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International audience; BACKGROUND: Epidemiological analysis of past influenza epidemics remains essential to understand the evolution of the disease and optimize control and prevention strategies. Here, we aimed to use data collected by a primary care surveillance system over the last three decades to study trends in influenza epidemics and describe epidemic profiles according to circulating influenza viruses.METHODS: Influenza-like illness (ILI) weekly incidences were estimated using cases reported by general practitioners participating in the French Sentinelles network, between 1984 and 2017. Influenza epidemics were detected by applying a periodic regression to this time series. Epidemic (co-)dominant influenza virus (sub)types were determined using French virology data.RESULTS: During the study period, 297 607 ILI cases were reported allowing the detection of 33 influenza epidemics. On average, seasonal epidemics lasted 9 weeks and affected 4.1% of the population (95% CI 3.5; 4.7). Mean age of cases was 29 years. Epidemic size decreased over time by -66 cases per 100 000 population per season on average (95% CI -132; -0.2, P value = 0.049) and epidemic height decreased by -15 cases per 100 000 (95% CI -28; -2, P value = 0.022). Epidemic duration appeared stable over time. Epidemics were mostly dominated by A(H3N2) (n = 17, 52%), associated with larger epidemic size, higher epidemic peak and older age of cases.CONCLUSIONS: The declining trend in influenza epidemic size and height over the last 33 years might be related to several factors like increased vaccine coverage, hygiene improvements or changing in influenza viruses. However, further researches are needed to assess the impact of potential contributing factors to adapt influenza plans.

International audience; This article summarizes the influenza activity in France for the 2016-17 season.Methods – This report is based on the descriptive analysis of different sources of data on influenza or influenza- like illness collected in mainland France: influenza clinical activity in the community reported by the primary health care network, virological data analysed by reference laboratories, emergency units visits and hospitali- zations for clinical influenza, reporting of acute respiratory infections (ARI) clusters in nursing homes, reporting of severe influenza cases hospitalised in intensive care units (ICU) and mortality data.Results – In mainland France, the 2016-17 season was characterized by a moderate influenza epidemic in the community which started in mid-December, peaked mid-January and lasted 10 weeks. Sub-type A(H3N2) viruses were the almost exclusive circulating influenza viruses. The impact of the influenza epidemic was espe- cially severe among the elderly (65 years old and more) with a high proportion of hospitalisations for influenza among outpatients presenting to emergency ward (16% of 40 000 outpatients) and a high proportion of patients aged above 65 years (69%) among hospitalized patients. This age group accounted for 67% of the 1,479 cases admitted to intensive care. During the epidemic wave, a marked excess mortality estimate at 14,400 deaths attributable to influenza was observed. Over 90% of this excess affected people 75 years old and more.Conclusion – The 2016-17 influenza epidemic was early, moderate, and particularly severe among the elderly. This severity is due to the almost exclusive circulation of A(H3N2) viruses in a context of low vaccine coverage and sub-optimal vaccine effectiveness. It confirms the severity of the disease for the population at risk and strengthens the need for prevention, especially a higher vaccine coverage among people at risk and the implementation of non-pharmaceutical control measures to limit the spread of the virus around cases.; Cet article présente le bilan épidémiologique et virologique de l’activité grippale en France durant la saison 2016-2017.Méthodes – Ce bilan s’appuie sur l’analyse descriptive des données de surveillance de la grippe ou des syndromes grippaux transmises par les réseaux de médecine ambulatoire, les analyses virologiques des laboratoires partenaires, les signalements d’épisodes d’infections respiratoires aiguës (IRA) dans les collec- tivités de personnes âgées, la surveillance des passages aux urgences et des hospitalisations codées grippe, la surveillance des cas graves de grippe hospitalisés en services de réanimation et les données de mortalité.Résultats – L’épidémie de grippe a débuté mi-décembre et a atteint son pic mi-janvier pour se terminer début février, soit une durée totale de 10 semaines. Due quasi-exclusivement au virus grippal de type A(H3N2), elle a été d’intensité modérée en milieu ambulatoire mais a eu un impact important chez les personnes âgées. Elle a été caractérisée par une part importante d’hospitalisations parmi les passages aux urgences pour syndrome grippal (16% des 40 000 passages) et par une proportion importante des 65 ans et plus parmi les patients hospitalisés (69%). Cette tranche d’âge a représenté 67% des 1 479 cas de grippe admis en réanimation. Cette épidémie a également été marquée par un excès de mortalité estimé à 14 400 décès attribuables à la grippe, dont plus de 90% chez les personnes de 75 ans et plus.Conclusion – L’épidémie de grippe 2016-2017, précoce et d’intensité modérée, s’est caractérisée par un impact particulièrement important chez les personnes âgées, lié à la circulation quasi-exclusive de virus A(H3N2) dans un contexte de couverture vaccinale insuffisante et d’efficacité vaccinale sub-optimale. Cette épidémie rappelle la gravité de la maladie et l’importance de la prévention, à savoir la vaccination chez les personnes à risque, qui doit être complétée de mesures barrières pour limiter la diffusion du virus dans l’entourage des cas.

International audience; PURPOSE: In-patients characteristics generate cost differences between hospitals. In France, there are few data on the characteristics on the patients referred to hospitals by their general practitioners (GPs) and none on the predictors of referral to the public or for-profit hospitals. The aim of this study was to analyze those characteristics and the predictors of referral to the public or for-profit hospitals. METHODS: We collected, prospectively, the request for hospitalizations made by the GPs of the Sentinelles network in France, from 2007 to 2009. Patients' characteristics and also the reasons for that request were analyzed. A logistic regression was used to compare the population between local hospitals. RESULTS: Ten thousand seven hundred and eighteen statements were collected. The median age was 73 years. Patients were women in 51% of the cases, and only 14% of the hospitalizations had been planned. Hospitalization in the public sector was preferred for young children and the elderly (P

International audience; BACKGROUND: The case-hospitalization ratio (CHR) is a key quantity for the management of emerging pathogens such as pandemic influenza. Yet, few running surveillance systems prospectively monitor the CHR during influenza epidemics. Here, we analyze the proportion of recommended hospitalizations (PRH) among influenza-like illness (ILI) patients attended in general practice in France and compare the PRH observed during the 2009-2010 A(H1N1) pandemic with the one of the twelve previous seasons. METHODS: ILI cases were recorded by general practitioners (GPs) involved in surveillance, who indicated for each case whether they recommended hospitalization. We stratify the analysis by age, sex, and viral subtype. We investigate the reasons why GPs recommended hospitalization and the presence of risk factors for pandemic A(H1N1) complications. RESULTS: The average PRH over the seasons 1997-1998 to 2008-2009 was 3*4‰ (3-3*9). It was three times higher during the 2009-2010 pandemic than during seasonal influenza epidemics (OR = 2*89, 95% CI: 2*28-3*64). The highest increase was among 20-39-year-old women: OR = 11*8 (5*04-29*59). Overall, the principal reasons for recommending hospitalization were "respiratory problems" and "bad general condition." However, during the pandemic, "age" (mainly associated with infants), "pregnancy," and "diagnostic" became more frequent than before (P < 0*001). Finally, pregnancy was the reported risk factor for pandemic A(H1N1) complications that had the largest impact on hospitalization recommendation during the pandemic (OR = 38*62, P < 0*001). CONCLUSION: Easily implemented in surveillance systems, this protocol has the potential to reveal changes in hospitalization recommendation by GPs. Moreover, if the right data are collected alongside, it could give timely insights into epidemic severity.