December 20, 2021
- Delta dominance - Delta remains the predominant variant accounting for most of variants sequenced from surveillance data from Public Health Ontario, Public Health England and ECDC as of the 6th of December; this is rapidly changing.
- Expect opinions from PHAC indicate that Omicron will likely outpace Delta and drive infections up to 26,600 a day by mid-January in Canada.
- ECDC projects Omicron could cause over half of all SARS-CoV-2 infections in the EU/EEA within the next few months, with probability of further introduction and community spread and impact of the spread assessed HIGH and VERY HIGH respectively.
- Preliminary evidence suggests that the various mutations in Omicron may increase transmissibility and replication; increase evasion of antibody neutralization by COVID-19 infection, vaccine-based, or monoclonal-based antibodies; increase the binding affinity of the virus to the ACE2 receptors on host cells; and may be associated with increased infectivity.
- Evidence is still emerging on the disease severity with omicron compared to Delta, however the first Omicron death has been reported in the UK during the week of December 13, 2021.
- The Delta sub-lineage AY.4.2 (Delta plus) continues account for an increasing proportion of Delta cases in the UK, with cases detected in Canada.
December 6, 2021
- A new SARS-CoV-2 variant designated Omicron has emerged and classified as a VOC by WHO. The heavily mutated variant (50 mutations -- 32 of them on the spike protein) was first identified in South Africa and has already spread to many parts of the world.
- Preliminary evidence suggests there may be an increased risk of reinfection with Omicron, however, there is still emerging evidence of the transmissibility, severity of disease, effectiveness of vaccines, and the effectiveness of current tests and treatment.
- Delta dominance - Delta remains the predominant variant accounting for most of variants sequenced from surveillance data from Public Health Ontario, Public Health England and ECDC.
- The Delta sub-lineage AY.4.2 (Delta plus) continues account for an increasing proportion of Delta cases in the UK.
- Delta variant sub-lineage AY.25 and AY.27 have been detected in Canada, with majority of the cases identified in Saskatchewan, followed by Alberta and B.C. However, experts say there’s no data to determine if these sub-lineages will be more transmissible than its parent strain.
Asamoah, G; Badea, A; Lee, S; Shumilak, G; Reeder, B; Groot, G; Muhajarine, N; Hernandez-Ronquillo L; Miller, L; Howell-Spooner, B. What is the epidemiology of variants and what are the implications for healthcare? 2021 Dec 20. Document no.: EOC031801v019 RR. In: COVID-19 Rapid Evidence Reviews [Internet]. SK: SK COVID Evidence Support Team, c2021. 50 p. (CEST rapid review report).