title: Interim report on the A/H1N1 influenza virus pandemic in Marseille, France, April-November 2009.
abstract: We report here the results of a 7-month survey of the influenza A/H1N1 pandemic in the Virology laboratory of the public hospitals of Marseille (April-November 2009). In total, 8 587 samples were analysed during this period, of which 1 974 (23%) were positive for the novel influenza variant. The analysis of results obtained using rapid influenza diagnostic tests (RIDTs) revealed a global sensitivity of 49.4% (vs. molecular qRT-PCR detection), strongly correlated with age groups (varying from 30% to 58% for patients >40 age and <10, respectively), indicating that RIDTs can be helpful in accelerating the management of suspected cases. Epidemiological analysis showed that the winter influenza wave began in October in Marseille (i.e. 2 to 3 months earlier than usual seasonal influenza outbreaks) and that the majority of autochthonous cases were observed in patients younger than 20 years old, with a low number of cases in patients over 60 years old. In November 2009, 22.2% (167/754) of patients with a laboratory diagnosis of influenza A/H1N1 infection were hospitalized, of which 9% (15/167) were admitted to an intensive care unit (ICU). Patients in the extreme age groups (>40 years old and <1) were significantly more often hospitalized than others, and 2.4% of hospitalized patients died. During the last 3 weeks of the period, the average number of bed-days attributable to H1N1sw-positive patients was 31.4, of which 5.9 were in ICUs.
authors.affiliation: Unité des Virus Emergents, UMR190, Université de la Méditerranée et Institut de Recherche pour le Développement, Marseille.
authors.forename: A
authors.initials: A
authors.lastname: Nougairede
authors.forename: L
authors.initials: L
authors.lastname: Ninove
authors.forename: C
authors.initials: C
authors.lastname: Zandotti
authors.forename: S-D
authors.initials: SD
authors.lastname: Thiberville
authors.forename: C
authors.initials: C
authors.lastname: Gazin
authors.forename: B
authors.initials: B
authors.lastname: La Scola
authors.forename: R N
authors.initials: RN
authors.lastname: Charrel
authors.forename: X
authors.initials: X
authors.lastname: de Lamballerie
mesh_terms: D000293:Adolescent; D000328:Adult; D002648:Child; D004196:Disease Outbreaks; D005602:France; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000175:diagnosis / Q000453:epidemiology*; D008875:Middle Aged; D018571:Sentinel Surveillance