Portal de Periódicos da CAPES

Influenza Vaccine Effectiveness in Preventing Outpatient, Inpatient, and Severe Cases of Laboratory-Confirmed Influenza

2013; Oxford University Press; Volume: 57; Issue: 2 Linguagem: Inglês

10.1093/cid/cit194

1537-6591

Jesús Castilla, Pere Godoy, Fabiola Domínguez, Iván Martínez‐Baz, Jenaro Astray, Vicente Martín, Miguel Delgado‐Rodríguez, Maretva Baricot, Núria Soldevila, José María Mayoral, José M. Quintana, Juan Carlos Galán, Ady Castro, Fernando Gónzález‐Candelas, Olatz Garín, Marc Sáez, Sonia Tamames, Tomàs Pumarola, Ernestina Azor, Juan Sebastián Orozco Carrillo, Raquel Virginia Moyano, Juan A. Martín Navarro, Marco Alejandro Solórzano-Vázquez, Francisco Javier Ruiz Zafra, Maria Bautista, José María Navarro, I. Pedrosa, María José Pérez, Virtudes Gallardo, E. Pérez, José R. Maldonado, A. Morillo, M. C. Ubago, Demetrio Carriedo, Javier Moradiellos, Inmaculada Fernández, Stefan Fernandez, Javier Castrodeza, C. Rodríguez, P. Sanz, Raúl Ortíz de Lejarazu, A. Pérez, P. Redondo, A. Seco, Ángel Pérez Pueyo, José Luís Viejo, Tania Fernández, A. Molina, Ferrán Barbé, Lluís Blanch, Gemma Navarro, Xavier Bonfill, Joaquín López‐Contreras, Virginia Pomar, M. T. Puig, Eva Borras, Ana Martı́nez, Núria Torner, Francesc Calafell, Jordi Alonso, Joan A. Caylà, Cecilia Tortajada, I. Garc�a, José Domínguez, Juan José García‐García, Joaquim Gea, Juan Pablo Horcajada, Niamh Hayes, F.A. Moraga Llop, Jordi Dorca, Àlvar Agustí, Antoni Trilla, Antonia L. Vilella, Ricard Gènova, Marta Barquero, Eliza Gil, Sònia Jiménez, Fatima Martín‐Sánchez, M. L. Martínez, Sara Torrico Sánchez, Rafael Cantón, A. Robustillo, Christopher Jairo Rubio Álvarez, Alina Llop Hernández, Francisco Pozo, José Ramón Paño, Ana Martı́nez, Leonardo Martínez, Martín Ruiz Ortiz, P. Fanlo, F. García Gil, Víctor Martínez-Artola, M. E. Ursua, M. Sota, M. T. Virto, Jorge Gamboa, F. Pérez-Afonso, Urko Aguirre, A. Caspelastegui, Pedro Pablo España, S. García, Javier Arı́stegui, Amaia Bilbao, Adolfo Escobar, Itziar Astigarraga, J. M. Antoñana, Gustavo Cilla, Javier Korta, Emilio Pérez Trallero, J.L. Lobo, F. J. Troya, María Morales,

Pneumonia and Respiratory Infections

In most seasons, the influenza vaccine is effective in preventing influenza, but it is not clear whether it is equally effective in preventing mild and severe cases. We designed a case-control study to compare the effectiveness of the influenza vaccine in preventing outpatient, inpatient, and severe or fatal cases of laboratory-confirmed influenza.Hospitalized patients (n = 691) with laboratory-confirmed influenza in the 2010-2011 season recruited in 29 Spanish hospitals were individually matched by age, admission/visit date, and province with an outpatient with laboratory-confirmed influenza and an outpatient control. Severe cases were considered those patients admitted to intensive care units or who died in the hospital (n = 177). We compared the influenza vaccine status of controls and outpatient cases, inpatient cases, and severe cases using conditional logistic regression adjusted for potential confounding factors. Severe and nonsevere inpatient influenza cases were compared using unconditional logistic regression. Vaccine effectiveness was (1 - odds ratio) × 100.Vaccine effectiveness was 75% (adjusted odds ratio [AOR], 0.25; 95% confidence interval [CI], .16-.39) in preventing influenza outpatient cases, 60% (AOR, 0.40; 95% CI, .25-.63) in preventing influenza-associated hospitalizations, and 89% (AOR, 0.11; 95% CI, .04-.37) in preventing severe cases. In inpatients, influenza vaccination was associated with a lower risk of severe influenza (AOR, 0.42; 95% CI, .22-.80).Influenza vaccination prevented influenza cases and hospitalizations and was associated with a better prognosis in inpatients with influenza. The combined effect of these 2 mechanisms would explain the high effectiveness of the vaccine in preventing severe cases due to influenza.