Combination vaccine use and vaccination quality in a managed care population.

Objective: To evaluate the impact of a pentavalent combination vaccine on childhood immunization coverage rates and timeliness within a managed care organization.
Study Design: Retrospective matched-cohort analysis of encounter data from administrative claims and a state immunization registry.
Methods: Children were stratified into 2 demographically matched cohorts (combination and reference), based on receipt of the DTaP/HepB/IPV combination vaccine. Children were followed until 24 months of age, and coverage rates and on-time rates were assessed. Outcomes were measured for the HEDIS Combination 2 vaccine series (4 doses of diphtheria/tetanus/pertussis, 3 doses of polio, 1 dose of measles/mumps/rubella, 3 doses of Haemophilus influenzae type b, 3 doses of hepatitis B, and 1 dose of varicella) and each vaccine series individually.
Results: Children in the combination cohort were significantly more likely to be fully vaccinated for the HEDIS Combination 2 series by 2 years of age and to be vaccinated within the recommended age ranges. In the combination cohort 86.9% (752/865) of patients were fully covered compared with only 74.1% (641/865) of the reference cohort (P <.001). In the combination cohort 45.2% (391/865) of patients received vaccinations on time versus 37.5% (324/865) of the reference cohort, P = .001.
Conclusions: Receipt of DTaP/HepB/IPV was associated with improved coverage and age-appropriate immunization in a managed care population.