Pediatric influenza immunization in an integrated safety net health care system

Objective: In 2008 the Advisory Committee on Immunization Practices (ACIP) of the Centers for Disease Control and Prevention (CDC) recommended that all children aged 6 months to 18 years receive annual influenza vaccine. Full pediatric influenza administration has proven difficult. We compared rates of full influenza immunization between a safety net health care system and CDC sentinel sites and evaluated sociodemographic factors associated with full influenza immunization.

Patients and methods: We matched influenza immunization data for 2008-2009 from a health care system immunization registry with patient demographic/billing data and compared rates to CDC sentinel sites using bivariate analysis. We evaluted immunization rates by patient characteristics using multivariate analysis.

Results: Full influenza immunization was achieved in 32% of Denver Health (DH) children compared to 12% at the CDC sites (p<0.001). The largest differences occurred in children aged 11-12 and 13-18 years, 47% DH vs 12% CDC sites, and 33% DH vs 9% CDC sites respectively, (p<0.001 for both). In multivariate analysis, DH children were more likely to be immunized if they were Asian, Odds Ratio (OR) 1.59 95%CI (CI) 1.32-1.91, or Hispanic OR 1.18 CI 1.07-1.30, compared to white, spoke Spanish OR 1.19 CI 1.13-1.26, or other non-English language OR 2.05 CI 1.80-2.34, and had a greater number of visits for well care OR 2.86 CI 2.74-2.98 and sick/follow-up care OR 1.59 CI 1.56-1.62, during the influenza season. They were less likely to be immunized if they had commercial insurance OR 0.68 CI 0.62-0.75 or were uninsured OR 0.77 CI 0.72-0.80, compared to Medicaid/SCHIP.

Conclusions: Using immunization registry prompts, standing orders, multiple sites and visit types for immunization, an integrated safety net health care system had higher full influenza immunization rates than the CDC sentinel sites singularly or collectively. These procedures can be applied elsewhere to improve influenza immunization rates.