Figure 1

Study flow-chart. * Routine laboratory tests included white-cell count and chemical analysis (see text). ** Further investigations included H1N1 test, arterial blood analysis and electrocardiogram; in admitted patients diagnostic specimens from lower respiratory tract and blood cultures were recorded; CT scan and repeated chest radiography, if indicated, were also performed. ILI=influenza like illness; SARI=severe acute respiratory illness; CAP=community-acquired pneumonia; CRx=chest radiography; CT=computed tomography; US=ultrasonography.