nomenclature of SARS-CoV-2 lineages.
Clade:
A group of genetically similar viruses derived from a common ancestor.