title: Human infection with pandemic A (H1N1) 2009 influenza virus: clinical observations in hospitalized patients, Americas, July 2009 - update.
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D002170:Canada / Q000453:epidemiology; D002677:Chile / Q000453:epidemiology; D015897:Comorbidity; D005260:Female; D006760:Hospitalization / Q000706:statistics & numerical data*; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype; D007251:Influenza, Human / Q000150:complications / Q000453:epidemiology*; D008297:Male; D008800:Mexico / Q000453:epidemiology; D008875:Middle Aged; D011024:Pneumonia, Viral / Q000150:complications / Q000453:epidemiology; D014481:United States / Q000453:epidemiology; D055815:Young Adult