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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 influenza activity in France for the 2017-2018 season.Methods –This report is based on different sources of data collected in France: clinical influenza-like illness (ILI) in the community reported by the primary health care networks, virological data analysed by reference laboratories, emergency units visits and hospitalizations for clinical influenza, reporting of severe influenza cases hospitalised in intensive care units (ICU), reporting of acute respiratory infections (ARI) clusters in nursing homes, and mortality data.Results –In France, the 2017-18 season started early-December in mainland France, peaked on the last week of December and ended at the end of March, lasting 16 weeks. The epidemic was characterized by an atypical dynamics with two consecutive waves due to the circulation ofA(H1N1)pdm09 followed by B/Yamagata lineage viruses. Its impact was moderate in the community, but high numbers of hospitalizations (>9,700) and severe cases admitted to ICUs (>2,900) were recorded. During the epidemic, a marked excess mortality was observed, with 13,000 deaths attributed to influenza.Conclusion –The 2017-18 influenza epidemic started early and was unusually long, with an atypical dynamics and marked severity. The successive circulation of A(H1N1)pdm09 and B/Yamagata viruses, together with insufficient vaccine coverage and suboptimal vaccine effectiveness, have contributed to this severity. It confirms the high impact of the disease for the population at risk and strengthens the need for prevention especially higher vaccine coverage among people at risk, and the implementation of control measures to limit the spread of the virus around the cases, as well as the utility of early antiviral treatment for subjects at risk.; Cet article présente le bilan épidémiologique et virologique de l’épidémie grippale en France durant la saison 2017-2018.Méthode –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, la surveillance des passages aux urgences et des hospitalisations codées grippe, la surveillance des cas graves de grippe hospitalisés en services de réanimation, les signalements d’épisodes d’infections respiratoires aiguës (IRA) dans les collectivités de personnes âgées et les données de mortalité.Résultats –L’épidémie de grippe a débuté début décembre en France métropolitaine, a atteint son pic au cours de la dernière semaine de décembre et s’est terminée fin mars, soit 16 semaines d’épidémie. Elle a présenté une dynamique atypique, avec deux vagues successives dues à la circulation majoritaire du virus A(H1N1)pdm09 puis à celle du virus B Lignage Yamagata. L’épidémie a été d’intensité modérée en médecine ambulatoire mais elle a été caractérisée par un nombre élevé d’hospitalisations après recours aux urgences pour syndrome grippal (>9 700) et de cas graves admis en réanimation (>2 900). Cette épidémie a également été marquée par une surmortalité importante, avec 13 000 décès attribués à la grippe.Conclusion –L’épidémie de grippe 2017-2018, précoce et exceptionnellement longue, a été caractérisée par une dynamique atypique et une importante sévérité, liées à la circulation successive des virus A(H1N1)pdm09 et B/Yamagata, dans un contexte de couverture vaccinale insuffisante et d’efficacité vaccinale sous-optimale. Son impact important sur les hospitalisations et la mortalité rappelle la gravité de la maladie et l’intérêt de la prévention, à savoir la vaccination chez les personnes à risque, complétée de mesures barrières afin de limiter la diffusion du virus dans l’entourage des cas, ainsi que l’utilité d’un traitement antiviral précoce, particulièrement chez les sujets à risque.

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; Background: GP consultation rates for influenza-like illness (ILI) are poorly known in France and there is a paucity of literature on this topic. In the few articles that have been published, the results are heterogeneous.Aim: The aim of the present study was to estimate the proportion of ILI inducing a GP consultation, and to assess its determinants.Design & setting: Participants of a French web-based cohort study who reported ≥1 ILI episode between 2012 and 2015 were included. Sociodemographic characteristics, access to health care, and health status variables were collected.Method: Healthcare-seeking behaviour was analysed and factors associated with a GP consultation identified using a conditional logistic regression.Results: Of the 6023 ILI episodes reported, 1961 (32.6%) led to a GP consultation, with no difference between those at risk of influenza complications and those not (P = 0.42). A GP consultation was more frequent for individuals living in a rural area (odds ratio [OR] = 1.21, 95% confidence interval [CI] = 1.02 to 1.43); those with a lower educational level (OR = 1.43, 95% CI = 1.18 to 1.74); those using the internet to find information about influenza (OR = 1.63, 95% CI = 1.30 to 2.03); patients presenting with worrying symptoms (fever, cough, dyspnoea, sputum, or asthenia); patients having a negative perception of their own health status (OR = 1.51, 95% CI = 1.07 to 2.13; and those having declared a personal doctor (OR = 2.86, 95% CI = 1.72 to 4.76). A GP consultation was less frequent for individuals using alternative medicine (OR = 0.68, 95% CI = 0.58 to 0.78).Conclusion: This study allows the identification of specific factors associated with GP consultation for an ILI episode. These findings may help to coordinate health information campaigns and to raise awareness, especially among individuals at risk of influenza complications.

International audience; BACKGROUND:In a context of controversy about influenza antiviral treatments, this study assessed primary health-care physicians' prescription of neuraminidase inhibitors (NIs) in France during pandemic and seasonal influenza between 2009 and 2013.METHODS:This observational study, using data recorded in three national databases, estimated the rate of NI prescription among influenza-like illness (ILI) patients seen in GP and paediatrician consultations, and determined factors associated with this prescription according to a multivariate analysis. NI delivery by pharmacists was also evaluated.RESULTS:Rates of NI prescription were estimated to be 61.1% among ILI patients with a severe influenza risk factor seen in GP consultation during the A(H1N1)pdm2009 pandemic versus an average rate of 25.9% during the three following seasonal influenza epidemics. Factors associated with NI prescription were a chronic disease in patients under 65 years (OR 14.85; 95% CI 13.00, 16.97) and in those aged 65 and older (OR 7.54; 5.86, 9.70), an age ≥65 years in patients without chronic disease (OR 1.35; 1.04, 1.74), a pregnancy (OR 10.63; 7.67, 15.76), obesity (OR 4.67; 3.50, 6.22) and a consultation during the pandemic A(H1N1)pdm2009 (OR 3.19; 2.93, 3.48). The number of antiviral treatments delivered by pharmacists during the A(H1N1)pdm2009 pandemic was 835 per 100,000 inhabitants, and an average of 275 per 100,000 inhabitants during the three following seasonal influenza epidemics.CONCLUSIONS:Although physicians seem to follow the recommended indications for NIs in primary health-care practice, this study confirms the low rate of NI prescription to ILI patients with a severe influenza risk factor, especially during seasonal epidemics.