Increasing influenza immunization among high-risk patients: education or financial incentive?

PURPOSE To determine whether an educational brochure or a lottery-type incentive increases influenza immunization rates. PATIENTS AND METHODS In a prospective, single-blind factorial design randomized trial at an urban community health center, all high-risk patients (n = 797) seen in the preceding 18 months were randomly assigned to one of four groups: a control group; a group mailed a large print, illustrated educational brochure emphasizing factors important to patients in making a decision about influenza immunization; a group mailed a lottery-type incentive announcing that all patients receiving influenza immunization would be eligible for grocery gift certificates; and a group mailed both educational brochure and incentive. Immunization was free, available without an appointment, and recorded by a computerized tracking system. RESULTS The group mailed the brochure was more likely to be immunized than control (odds ratio [OR] = 2.29, 95% confidence interval [CI] 1.45 to 3.61), as was the group mailed the incentive (OR = 1.68, 95% CI 1.05 to 2.68), but there was no difference between the group mailed both interventions and the control group. The effectiveness of the brochure was more striking for individuals who had not accepted immunization in the prior year (OR = 4.21, 95% CI 2.48 to 7.14), suggesting a true educational effect rather than simply a reminder. CONCLUSION In this community health center setting, an illustrated educational brochure increased influenza immunization among high-risk patients, a lottery-type incentive was much less effective, and both together was not effective.