Influenza vaccine in the elderly.
D000367:Age Factors; D000368:Aged; D002986:Clinical Trials as Topic; D005260:Female; D006801:Humans; D007252:Influenza Vaccines / Q000627:therapeutic use*; D007251:Influenza, Human / Q000517:prevention & control*; D008297:Male; D010919:Placebos; D006113:United Kingdom
D007252:Influenza Vaccines; D010919:Placebos