Sentinel Community-Based Surveillance: An Innovative Mode of Proactive Surveillance on Infectious Disease.

Surveillance is a critical component of epidemiological and public health practice, playing a significant role in the prevention, control, and management of major public health risks (1). Historically, surveillance methods were primarily based on hospital data (e.g., sentinel hospital monitoring for influenza) or specific populations [such as the human immunodeficiency virus/acquired immunodeficiency syndrome (HIV/AIDS) population] for sentinel surveillance. However, for newly emerging infectious diseases or major infectious diseases with pandemic potential, traditional methods based on hospitals or specific populations may be insufficient for meeting the requirements of multi-source information, active monitoring, and early warning. For instance, the reported number of coronavirus disease 2019 (COVID-19) cases represents passive reporting data, as there is a certain proportion of asymptomatic infected individuals and those who have not been tested. As most countries have relaxed or eliminated COVID-19 testing strategies, the number of reported cases may not accurately or comprehensively reflect the global prevalence levels and dynamic trends of COVID-19 in the general population. Following the early outbreak phase of COVID-19, China entered a normalization stage of prevention and control on April 29, 2020. During this stage, by adopting a strategy to prevent both imported cases and domestic resurgences, China effectively controlled the epidemic’s spread and significantly reduced the number of deaths. On December 7, 2022, China implemented the “Ten New Measures” to optimize COVID-19 prevention and control efforts further. Against this backdrop, China quickly and urgently established the nationwide Sentinel Community-Based Surveillance (SCS) by the end of 2022 (2), an innovative method for actively detecting infectious diseases, which aims to dynamically monitor the incidence rate of COVID-19 within the general population and provide an evidence-based foundation for estimating healthcare resource needs and allocating resources scientifically. SCS has played an essential, necessary, and irreplaceable role in actively tracking the COVID-19 epidemic situation and effectively managing public health risks in the general population in China. This study analyzes and describes the definition, characteristics of community-based surveillance, and practical experiences in China, providing a model reference for proactive surveillance in other countries or for other infectious diseases.