Analysis of acute respiratory infections due to influenza virus A, B and RSV during an influenza epidemic 2018

PurposeWe studied the incidence, morbidity and mortality of all patients presenting in our teaching hospital with proven influenza virus and/or respiratory syncytial virus (RSV) infection during the influenza epidemic season 2018 which was characterized by a predominant incidence of influenza virus B type B of the Yamagata line.MethodsIn the fall of 2017, specific precaution measures in addition to standard measures were implemented, including standardized testing for influenza virus A,B and RSV by multiplex PCR of pharyngeal swabsData from all consecutive patients were analyzed retrospectively.ResultsOverall 651 patients were examined for the presence of influenza virus and RSV; 214 patients had influenza virus A (n=36), B (n=152), and/or RSV (n=30), including four patients with dual infection. 86% of cases had influenza virus (80% B), and 14% RSV infection. N=23 cases were treated as outpatients. The rate of acute viral respiratory infections (influenza virus and RSV) was 191 of 2776 (6.9%) admissions to medical wards. Of n=191 hospitalized cases, n=44 cases (20.6%) had nosocomial infection. Viral infections were associated with a high morbidity (pneumonia 28.5%, mortality 4.7%). Independent predictors of prolonged hospitalization were the presence of pneumonia, NIV and renal complications, and independent predictors of pneumonia were age65 years, bedridden status and CRP2.9mg/dL.ConclusionsThe rate of nosocomial cases was high despite established precaution measures. RSV was associated with morbidity and mortality comparable to influenza. Pneumonia remains the main complication of acute viral respiratory infections, and antimicrobial treatment should include both antiviral as well as antibacterial agents.