First wave of the influenza A/H1N1v pandemic in Switzerland - Nickel, C. H.; Stephan, F. P.; Dangel, M.; Blume, K.; Gehrisch, R.; Dumoulin, A.; Tschudin, S.; Keller, D. I.; Hirsch, H. H.; Widmer, A. F.; Bingisser, R. (Swiss Med Wkly, 2009)
AIM: To describe the disease burden, clinical pattern and outcome of influenza-related cases presenting to a Swiss Emergency Department (ED), during the first wave of the 2009 pandemic. METHODS: Retrospective analysis of prospectively collected data at the University Hospital of Basel, Switzerland. All patients presenting to the ED with influenza-like symptoms from June 1 to October 23, 2009, were studied. Rate of hospitalisation, demographic characteristics, symptoms, microbiological diagnoses and complications of influenza infection were analysed. RESULTS: One tenth (808 of 8356 patients) of all non-trauma ED presentations, during the study period, were a result of suspected influenza-related illness. Influenza A/H1N1v infection accounted for 5% of these presentations. Patients aged 50 years or less accounted for 87% of these presentations and for 100% of A/H1N1v infection. The highest detection rate of A/H1N1v-infection occurred in July, and the highest rate of clinical presentations occurred in August 2009. Underlying medical disease was observed in 14% of all patients. The presence of fever, cough and myalgia was the prime clinical predictor for the presence of A/H1N1v infection. 16% of patients with this triad suffered from A/H1N1v. CONCLUSION: Suspected A/H1N1v infection contributed to a considerable health care burden in Switzerland. However, the rate of true positivity was low (5%), hospitalisations rare (5%), and mortality did not occur. Therefore, the first wave of the A/H1N1v pandemic in Switzerland was rather media "hype" than real threat.
Keywords: journalArticle; *Population Surveillance; Adult; Comorbidity; Disease Outbreaks; Female; Humans; Influenza A Virus, H1N1 Subtype/*genetics/isolation & purification; Influenza, Human/*epidemiology/virology; Male; Oseltamivir; Polymerase Chain Reaction; Prospective Studies; Retrospective Studies; Switzerland/epidemiology; Young Adult