To measure immunization coverage rates for children enrolled in a statewide Medicaid managed care program and determine the impact of sociodemographic characteristics and the type of primary care provider site on immunization coverage.
A random sample of 2000 was chosen from children between the ages of 19 and 35 months who had been continuously enrolled in the Medicaid managed care program for 1 year. Sociodemographic data and a list of primary care providers for the study children were obtained from administrative databases. Immunization histories were determined by medical record review.
Vaccine-specific immunization rates for diphtheria-tetanus-pertussis, polio, Haemophilus influenzae type b, hepatitis B, and measles-mumps-rubella ranged from 87% to 94%, with an overall coverage rate of 75%. Overall immunization status varied by primary care provider site as follows: office-based, 72%; community health center, 75%; hospital-based clinic, 79%; and staff model health maintenance organization, 85% (chi(2) test, P =.008).
Immunization rates compare favorably with national rates for this low-income group. Sociodemographic characteristics were not important predictors of underimmunization, but rates did vary by the type of primary care provider site.