Variation in clinician recommendations for multiple injections during adoption of inactivated polio vaccine

Objectives. To describe variation in clinician recommendations for multiple injections during the adoption of inactivated poliovirus vaccine (IPV) in 2 large health maintenance organizations (HMOs), and to test the hypothesis that variation in recommendations would be associated with variation in im munization coverage rates. Design. Cross-sectional study based on a survey of clinician practices 1 ye ar after IPV was recommended and computerized immunization data from these clinicians' patients. Study Settings. Two large West Coast HMOs: Kaiser Permanente in Northern Ca lifornia and Group Health Cooperative of Puget Sound. Outcome Measures. Imm unization status of 8-month-olds and 24-month-olds cared for by the clinici ans during the study. Results. More clinicians at Group Health (82%), where a central guideline w as issued, had adopted the IPV/oral poliovirus vaccine (OPV) sequential sch edule than at Kaiser (65%), where no central guideline was issued. Clinicia ns at both HMOs said that if multiple injections fell due at a visit and th ey elected to defer some vaccines, they would be most likely to defer the h epatitis B vaccine (HBV) for infants (40%). At Kaiser, IPV users were more likely than OPV users to recommend the first HBV at birth (64% vs 28%) or i f they did not, to defer the third HBV to 8 months or later (62% vs 39%). In multivariate analyses, patients whose clinicians used IPV were as likely to be fully immunized at 8 months old as those whose clinicians used all O PV. At Kaiser, where there was variability in the maximum number of injecti ons clinicians recommended at infant visits, providers who routinely recomm ended 3 or 4 injections at a visit had similar immunization coverage rates as those who recommended 1 or 2. At both HMOs, clinicians who strongly reco mmended all possible injections at a visit had higher immunization coverage rates at 8 months than those who offered parents the choice of deferring s ome vaccines to a subsequent visit (at Kaiser, odds ratio [OR]: 1.2; 95% co nfidence interval [CI]: 1.0-1.5; at Group Health, OR: 1.8; 95% CI: 1.1-2.8) . Conclusions. Neither IPV adoption nor the use of multiple injections at inf ant visits were associated with reductions in immunization coverage. Howeve r, at the HMO without centralized immunization guidelines, IPV adoption was associated with changes in the timing of the first and third HBV. Clinical policymakers should continue to monitor practice variation as future vacci nes are added to the infant immunization schedule.