Public health in managed care: A randomized controlled trial of the effectiveness of postcard reminders

Objectives. This study evaluated the effectiveness of an annual public health intervention in a managed care setting. Methods. Managed care organization members 65 years and older who received influenza immunization in 1996 were randomized to an intervention group (mailed a postcard reminder to receive an influenza vaccination in 1997) or a control group (no postcard). Vaccination rates for both groups were assessed monthly. Results. Members receiving the intervention were no more likely to be immunized (78.6%) than members of the control group (77.2%, P = .222). Members were vaccinated at the same pace regardless of vaccination history and postcard intervention status. Conclusions. Postcard reminders were not an effective intervention among seniors who had been vaccinated the previous year.