title: Seroepidemiological study of pandemic influenza H1N1 following the 2009-2010 wave in Greece.
abstract: Knowledge of seroprevalence rates against 2009 pandemic H1N1 virus will assist vaccination recommendations and the preparation of the health-care system during subsequent years. This study was conducted in Greece during June-August 2010 to estimate the seroprevalence rate against pandemic H1N1 virus. Persons presenting in 29 health-care facilities across the country were studied. Seroprevalence was estimated employing a virus-free ELISA that specifically recognizes 2009 H1N1 virus antibodies in human sera. Sera collected from 2005 to April 2009 were also used to estimate pre-pandemic seroprevalence rates. A total of 954 persons were studied. The overall seroprevalence rate was 28.5% (95% confidence interval=25.6-31.3%). Age-specific rates were 34.2% in persons 0-4 years, 36.3% in persons 5-19 years, 25.0% in persons 20-39 years, 23.4% in persons 40-59 years, and 31.8% in persons ≥ 60 years. The highest rates were recorded in the Regions of Ionian Islands (67%) and Epirus (42.9%), while the lowest (8.4%) in the Region of Thessaly. Age-specific attack rates of infection during 2009-2010 were 28.8% in persons 0-4 years, 32.5% in persons 5-19 years, 14.3% in persons 20-39 years, 19.1% in persons 40-59 years, and 14.4% in persons ≥ 60 years. Multivariate analysis revealed that Region of residence and caring for children <5 years were associated with increased risk for seropositivity. Urbanity, personal and family characteristics, working in a health-care facility or in a school, history of pandemic H1N1 vaccination or history of influenza-like illness during 2009-2010 were not associated with increased risk for seropositivity.
authors.affiliation: Department for Interventions in Health-Care Facilities, Hellenic Center for Diseases, Control and Prevention, 3-5 Agrafon Street, Athens 15123, Greece. helen-maltezou@ath.forthnet.gr
authors.forename: Helena C
authors.initials: HC
authors.lastname: Maltezou
authors.forename: Panagiotis
authors.initials: P
authors.lastname: Katerelos
authors.forename: Maria
authors.initials: M
authors.lastname: Mavrouli
authors.forename: Athanasia
authors.initials: A
authors.lastname: Lourida
authors.forename: John G
authors.initials: JG
authors.lastname: Routsias
authors.forename: Nicholas
authors.initials: N
authors.lastname: Spanakis
authors.forename: Antonios
authors.initials: A
authors.lastname: Maragos
authors.forename: Anastasia
authors.initials: A
authors.lastname: Tedoma
authors.forename: Yiannis
authors.initials: Y
authors.lastname: Bassiakos
authors.forename: Georgios
authors.initials: G
authors.lastname: Koratzanis
authors.forename: Stephanos
authors.initials: S
authors.lastname: Mantagos
authors.forename: Simeon
authors.initials: S
authors.lastname: Metallidis
authors.forename: Aspasia
authors.initials: A
authors.lastname: Katragkou
authors.forename: Pavlos
authors.initials: P
authors.lastname: Nikolaidis
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Roilides
authors.forename: Maria
authors.initials: M
authors.lastname: Theodoridou
authors.forename: Athanassios
authors.initials: A
authors.lastname: Tsakris
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D000368:Aged; D000369:Aged, 80 and over; D000914:Antibodies, Viral / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005843:Geography; D006115:Greece / Q000453:epidemiology; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology*; D007251:Influenza, Human / Q000453:epidemiology* / Q000821:virology*; D008297:Male; D008875:Middle Aged; D016036:Seroepidemiologic Studies; D055815:Young Adult
chemical_list: D000914:Antibodies, Viral