Achievable influenza immunization rates in the elderly.

We sought to determine achievable rates of influenza immunization in a large internal medicine practice in which free vaccination was vigorously promoted. A list of 1,230 patients over 65 years of age constituted the target population. Seven hundred ninety patients (64%) were immunized in the office from September to December 1989. In early 1990, questionnaires were sent to 67 patients who had refused vaccination and to an equal number of age- and sex-matched controls who had either accepted the vaccine or whose immunization status was unknown. Seventy-four percent returned the questionnaires. Of the 67 unimmunized patients, 39 (53%) reported that they might be persuaded to accept immunization, whereas 22 (33%) said that nothing could convince them to be immunized. When we added persons who might accept influenza vaccine and persons who had received the vaccine in public clinics to the total number of patients immunized in the office setting, we reached a total of 1,059 patients (86.1% of the total), which we would propose as the maximal achievable immunization rate in this setting.