Presentation

A presentation in many language             

A collaboration between general practionners, pediatricians and researchers

The French Sentinelles network is a research and health monitoring network for primary care (general medicine and pediatrics) in mainland France.

Created in 1984, it is coordinated by the “Surveillance and modelling of communicable diseases” (SUMO) team at the Institut Pierre Louis d'Epidémiologie et de Santé Publique (Iplesp). Iplesp is a joint health research unit (UMR-S 1136, formerly UMR-S 707, 444 and 263) under the joint supervision of the  French National Institute of Health and Medical Research (Inserm) and Sorbonne University. The Sentinelles network is developed in collaboration with the national public health agency (Santé publique France). It has obtained a research autorisation from the french independent administrative authority protecting privacy and personal data (CNIL).

The main objectives of the Sentinelles network are :

• to build up large databases in general medicine and pediatrics, for health monitoring and research purposes;
• the development of epidemic detection and forecasting tools;
• set up clinical and epidemiological studies.

On January 1, 2024, the Sentinelles network comprised 1,135 volunteer private general practitioners (2% of private general practitioners in mainland France) and 127 volunteer private pediatricians (4.8% of private pediatricians in mainland France) throughout mainland France. Member doctors are known as “Sentinelle doctors”.

This national surveillance system collects, analyzes, forecasts and redistributes epidemiological data in real time, based on the activities of independent general practitioners and pediatricians. The Sentinelles network continuously collects information on various health indicators. The computer system has been developed to be flexible and capable of easily adding or deleting new surveillance data as the situation in France evolves.

Every week, Sentinelles GPs transmit the data of their patients seen in consultation for the indicators monitored via a secure Internet connection, which complies with current French requirements on the confidentiality of information systems. From these data, it is possible to estimate the weekly incidence rate for each indicator, and to track its evolution over time and space. To estimate the national weekly or annual incidence rate, the average number of cases seen per Sentinelles GP (normalized according to their participation and geographical distribution) is multiplied by the total number of GPs in France, and the result is then divided by the French population to obtain an incidence rate (more methodological details, in French).

Since September 2014, the Sentinelles network, in collaboration with the national public health agency (Santé publique France), and the national center of reference (CNR) for respiratory viruses (including influenza), has been in charge of national coordination of virological surveillance of cases of acute respiratory infection seen in primary care consultations (in general medicine and outpatient pediatrics). The main aim of this surveillance program is to identify circulating viruses and strains of five respiratory viruses (Sars-Cov-2, influenza viruses, respiratory syncytial virus (RSV), rhinovirus and metapneumovirus).

Epidemiological data in real time

Feedback is organized as a platform for querying data at any time. The interface is user-friendly, so that any user can explore the database. It is possible to download maps, time series or tables on the selected health indicator. The database is updated weekly and contains the entire series without any interruption in time or space. The site receives over 200,000 visits per month. The French media (newspapers, radio, TV channels, Internet) download maps during epidemic periods for influenza, covid-19, RVS, gastroenteritis and chickenpox. All users have unrestricted access to the data. To help users interpret the data, the network publishes a weekly epidemiological bulletin in French and English, called Sentiweb-Hebdo, posted on the Sentinelles website and sent to over 11,000 subscribers. An annual report is published in French on the website, with a full analysis of the health indicators monitored.

Sentinelles physicians have contributed epidemiological data on selected communicable disease in France since 1984. These data have enabled national and international collaborations on epidemiologic evaluations and research; below are some examples:

• Modeling infectious diseases to predict the effect of proposed interventions and to assist in decision making: By reproducing a theoretical distribution of infection and its consequences, it is possible to estimate the basic parameters of the transmission, to assess a priori the medical, economic and social impact of control strategies and interventions, and to identify information needed to be collected.

• Detection of epidemics of influenza and gastroenteritis. The detection of outbreaks of influenza-like illness and acute diarrhea is made by a periodic regression model applied to the historical incidence rates series. It achieves an epidemic threshold for the current week of calculation. By comparing the incidence rate observed and the epidemic threshold, we can determine if an outbreak has begun.

• Epidemic forecasting. The French Sentinelles network uses two epidemic prediction models:

  • Model based on historical incidence rate: This method, derived from a model used in meteorology, has been adapted by Viboud et al to forecast epidemic trends. This method uses vectors selected from historical ILI time series that match current activity. Looking at the incidence rate that followed selected historical sequences, we can predict the incidence rates that will follow in the next three weeks.

  • Model based on drug sales: In addition to physician data, the Sentinelles network receives weekly data on sales of drugs provided by IMS Health, France. Research by Vergu et al. showed a high correlation between sales of certain classes of drugs and the ILI incidence, with a time lag: the increase in drug sales occurs before the increase of ILI incidence rate. A Poisson regression model predicts the ILI incidence rate at week t +1, t +2 and t +3 using sales of drugs at week t and ILI incidence rate at week t.

• Assessment of the field effectiveness of influenza vaccine. Since 1995, the field vaccine effectiveness (FVE) of influenza vaccines is monitored inside this surveillance system using the screening method. The screening method compares the vaccine coverage of ILI cases with the coverage in the population from where the cases are drawn. The vaccine coverage of ILI cases is usually estimated based on ILI cases reported by Sentinelles GPs ?vaccination status is reported with each ILI case. Data on vaccine coverage in the population are obtained, at no cost to the program, from an external source (observational study). Then they can easily be integrated to the surveillance system and used for quick estimates of FVE. Thus, the process can be reproduced each year, allowing for year-to-year comparison.

• Website for the detection and measurement of epidemics. A freely accessible analysis tool has been provided online to facilitate the processing of epidemiological time series data (Periodic). The tool can detect outbreaks in a series of observations, measure the magnitude, or establish an epidemic threshold for prospective surveillance. It is the result of a synthesis of periodic regression models. A generic method to construct periodic regression models has been developed. A user-friendly Web-tool is provided to facilitate analysis by non-statisticians. 

The French Sentinelles network is regularly involved in epidemiological studies. Study results are posted as final reports on the website of the Sentinelles network, presented in international conferences, and published (specific section in french).