This study focuses on implementing and evaluating an evidence-based collaborative method of increasing immunization rates among preschool children, adolescents and adults within an Accountable Care Organization-Public Health collaborative. The infrastructure we will create through this project will serve as the framework for future collaborative delivery of other preventive services.

The current project leverages newly formed Regional Care Collaborative Organizations (RCCO) in Colorado that are charged with providing comprehensive care for children and adults insured by Medicaid. With a new RCCO-public health collaborative we will implement a randomized controlled trial to test the effectiveness of 1) evidence-based collaborative centralized method of increasing immunization delivery using reminder/recall techniques versus 2) traditional practice-based reminder/recall techniques that are done by individual practices (not centrally) or usual care from their provider. These interventions have been previously developed by the study team in different clinical settings. The project will examine the collaborative centralized approach, implemented within the new RCCO-public health collaborative first among preschool children, the group in which it has been previously studied. We will then extend the method to new populations, including adolescents and adults within the RCCO and Denver Health (adults only), and will evaluate the effectiveness of the intervention in each population.

Inclusion Criteria:

• Patients enrolled in Regional Care Collaborative Organizations (RCCOs) study practices in the regions covered by Colorado Access,
• Age 19-35 months,
• Age 11-17 years, or
• Age 18 years and older.
• Require an immunization according to Advisory Committee on Immunization Practices (ACIP) guidelines,
• Adult (18 and older) patients at 8 primary care sites who are enrolled in Denver Health and patients at 6 primary care RCCO study practices

Exclusion Criteria:

• Any child whose parents have requested removal from the immunization registry;
• Any adult who has requested removal from the immunization registry;
• Any child or adult with hypersensitivity to any component of one of the recommended vaccines;
• Any child or adult who has moved to a primary care provider other than one at the study practices.