Emergence and Global Spread of SARS-CoV-2 Variants
With the extended COVID-19 pandemic, SARS-CoV-2 is evolving, and multiple COVID-19 variants are circulating globally. Since December, 2020, a great deal of attention has been focused on emergence of SARS-CoV-2 variants from the UK (VOC 202012/01; B1.1.7. lineage) and from South Africa (20C/501Y.V2; B.1.351 lineage). In the UK, a new variant emerged with an unusually large number of mutations and has spread rapidly in the UK. In September, 2020, this variant represented just one in four new diagnoses of COVID-19, whereas by mid-December, this had increased to almost two thirds of new cases in London (1). Currently, the variant has been detected in at least 41 different countries. The South African variant was first detected in the Nelson Mandela Bay metropolitan area of the Eastern Cape province of South Africa (2). As the variant spreads faster than other earlier variants of the virus, the variant may be driving the second wave of the pandemic in the country. Preliminary epidemiologic, modelling, phylogenetic and clinical findings suggest that the variants have increased transmissibility.
- Kirby, T. New variant of SARS-CoV-2 in UK causes surge of COVID-19. Lancet DOI:https://doi.org/10.1016/S2213-2600(21)00005-9
- Emerging SARS-CoV-2 Variants. Available at: https://www.cdc.gov/coronavirus/2019-ncov/more/science-and-research/scientific-brief-emerging-variants.html.
- Korber et al., Tracking Changes in SARS-CoV-2 Spike: Evidence that D614G Increases Infectivity of the COVID-19 Virus. Cell 182, 812-827 e819 (2020).
- Lorenzo-Redondo et al., A Unique Clade of SARS-CoV-2 Viruses is Associated with Lower Viral Loads in Patient Upper Airways. medRxiv, (2020).
- Xie et al., Neutralization of N501Y mutant SARS-CoV-2 by BNT162b2 vaccine-elicited sera. bioRxiv, 2021.2001.2007.425740 (2021).
- J. Greaney et al., Comprehensive mapping of mutations to the SARS-CoV-2 receptor-binding domain that affect recognition by polyclonal human serum antibodies. bioRxiv, 2020.2012.2031.425021 (2021).
- M. Voloch et al., Genomic characterization of a novel SARS-CoV-2 lineage from Rio de Janeiro, Brazil. medRxiv, 2020.2012.2023.20248598 (2020).
- Kidd et al., S-variant SARS-CoV-2 is associated with significantly higher viral loads in samples tested by ThermoFisher TaqPath RT-QPCR. medRxiv, 2020.2012.2024.20248834 (2020).
- Lopez-Rincon et al., Design of Specific Primer Set for Detection of B.1.1.7 SARS-CoV-2 Variant using Deep Learning. bioRxiv, 2020.2012.2029.424715 (2020).
- Gu et al., Adaptation of SARS-CoV-2 in BALB/c mice for testing vaccine efficacy. Science 369, 1603-1607 (2020).