Lessons from the epidemiological surveillance program, during the influenza A (H1N1) virus epidemic, in a reference university hospital of Southeastern Brazil

• Published in: Revista da Sociedade Brasileira de Medicina Tropical
• Main Authors: Maria Luiza Moretti, Verônica Sinkoc, Luis Gustavo de Oliveira Cardoso, Gema Jesus de Camargo, Luis Felipe Bachur, Christian Cruz Hofling, Rodrigo Angerami, Plínio Trabasso, Márcia Teixeira Garcia, Mariângela Ribeiro Resende
• Format: Article in Journal/Newspaper
• Language: English
• Published: Sociedade Brasileira de Medicina Tropical (SBMT) 2011
• Subjects: Influenza sazonal; Influenza A H1N1; Vigilância epidemiológica; Síndrome gripal; Síndrome respiratória aguda; Arctic medicine. Tropical medicine; RC955-962; Arctic; Aguda
• Online Access: https://doi.org/10.1590/s0037-86822011005000048; https://doaj.org/article/0dec63fe20824b4b9eeee7b2fddcfe3f

INTRODUCTION: The case definition of influenza-like illness (ILI) is a powerful epidemiological tool during influenza epidemics. METHODS: A prospective cohort study was conducted to evaluate the impact of two definitions used as epidemiological tools, in adults and children, during the influenza A H1N1 epidemic. Patients were included if they had upper respiratory samples tested for influenza by real-time reverse transcriptase polymerase chain reaction during two periods, using the ILI definition (coughing + temperature > 38ºC) in period 1, and the definition of severe acute respiratory infection (ARS) (coughing + temperature > 38ºC and dyspnoea) in period 2. RESULTS: The study included 366 adults and 147 children, covering 243 cases of ILI and 270 cases of ARS. Laboratory confirmed cases of influenza were higher in adults (50%) than in children (21.6%) ( p < 0.0001) and influenza infection was more prevalent in the ILI definition (53%) than ARS (24.4%) (p < 0.0001). Adults reported more chills and myalgia than children (p = 0.0001). Oseltamivir was administered in 58% and 46% of adults and children with influenza A H1N1, respectively. The influenza A H1N1 case fatality rate was 7% in adults and 8.3% in children. The mean time from onset of illness until antiviral administration was 4 days. CONCLUSIONS: The modification of ILI to ARS definition resulted in less accuracy in influenza diagnosis and did not improve the appropriate time and use of antiviral medication.