Vaccination of high-risk patients for influenza. A comparison of telephone and mail reminder methods

During the 1984-1985 influenza season two study groups were used to compare telephone and letter reminder methods with a control group that received no reminder to determine which was the most effective strategy to increase influenza vaccination rates among the high-risk patient population of a university-based family practice. Seven hundred eighty-seven high-risk patients were randomly assigned to one of the three study groups: a mailed-reminder group, a telephone-reminder group, and a control group. Vaccination rates for both reminder methods were significantly higher than for the control group (P less than .02), and if successfully contacted, the telephone-reminder group had a significantly better vaccination rate than the mailed-reminder group (P less than .05). If successful telephone contact can be made, this reminder method is more effective than a letter reminder to increase influenza vaccination rates among high-risk patients.