Effectiveness of primary care-public health collaborations in the delivery of influenza vaccine: a cluster-randomized pragmatic trial.

Objective: To assess effectiveness and feasibility of public-private collaboration in delivering influenza immunization to children.

Methods: Four pediatric and four family medicine (FM) practices in Colorado with a common public health department (PHD) were randomized at the beginning of baseline year (10/2009) to Intervention (joint community clinics and PHD nurses aiding in delivery at practices); or control involving usual care without PHD. Generalized estimating equations compared changes in rates over baseline between intervention and control practices at end of 2nd intervention year (Y2=5/2011). Barriers to collaboration were examined using qualitative methods.

Results: Overall, rates increased from baseline to Y2 by 9.2% in intervention and 3.2% in control (p<.0001), with significant increases in both pediatric and FM practices. The largest increases were seen among school-aged and adolescent children (p<.0001 for both), with differences for 6-month-old to 5-year-old children and for children with high-risk conditions not reaching significance. Barriers to collaboration included uncertainty regarding the delivery of vaccine supplies, concerns about using up all purchased vaccine by practices, and concerns about documentation of vaccination if collaboration occurred.

Conclusions: In spite of barriers, public-private collaboration resulted in significantly higher influenza immunization rates, particularly for older, healthy children who visit providers less frequently.