Influenza and respiratory failure.
D000367:Age Factors; D000368:Aged; D002908:Chronic Disease; D006801:Humans; D007251:Influenza, Human / Q000150:complications*; D008875:Middle Aged; D012121:Respiration, Artificial; D012131:Respiratory Insufficiency / Q000150:complications* / Q000209:etiology / Q000628:therapy