Compared to an unadjuvanted vaccine, an adjuvanted influenza vaccine can reduce by almost a quarter the risk of hospitalization for respiratory illness (e.g. influenza and pneumonia) in elderly recipients. Thus the invention provides a method for immunizing an elderly subject by administering an adjuvanted influenza vaccine, whereby the subjects risk of hospitalization for respiratory illness (e.g. influenza and pneumonia) is reduced relative to an elderly subject who receives an unadjuvanted influenza vaccine.
