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Viruses constantly change through mutation, and new variants of a virus are expected to occur. Sometimes new variants emerge and disappear. COVID-19疫情自2019年底被发现以来，造成大量人群的感染。伴随着感染人数的增加和疫情的持续，SARS-CoV-2不断进化和变异，产生了大量的病毒变异株，其中一些变异株的传播能力和致病性明显提高，还有一些毒株出现抗原逃逸现象，这些变异株引起了公共卫生部门和民众的关注。Other times, new variants persist. Multiple variants of the virus that causes COVID-19 have been documented in the United States and globally during this pandemic. Genetic variants of SARS-CoV-2 have been emerging and circulating around the world throughout the COVID-19 pandemic. A US government SARS-CoV-2 Interagency Group (SIG) interagency group developed a Variant Classification scheme that defines three classes of SARS-CoV-2 variants:
The B.1.1.7 (Alpha), B.1.351 (Beta), B.1.617.2 (Delta), and P.1 (Gamma), variants circulating in the United States are classified as variants of concern.
To date, no variants of high consequence have been identified in the United States.
L452R is present in B.1.526 (Iota), B.1.427 (Epsilon), and B.1.429 (Epsilon) lineages, as well as the B.1.617 (Kappa, Delta) lineages and sub-lineages. E484K is present in B.1.525 (Eta), P.2 (Zeta), P.1 (Gamma), and B.1.351 (Beta), but only some strains of B.1.526 (Iota) and B.1.1.7 (Alpha). The combination of K417N, E484K, and N501Y substitutions is present in B.1.351 (Beta). The combination of K417T, E484K, and N501Y substitutions is present in P.1 (Gamma).
Viruses constantly change through mutation. A variant has one or more mutations that differentiate it from other variants in circulation. As expected, multiple variants of SARS-CoV-2 have been documented in the United States and globally throughout this pandemic. To inform local outbreak investigations and understand national trends, scientists compare genetic differences between viruses to identify variants and how they are related to each other. Variant classificationsThe US Department of Health and Human Services (HHS) established a SARS-CoV-2 Interagency Group (SIG) to improve coordination among the Centers for Disease Control and Prevention (CDC), National Institutes of Health (NIH), Food and Drug Administration (FDA), Biomedical Advanced Research and Development Authority (BARDA), and Department of Defense (DoD). This interagency group is focused on the rapid characterization of emerging variants and actively monitors their potential impact on critical SARS-CoV-2 countermeasures, including vaccines, therapeutics, and diagnostics. Variant of Concern (VOC)– View current VOC in the United States that are being closely monitored and characterized by federal agencies
Notes: Each classification of variant includes the possible attributes of lower classes (i.e., VOC includes the possible attributes of VOI); variant status might escalate or deescalate based on emerging scientific evidence. This page will be updated as needed to show the variants that belong to each class. The World Health Organizationexternal icon (WHO) also classifies variant viruses as Variants of Concern and Variants of Interest; US classifications may differ from those of WHO because the importance of variants may differ by location. To assist with public discussions of variants, WHO proposed using labels consisting of the Greek Alphabet, i.e., Alpha, Beta, Gamma, as a practical way to discuss variants by non-scientific audiences. The labels assigned to each variant are provided in the tables below. Variant of InterestA variant with specific genetic markers that have been associated with changes to receptor binding, reduced neutralization by antibodies generated against previous infection or vaccination, reduced efficacy of treatments, potential diagnostic impact, or predicted increase in transmissibility or disease severity. Possible attributes of a variant of interest: Specific genetic markers that are predicted to affect transmission, diagnostics, therapeutics, or immune escape. Evidence that it is the cause of an increased proportion of cases or unique outbreak clusters. Limited prevalence or expansion in the US or in other countries.
A variant of interest might require one or more appropriate public health actions, including enhanced sequence surveillance, enhanced laboratory characterization, or epidemiological investigations to assess how easily the virus spreads to others, the severity of disease, the efficacy of therapeutics and whether currently authorized vaccines offer protection. Current variants of interest in the United States that are being monitored and characterized are listed below. This will be updated when a new variant of interest is identified. Selected Characteristics of SARS-CoV-2 Variants of InterestSpike Protein Substitutions: L452R, D614G WHO Label: Epsilon First Identified: United States-(California) 美国加州变异株 Attributes: ~20% increased transmission21 Modest decrease in susceptibility to the combination of bamlanivimab and etesevimab; however, the clinical implications of this decrease are not known.7 Alternative monoclonal antibody treatments are available.14 Reduced neutralization by convalescent and post-vaccination sera21 Deescalated from a VOC on June 29, 2021, due to the significant decrease in the proportion of B.1.427 lineage viruses circulating nationally and available data indicating that vaccines and treatments are effective against this variant.
Spike Protein Substitutions: S13I, W152C, L452R, D614G WHO Label: Epsilon First Identified: United States-(California) 美国加州变异株 Attributes: ~20% increased transmission21 Reduced susceptibility to the combination of bamlanivimab and etesevimab; however, the clinical implications of this decrease are not known.7 Alternative monoclonal antibody treatments are available.14 Reduced neutralization by convalescent and post-vaccination sera21. Deescalated from a VOC on June 29, 2021, due to the significant decrease in the proportion of B.1.429 lineage viruses circulating nationally and available data indicating that vaccines and treatments are effective against this variant.
Spike Protein Substitutions: A67V, 69del, 70del, 144del, E484K, D614G, Q677H, F888L WHO Label: Eta First Identified: United Kingdom/Nigeria – December 2020 尼日利亚变异株 Attributes: Potential reduction in neutralization by some Emergency Use Authorization (EUA) monoclonal antibody treatments 7, 14 Potential reduction in neutralization by convalescent and post-vaccination sera22
Spike Protein Substitutions: L5F, (D80G*), T95I, (Y144-*), (F157S*), D253G, (L452R*), (S477N*), E484K, D614G, A701V, (T859N*), (D950H*), (Q957R*) WHO Label: Iota First Identified: United States (New York) – November 2020 美国纽约变异株 Attributes: Reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment; however, the clinical implications of this are not known.7 Alternative monoclonal antibody treatments are available.14 Reduced neutralization by convalescent and post-vaccination sera22, 24 B.1.526.1 sublineage has been consolidated with this parent lineage
Spike Protein Substitutions: (T95I), G142D, E154K, L452R, E484Q, D614G, P681R, Q1071H WHO Label: Kappa First Identified: India – December 2020 印度变异株 Attributes: Potential reduction in neutralization by some EUA monoclonal antibody treatments7, 14 Potential reduction in neutralization by post-vaccination sera26
Spike Protein Substitutions: T19R, G142D, L452R, E484Q, D614G, P681R, D950N First Identified: India – October 2020 印度变异株 Attributes: Potential reduction in neutralization by some EUA monoclonal antibody treatments7, 14 Potential reduction in neutralization by post-vaccination sera26
Spike Protein Substitutions: E484K, (F565L*), D614G, V1176F WHO Label: Zeta First Identified: Brazil – April 2020 巴西变异株 Attributes: Potential reduction in neutralization by some EUA monoclonal antibody treatments7, 14 Reduced neutralization by post-vaccination sera22, 23
Variant of ConcernA variant for which there is evidence of an increase in transmissibility, more severe disease (e.g., increased hospitalizations or deaths), significant reduction in neutralization by antibodies generated during previous infection or vaccination, reduced effectiveness of treatments or vaccines, or diagnostic detection failures. Possible attributes of a variant of concern: In addition to the possible attributes of a variant of interest Evidence of impact on diagnostics, treatments, or vaccines
Widespread interference with diagnostic test targets Evidence of substantially decreased susceptibility to one or more class of therapies Evidence of significant decreased neutralization by antibodies generated during previous infection or vaccination Evidence of reduced vaccine-induced protection from severe disease
Evidence of increased transmissibility Evidence of increased disease severity
Variants of concern might require one or more appropriate public health actions, such as notification to WHO under the International Health Regulations, reporting to CDC, local or regional efforts to control spread, increased testing, or research to determine the effectiveness of vaccines and treatments against the variant. Based on the characteristics of the variant, additional considerations may include the development of new diagnostics or the modification of vaccines or treatments. Current variants of concern in the United States that are being closely monitored and characterized by federal agencies are included in the below. This table will be updated when a new variant of concern is identified. Selected Characteristics of SARS-CoV-2 Variants of ConcernSpike Protein Substitutions: 69del, 70del, 144del, (E484K*), (S494P*), N501Y, A570D, D614G, P681H, T716I, S982A, D1118H (K1191N*) WHO Label: Alpha First Identified: United Kingdom 英国变异株 N501Y.V1 Attributes: ~50% increased transmission5 Potential increased severity based on hospitalizations and case fatality rates6 No impact on susceptibility to EUA monoclonal antibody treatments7,14 Minimal impact on neutralization by convalescent and post-vaccination sera8-13,19
Spike Protein Substitutions: D80A, D215G, 241del, 242del, 243del, K417N, E484K, N501Y, D614G, A701V WHO Label: Beta First Identified: South Africa 南非变异株 N501Y.V2 Attributes: ~50% increased transmission16 Significantly reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment,7 but other EUA monoclonal antibody treatments are available 14 Reduced neutralization by convalescent and post-vaccination sera8,12,18,19,20
Spike Protein Substitutions: T19R, (V70F*), T95I, G142D, E156-, F157-, R158G, (A222V*), (W258L*), (K417N*), L452R, T478K, D614G, P681R, D950N WHO Label: Delta First Identified: India 印度德尔塔变异株 Attributes: Increased transmissibility 29 Potential reduction in neutralization by some EUA monoclonal antibody treatments 7, 14 Potential reduction in neutralization by post-vaccination sera 21 AY.1 and AY.2 are currently aggregated with B.1.617.2. As data are available, CDC will continue to evaluate the independent classification of AY.1 and AY.2.
Spike Protein Substitutions: L18F, T20N, P26S, D138Y, R190S, K417T, E484K, N501Y, D614G, H655Y, T1027I WHO Label: Gamma First Identified: Japan/Brazil 巴西变异株 N501Y.V3 Attributes: Significantly reduced susceptibility to the combination of bamlanivimab and etesevimab monoclonal antibody treatment,7 but other EUA monoclonal antibody treatments are available 14 Reduced neutralization by convalescent and post-vaccination sera15
Variant of High ConsequenceA variant of high consequence has clear evidence that prevention measures or medical countermeasures (MCMs) have significantly reduced effectiveness relative to previously circulating variants. Possible attributes of a variant of high consequence: In addition to the possible attributes of a variant of concern A variant of high consequence would require notification to WHO under the International Health Regulations, reporting to CDC, an announcement of strategies to prevent or contain transmission, and recommendations to update treatments and vaccines. Currently, there are no SARS-CoV-2 variants that rise to the level of high consequence.
Treatment considerations for healthcare providersSubstitutions of Concern for SARS-CoV-2 Monoclonal Antibody Therapies CDC’s national genomic surveillance program identifies new and emerging SARS-CoV-2 variants to determine implications for COVID-19 diagnostics, treatments, or vaccines authorized for use in the United States. Sequences with similar genetic changes are grouped into lineages, and multiple lineages can have the same substitutions. For example, the E484K substitution is found in lineages B.1.351, P.1, B.1.526, and many others. Genomic surveillance efforts provide the capability to detect viruses that have reduced susceptibility to treatments more quickly. In laboratory studies, SARS-CoV-2 variants that contain certain substitutions in the spike protein cause a marked reduction in susceptibility to bamlanivimab and may have reduced sensitivity to etesevimab and casirivimab. The L452R substitution found in the B.1.427 and B.1.429 lineages has been shown to cause a significant reduction in susceptibility to bamlanivimab and a modest decrease in susceptibility to the combination of bamlanivimab and etesevimab, although the clinical implications of this modest decrease are not known. 7 The E484K substitution found in the B.1.351, P.1, and B.1.526 lineages also results in a marked reduction in susceptibility to bamlanivimab, as well as the combination of bamlanivimab and etesevimab.7 Laboratory studies also suggest that the K417N and K417T substitutions, which are present in the B.1.351 and P.1 variants, respectively, along with the E484K mutation, reduces virus susceptibility to casirivimab, although the combination of casirivimab and imdevimab appears to retain activity.14 There is no reported reduction in susceptibility of variants to sotrovimab.28 The data below shows the national and regional unweighted proportions of SARS-CoV-2 that contain the L452R or E484K substitution, individually, as well as the unweighted proportions of SARS-CoV-2 that contain the combination of K417N, E484K, and N501Y substitutions or the combination of K417T, E484K, and N501Y substitutions. As new data become available, additional substitutions may be added below.
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发表于 2021-7-9 12:33:52
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