title: Protection of trivalent inactivated influenza vaccine against hospitalizations among pandemic influenza A (H1N1) cases in Argentina.
abstract: The aim of this study was to estimate the effectiveness of 2009 seasonal trivalent inactivated vaccine in reducing hospitalizations due to the novel influenza A H1N1 virus among positive cases. Data collected from Argentina's national epidemiological surveillance system were analyzed. All patients had a clinical diagnosis and underwent positive serological tests for pandemic influenza A H1N1. Logistic regression was used to estimate vaccine effectiveness to prevent severe cases of the disease, measured as hospitalizations. The adjusted effectiveness of the vaccine was 50% (95% CI: 40-59%). Vaccination was significantly associated with hospitalizations in all age groups, and within groups that had and had not received antiviral treatment. These results suggest that seasonal influenza vaccine might have conferred partial protection against severe cases due to the novel pandemic influenza.
authors.affiliation: Departamento de Epidemiología, Ministerio de Salud de Tierra del Fuego, Leopoldo Lugones s/n Casa 8, Ushuaia, Tierra del Fuego 9410, Argentina. porellano@gmail.com
authors.forename: P W
authors.initials: PW
authors.lastname: Orellano
authors.forename: J I
authors.initials: JI
authors.lastname: Reynoso
authors.forename: O
authors.initials: O
authors.lastname: Carlino
authors.forename: O
authors.initials: O
authors.lastname: Uez
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D001118:Argentina / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004196:Disease Outbreaks / Q000517:prevention & control*; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000276:immunology; D007252:Influenza Vaccines / Q000008:administration & dosage*; D007251:Influenza, Human / Q000453:epidemiology / Q000517:prevention & control*; D016015:Logistic Models; D008297:Male; D008875:Middle Aged; D018571:Sentinel Surveillance; D015164:Vaccines, Inactivated / Q000008:administration & dosage; D055815:Young Adult
chemical_list: D007252:Influenza Vaccines; D015164:Vaccines, Inactivated