Gallien Yves, Paireau Juliette, Paty Annie-Claude, Villegas-Ramirez Berenice, Hamidouche Mohamed, Modenesi Gabriela, Zhu-Soubise Aurélien, Bonaldi Christophe, Fouillet Anne, Vaux Sophie, Bernard-Stoecklin Sibylle, Tarantola Arnaud
Santé publique France Île-de-France, Saint-Denis, France.
Mathematical Modelling of Infectious Diseases Unit, Institut Pasteur, Université Paris Cité, Paris, France.
Am J Epidemiol. 2025 May 7;194(5):1332-1340. doi: 10.1093/aje/kwae195.
Yearly bronchiolitis and influenza-like illness epidemics in France often involve high morbidity and mortality, which severely impact health care. Epidemics are declared by the French National Institute of Public Health based on syndromic surveillance of primary care and emergency departments (EDs), using statistics-based alarms. Although the effective reproduction number (Rt) is used to monitor the dynamics of epidemics, it has never been used as an early-warning tool for bronchiolitis or influenza-like illness epidemics in France. We assessed whether Rt is useful for detecting seasonal epidemics by comparing it to the tool currently used (MASS) by epidemiologists to declare epidemic phases. We used anonymized ED syndromic data from the Île-de-France region in France from 2010 to 2022. We estimated Rt and compared the indication of accelerated transmission (Rt > 1) to the MASS epidemic alarm time points. We computed the difference between those 2 time points, time to epidemic peak, and the daily cases documented at first indication and peak. Rt provided alarms for influenza-like illness and bronchiolitis epidemics that were, respectively, a median of 6 days (IQR, 4, 8) and 64 days (IQR, 52, 80) earlier than the alarms provided by MASS. Rt detected earlier signals of bronchiolitis and influenza-like illness epidemics. Using this early-warning indicator in combination with others to declare an annual epidemic could provide opportunities to improve health care system readiness.
在法国，每年的细支气管炎和流感样疾病疫情常常导致高发病率和高死亡率，对医疗保健造成严重影响。法国国家公共卫生研究所根据对初级保健和急诊科的症状监测，并使用基于统计的警报来宣布疫情。尽管有效繁殖数（Rt）被用于监测疫情动态，但在法国它从未被用作细支气管炎或流感样疾病疫情的预警工具。我们通过将Rt与流行病学家目前用于宣布疫情阶段的工具（MASS）进行比较，评估了Rt对于检测季节性疫情是否有用。我们使用了2010年至2022年法国法兰西岛地区匿名的急诊科症状数据。我们估计了Rt，并将加速传播的指标（Rt > 1）与MASS疫情警报时间点进行比较。我们计算了这两个时间点之间的差异、到达疫情高峰的时间以及首次出现症状和高峰时记录的每日病例数。Rt为流感样疾病和细支气管炎疫情发出的警报分别比MASS发出的警报提前了中位数6天（四分位间距，4，8）和64天（四分位间距，52，80）。Rt更早地检测到了细支气管炎和流感样疾病疫情的信号。将这一预警指标与其他指标结合使用来宣布年度疫情，可能会为提高医疗保健系统的应对能力提供机会。
