Descriptive study of severe hospitalized cases of laboratory-confirmed influenza during five epidemic seasons (2010–2015)

Abstract

Objective: The Plan of Information on Acute Respiratory Infections in Catalonia (PIDIRAC) included the surveillance of severe hospitalized cases of laboratory-confrmed infuenza (SHCLCI) in 2009. The objective of this study was to determine the clinical, epidemiological and virological features of SHCLCI recorded in 12 sentinel hospitals during fve infuenza seasons. Results: From a sample of SHCLCI recorded during the 5 infuenza epidemics seasons from 2010–2011 to 2014–2015, Cases were confrmed by PCR and/or viral isolation in cell cultures from respiratory samples. A total of 1400 SHCLCI were recorded, 33% required ICU admission and 12% died. The median age of cases was 61 years (range 0–101 years); 70.5% were unvaccinated; 80.4% received antiviral treatment (in 79.6 and 24% of cases within 48 h after hospital admission and the onset of symptoms, respectively); infuenza virus A [37.9% A (H1N1)pdm09, 29.3% A (H3N2)] was identifed in 87.7% of cases. Surveillance of SHCLCI provides an estimate of the severity of seasonal infuenza epidemics and the identifcation and characterization of at-risk groups in order to facilitate preventive measures such as vaccination and early antiviral treatment.