Variants of Concern vs. Variants of Interest
Variants of concern (VOCs) are mutations of SARS-CoV-2 that are confirmed to be more infectious, can potentially cause more severe disease, and may be more resistant to existing vaccines compared to the original strain. CoVaRR-Net is working alongside other organizations in Canada and around the world to investigate VOCs and emerging new variants.
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. XBB.1.5 is one of the currently fastest growing lineages worldwide (January 2023).
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 (July 2023) include XBB.1.5 and XBB.1.16 and EG.5 (a descendant of XBB.1.9.2). 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 (August 2023) include BA.2.75, CH.1.1, BQ.1, XBB, XBB.1.9.1, XBB.1.9.2, XBB.2.3 and BA.2.86.
Simplified SARS-CoV-2 evolutionary tree