Living Evidence - SARS-CoV-2 variants
Living evidence tables provide high level summaries of key studies and evidence on a particular topic, and links to sources. They are reviewed daily and updated as new evidence and information is published.
Viruses constantly change through mutation and over time, new variants of a virus are expected to occur. Some variants have characteristics that have a significant impact on transmissibility, severity of disease and effectiveness of vaccines. This table includes information on variants that are currently causing concern in the scientific community.
Currently there are three variants of concern – all have the N501Y mutation - a change from asparagine (N) to tyrosine (Y) at amino-acid site 501.
| B.1.1.7 | B.1.351 | B.1.1.28.1 (P.1) | |
|---|---|---|---|
| Alternate names |
501Y.V1 Variant of Concern (VOC)-202012/01 "Kent variant" | 501Y.V2 Variant of Concern (VOC) – 202012/02 |
501Y.V3
Variant of Concern (VOC) – 202101/02 |
| First detected | UK September 2020 | South Africa December 2020 | Brazil December 2020 |
| Mutations |
23 (17 of which change amino acids)
Includes N501Y substitution |
21 Includes N501Y substitution |
17 (11 of which change amino acids)
Includes N501Y substitution |
| Transmissibility compared with wild type | Estimated 43–90% higher reproduction number than wild type.* Estimated transmission advantage at warmer temperatures than wild type *^ Estimated that the N501Y substitution increases the infectivity by 52%. | Estimated transmissibility is 2.5 times greater than wild type*^ Estimated that the N501Y substitution increases the infectivity by 52%. | Estimated 1.4–2.2 times more transmissible than other lineages.^ Estimated that the N501Y substitution increases the infectivity by 52%. |
| Virulence / severity or duration of disease compared with wild type | Conflicting evidence, with studies showing no association between severe disease and death* or symptoms or disease burden* and one study showing estimated risk of mortality is increased (from 2.5 to 4.1 deaths per 1,000 cases) in low risk groups* Estimated increases in relative hazard and absolute risk of death*^ Average infections last 13.3 days compared with 8.2 days for other variants*^ | No data to suggest increased mortality^ | Not established |
| Immune escape (vaccines / previous infections will not be protective) | Pfizer/BioNTech neutralisation as per wild type.^ Reduction in neutralising capacity when carrying the E484K mutation. Prior COVID-19 infection and vaccination substantially increased neutralizing activity. AstraZeneca 74.6% efficacy for prevention of symptomatic disease.^ Moderna neutralisation as per wild type.^ Novavax 86% efficacy for prevention of of symptomatic disease.^ Elicits cross-reactive neutralising antibodies.* | Pfizer/BioNTech, multiple studies show significant reduction in neutralisation of B.1.351.*^ Prior COVID-19 infection and vaccination substantially increased neutralizing activity. AstraZeneca 10.4% efficacy for prevention of symptomatic disease*^ Moderna neutralisation as per wild type* Novavax 50-60% efficacy for prevention of symptomatic disease*^ Johnson & Johnson 85% efficacy for prevention of symptomatic disease *^ Elicits cross-reactive neutralising antibodies.^ | Pfizer/BioNTech neutralisation as per wild type*^Prior COVID-19 infection and vaccination substantially increased neutralizing activity. AstraZeneca reports efficacy for prevention of symptomatic disease (news reporting on preliminary data)*^ Moderna neutralisation as per wild type *^ Estimated 6.4% reinfection probability*^ Elicits cross-reactive neutralising antibodies.^ |
| Testing and detection | PCR effective at detecting and distinguishing variant*^ Lateral flow devices effective in detecting Wastewater-based SARS-CoV-2 sequencing effective in detecting variants*^ Multiple studies report reliable assays for rapid detection of variants.^ | PCR effective at detecting variant*^ Wastewater-based SARS-CoV-2 sequencing effective in detecting variants*^ Multiple studies report reliable assays for rapid detection of variants.^ | PCR effective at detecting variant*^ Wastewater-based SARS-CoV-2 sequencing effective in detecting variants*^ Multiple studies report reliable assays for rapid detection of variants.^ |
| Links with post-acute COVID-19 syndrome | Not established | Not established | Not established |
| Countries reporting detection (not necessarily local transmission) | Detected in 114 countries
Dominant strain in UK and estimated to account for ~95% of new infections in England and increasing at a rate of 7.5% per day in the US.^ |
Detected in 68 countries
Dominant strain in South Africa |
Detected in 37 countries Dominant strain in Brazil Rapid spread in British Columbia |
Details are tabulated when variants meet the World Health Organisation definition of variants of concern.
Reports of variants in grey literature and documented as variants under investigation (VUI) or in monitoring are below:
- Reports of increasing number of lineages containing the E484K substitution*^ The ‘Bristol Variant’ has emerged from the B.1.1.7 variant and contains the mutation*
- P.2 is a VUI with B.1.1.28 lineage and has S:E484K mutation. This variant is spreading in Brazil
- Reports of VUI-202102/04 (B.1.1.318) first identified in the UK in February 2021^
- A new variant (B.1.2/20G clade) “Robin” in October 2020; now detected in 30 states in the US.
- Reports of VUI-202102/03 (B.1525) first identified in the UK in February 2021 and other countries^
- A variant (CAL.20C) identified in Southern California in July 2020. The variant spans the B.1.427 and B.1.429 lineages, with reports of 18.6-24% increase in transmissibility relative to wild-type circulating strains and decreased antibody neutralization^* Carries the L452R mutation. The Centers for Disease Control and Prevention are calling it a VOC, however US classifications may differ from those of WHO.
Notes
*Preliminary data, not fully established, in some cases small numbers or short follow up; interpret with caution
^ Commentary grey literature, pre peer review or news
Background
Living evidence tables include some links to low quality sources and an assessment of the original source has not been undertaken. Sources are monitored daily but due to rapidly emerging information, tables may not always reflect the most current evidence. The tables are not peer reviewed, and inclusion does not imply official recommendation nor endorsement of NSW Health.
Last updated on 14 Apr 2021