[Clinical features of adults younger and older than 50 years hospitalized with influenza A H1N1 2009 in a private hospital in Santiago, Chile].

INTRODUCTION The new pandemic influenza A H1N1 2009 virus has shown a different clinical behavior in different age groups. OBJECTIVE To describe the clinical features of adult patients hospitalized with influenza AH1N1 2009 and compare the clinical and demographic variables among adults < 50 years and over 50 years old. PATIENTS AND METHOD We included hospitalized patients between May 17 and July 17, 2009 confirmed by polymerase chain reaction (PCR) and/or rapid test for influenza A. RESULTS 124 patients were hospitalized with a median age of 33 years (range: 15-82 years). 36% had comorbidities and the main symptoms were fever, cough, myalgia and sore throat. There were 16 cases with pneumonia. From 124 patients, 77% were < 50 and 23% > or = 50, [corrected] with comorbidity of 21% and 86%, respectively. There were no fatalities. CONCLUSIONS Hospitalized patients had mild to moderate disease, a benign course and short hospitalization stay. There were more hospitalizations in A-49 and higher comorbidity in A-50.