Missed opportunities for vaccination and the delivery of preventive care

Objectives: To evaluate the relative impact of 2 types of missed opportunities (MOs) for vaccination, acknowledged and unacknowledged, on the immunization status of children at 2 years of age and to measure the delivery of immunizations and health care maintenance (HCM) after these types of MOs. Design: Case-control study. Setting: A large multispecialty clinic serving primarily a managed care population in Tucson, Ariz. Patients: Charts of 1165 patients, ages 2 to 4 years, were reviewed for immunization status by 2 years of age. Of these patients, 652 had received all of their medical care at the clinic during their first 2 years of life. The 76 patients found to be underimmunized (UI) at 2 years of age and 76 controls, who were fully immunized (FI) by 2 years of age, frequency matched for age, were studied. Main Outcome Measures: The charts were reviewed for the following information: sex, age, immunizations received, HCM visits, sick visits, MOs, and pediatrician-patient interchange regarding immunization status during visits. Results: Of the children who received all their care at the study site, 88% were FI. The mean number of MOs per patient occurring during the first 2 years of life was 5.8 for the UI children and 2.6 for the FI children. Only an unacknowledged MO, defined as a visit when the patient's immunization status was not reviewed, was associated with having a deficient immunization status at 2 years of age (4.6 vs 1.7, P<.001). Acknowledged MOs did not differ between UI and FI children (0.95 vs 0.76, P=.67). Immunizations were received at the subsequent visit (within a month) twice as often following a visit at which the child's deficient immunization status was acknowledged and a plan for follow-up made (P<.001). However, HCM was often not completed at the return visit. Following acknowledged MOs, patients did not return as directed 25% of the time for UI children and 5% of the time for FI children. Only 30% of FI patients completed the number of HCM visits recommended by the American Academy of Pediatrics. Conclusions: In the population studied, lack of review of the patients' immunization status was the primary cause of MOs to vaccinate. Although patients returned significantly more frequently when informed of their child's deficient immunization status, poor follow-up remained a significant problem in children who were eventually found to be lacking immunizations at 2 years of age.