SARS-CoV-2 Variant Proportions

To identify and track SARS-CoV-2 variants, CDC uses genomic surveillance. CDC's national genomic surveillance system collects SARS-CoV-2 specimens for sequencing through the National SARS-CoV-2 Strain Surveillance (NS3) program, as well as SARS-CoV-2 sequences generated by commercial or academic laboratories contracted by CDC and state or local public health laboratories. Viral genomic sequences are analyzed and classified as a particular variant. The proportions of variants in a population are estimated nationally, by HHS region, and by jurisdiction. The thousands of sequences analyzed every week through CDC’s national genomic sequencing and bioinformatics efforts fuel this comprehensive and population-based U.S. surveillance system established to identify and monitor the spread of variants.

These data appear on the CDC COVID Data Tracker at the following URL: <a href="https://covid.cdc.gov/covid-data-tracker/#variant-proportions">https://covid.cdc.gov/covid-data-tracker/#variant-proportions</a>

For more information on how these data are generated and used to provide estimates of variant proportions, please see the following references:

<ul>
<li>Paul P, France AM, Aoki Y, et al. Genomic Surveillance for SARS-CoV-2 Variants Circulating in the United States, December 2020–May 2021. MMWR Morb Mortal Wkly Rep 2021;70:846–850. DOI: <a href="http://dx.doi.org/10.15585/mmwr.mm7023a3">http://dx.doi.org/10.15585/mmwr.mm7023a3</a></li>
<li>Lambrou AS, Shirk P, Steele MK, et al. Genomic Surveillance for SARS-CoV-2 Variants: Predominance of the Delta (B.1.617.2) and Omicron (B.1.1.529) Variants — United States, June 2021–January 2022. MMWR Morb Mortal Wkly Rep 2022;71:206–211. DOI: <a href="http://dx.doi.org/10.15585/mmwr.mm7106a4">http://dx.doi.org/10.15585/mmwr.mm7106a4</a></li></ul>

为识别并追踪严重急性呼吸综合征冠状病毒2型（SARS-CoV-2）变异株，美国疾病控制与预防中心（Centers for Disease Control and Prevention，简称CDC）采用基因组监测手段开展相关工作。CDC的国家级基因组监测系统，通过国家SARS-CoV-2毒株监测（National SARS-CoV-2 Strain Surveillance，简称NS3）项目收集用于测序的SARS-CoV-2样本，同时收录由CDC签约的商业或学术实验室，以及州或地方公共卫生实验室所生成的SARS-CoV-2序列数据。研究人员会对病毒基因组序列进行分析，并将其归类为特定变异株。该系统会在全国范围、卫生与公众服务部（Health and Human Services，简称HHS）辖区以及各司法管辖区内，估算人群中各类变异株的占比。CDC每周通过国家级基因组测序与生物信息学工作分析数千条序列，为这套全面的、基于人群的美国监测系统提供核心支撑，该系统的设立初衷为识别并监测变异株的传播态势。

这些数据可在CDC新冠数据追踪平台查询，具体网址为：<a href="https://covid.cdc.gov/covid-data-tracker/#variant-proportions">https://covid.cdc.gov/covid-data-tracker/#variant-proportions</a>

如需了解这些数据的生成流程，以及其用于估算变异株占比的更多细节，请参阅以下参考文献：
<ul>
<li>Paul P, France AM, Aoki Y, et al. Genomic Surveillance for SARS-CoV-2 Variants Circulating in the United States, December 2020–May 2021. MMWR Morb Mortal Wkly Rep 2021;70:846–850. DOI: <a href="http://dx.doi.org/10.15585/mmwr.mm7023a3">http://dx.doi.org/10.15585/mmwr.mm7023a3</a></li>
<li>Lambrou AS, Shirk P, Steele MK, et al. Genomic Surveillance for SARS-CoV-2 Variants: Predominance of the Delta (B.1.617.2) and Omicron (B.1.1.529) Variants — United States, June 2021–January 2022. MMWR Morb Mortal Wkly Rep 2022;71:206–211. DOI: <a href="http://dx.doi.org/10.15585/mmwr.mm7106a4">http://dx.doi.org/10.15585/mmwr.mm7106a4</a></li></ul>