Increasing immunization: a Medicaid managed care model.

OBJECTIVE To evaluate the impact of an immunization outreach program on immunization rates. SETTING A Pennsylvania independent practice association model managed care organization (100% Medicaid). DESIGN Retrospective cohort study (N = 2511) of children 30 to 35 months of age from two age cohorts that compared immunization rates for Advisory Committee on Immunization Practices schedules for diphtheria-tetanus-pertussis, oral polio vaccine, measles-mumps-rubella, and Haemophilus influenza type b. An evaluation of the outreach component of the program compared treatment and nontreatment subgroups of one age cohort (N = 1002). INTERVENTION The immunization program targeted approximately 19 000 members from birth to 6 years of age. The program components included computerized tracking and reminders, member and provider education, provider incentives, member incentives, and home visiting outreach. RESULTS Data indicate that the treatment group has higher completed immunization rates at 35 months of age than does the control group. Furthermore, data show that members with home visits have significantly higher completed immunization rates than do other members. The corresponding comparisons for age-appropriate immunizations by 24 months indicate a nonsignificant trend of increased rates. CONCLUSION The data provide evidence supporting a correlation between comprehensive strategies (computerized tracking, member and provider education and incentives, and home visiting) and increased immunization rates. Those individuals who received home visits were more likely to complete an immunization series by 35 months of age than those who did not. However, within the Mercy Health Plan program, age-appropriate immunizations are not significantly affected by home-visiting outreach.