Rates of immunization of children and adults in the United States have
been increasing, but are still below national goals. Szilagyi and colleagues
systematically reviewed studies on the effectiveness of patient reminder systems
(postcards, letters, and telephone or autodialer calls) to improve immunization
rates. In 33 of the 41 reviewed studies, patient reminder systems improved
immunization rates independent of baseline immunization rates, patient age,
clinical setting, or vaccination type. All types of reminders were effective;
telephone reminders were the most effective, but the most costly.