Early warning and response surveillance (EWARS) systems were widely used during the early COVID-19 response. Evaluating the effectiveness of EWARS systems is critical to ensuring global health security. We describe the Centers for Disease Control and Prevention (CDC) global COVID-19 EWARS (CDC EWARS) system and the resources CDC used to gather, manage, and analyze publicly available data during the prepandemic period. We evaluated data quality and validity by measuring reporting completeness and compared these with data from Johns Hopkins University, the European Centre for Disease Prevention and Control, and indicator-based data from the World Health Organization. CDC EWARS was integral in guiding CDC’s early COVID-19 response but was labor-intensive and became less informative as case-level data decreased and the pandemic evolved. However, CDC EWARS data were similar to those reported by other organizations, confirming the validity of each system and suggesting collaboration could improve EWARS systems during future pandemics.

在 COVID-19 早期响应期间，早期预警和响应监视 (EWARS) 系统被广泛使用。评估 EWARS 系统的有效性对于确保全球卫生安全至关重要。我们描述了疾病控制和预防中心 (CDC) 的全球 COVID-19 EWARS (CDC EWARS) 系统以及 CDC 在大流行前用于收集、管理和分析公开可用数据的资源。我们通过衡量报告的完整性来评估数据质量和有效性，并将这些数据与约翰霍普金斯大学、欧洲疾病预防控制中心的数据以及世界卫生组织的基于指标的数据进行比较。CDC EWARS 在指导 CDC 早期应对 COVID-19 方面发挥了不可或缺的作用，但它是劳动密集型的，并且随着病例级数据的减少和大流行的演变，信息量也越来越少。然而，