Achieving compliance with influenza immunization of medical house staff and students. A randomized controlled trial

To determine the optimal method to increase influenza immunization rates of medical house staff and students.

Prospective randomized trial and cross-sectional survey.

Four hundred forty-two internal medicine, obstetrics-gynecology, and general surgery residents and junior medical students.

The four interventions employed were (1) an educational memorandum outlining vaccine indications sent to all study group members, (2) a personal letter mailed to a random sample of half of the remaining unimmunized persons, (3) a telephone call to half of the unimmunized letter recipients, and (4) vaccine offered directly to the remaining unimmunized persons in clinics and conferences. In addition, a questionnaire was administered to all persons requesting or offered vaccine.

During the 3 weeks after the memorandum, 87 (20%) of 442 persons were immunized. Five weeks after the letter, 61 (34%) of persons receiving a letter and 30 (17%) of the no-letter controls (P = .0005) had been immunized. After the telephone call, there was a statistically insignificant trend toward increased compliance. In clinics and conferences, 90% of persons reached were immunized and 10% refused, largely extinguishing the effect of prior interventions. At completion of the study, 275 (62%) of 442 participants were immunized, 29 (7%) refused, and 138 (31%) were not reached. Questionnaire results revealed that only 32% had ever been previously immunized against influenza, yet 70% stated that they had worked despite having influenzalike symptoms.

A high rate of immunization of house staff and medical students can be achieved most effectively by offering vaccine in clinics and conferences. Continued education about influenza immunization is necessary for physicians and medical students.