Abstract
INTRODUCTION: Since 2009, influenza A H1N1pdm09 coexists with seasonal influenza (H3N2). The aim of this study was to describe the severity differences between both.
METHODS: A retrospective study from January to March 2014 in Hospital Miguel Servet, Zaragoza, Spain. We studied hospitalized adults with influenza A, and compared radiologic, clinical manifestations and outcomes. Multivariable analysis was performed for severity, defined as the presence of bilateral or multilobar pneumonia, septic shock, intensive care unit (ICU) admission, acute respiratory distress syndrome (ARDS) and intrahospitalary mortality.
RESULTS: Out of 234 patients, 146 had A-H1N1 and 88 A-H3N2, and everyone received Oseltamivir within 24 h from admittance. The median age was 64 years old in H1N1 and 77 in H3N2 (P<0.001). In H1N1 group, 45.2% presented pneumonia, 4.8% ARDS, 10.9% septic shock and 12.3% needed invasive ventilation vs H3N2 group (see Table 1). In our regression model, H1N1 influenza (OR: 2,525), no vaccination (OR: 3.086), and coinfection (viral and bacterial) (adjusted OR: 2.821) were independent risk factors for severe disease.
CONCLUSIONS: Patients infected with H1N1 Influenza A virus were younger and presented more severe disease than those with H3N2. H1N1 influenza A, lack of Influenza vaccination and coinfection were risk factors for increased seasonal influenza severity.
- Copyright ©the authors 2016
