Fig. 1.

Disposition and influenza positivity of included patients. Community-dwelling patients residing in predefined catchment areas of the participating hospitals and hospitalized < 48 h with presenting complaints potentially associated with influenza were eligible. Patients aged > 5 years had to have ≥1 systemic symptom (fever/feverishness, malaise, headache, or myalgia) and ≥ 1 respiratory symptom (cough, sore throat, or shortness of breath) and had to have been hospitalized < 7 days of the onset of the symptoms. Patients aged ≤5 years had to be hospitalized < 7 days after the appearance of symptoms potentially associated with influenza. Patients were excluded if they had been discharged from a hospital < 30 days before the current episode. Influenza infection was confirmed and typed/subtyped by RT-PCR