Human patients with influenza virus and bacterial infections

Peripheral blood was collected from human patients infected with influenza A virus only or in addition with bacterial pathogens and at different days after hospital admission. For comparison, blood from healthy controls was collected. Gene expression differences were detected in influenza and bacterial infections compared to healthy controls, and at various days post infection. We recruited patients from 20 hospitals during the period 2009 to 2016. The eligibility criteria included (1) age greater than 18 years and (2) World Health Organization definition of influenza-like illness (fever of 38 C° or higher, cough and illness onset within the last ten days). Eligible patients were assessed by an admitting physician for likelihood of influenza infection. Patients with a high likelihood of infection, based on history and clinical features, were enrolled into the study. Collection of peripheral blood from human patients, preparation of RNA and gene expression analysis using microarrays was performed.