The overall goal of this project is to enhance the nation's ability to vaccinate adolescents in primary care practices (medical homes). Most adolescents have a medical home, and prior studies demonstrate that enhancements are needed in medical homes to efficiently vaccinate adolescents. The project will identify and rigorously evaluate a feasible and sustainable strategy for improving adolescent vaccinations within medical homes. We will work with two primary care practice-based research networks (PBRNs)-a regional network (85 practices) and a national network of academic-based medical homes (110 practices), to evaluate a multi-component adolescent vaccination strategy. This strategy will be evaluated in a diverse spectrum of medical homes that vary by specialty (pediatrics, family medicine), patient population (high and lower income), practice type (private, clinic, health center), and teaching role (practices with and without residents). The aims are to: 1. Perform formative quantitative surveys of practitioners from all practices in the networks and qualitative interviews of practitioners and parents to identify feasible and sustainable adolescent vaccination strategies. We will use a modified Delphi technique to select the most optimal strategy to evaluate;2. Design and implement a randomized controlled trial, with 6 intervention practices and 6 standard-of-care control practices within each PBRN (n=24 practices). We will use standardized chart reviews (n=3,840 adolescents, 160 per practice) to measure baseline rates of immunizations, missed opportunities, preventive visits, and other visits. We will implement a multi-component strategy;and asses the same measures at 18-month follow-up. We will use bivariate and multivariate analyses to assess the impact of the strategy on the key measures, for the entire population and for subgroups of patients and practice types;3. Evaluate the impact of the strategy on receipt of preventive services by assessing preventive visits and services from the Guidelines for Adolescent Preventive Services, before and after the 18m intervention;4. Evaluate costs and cost-effectiveness, as well as the feasibility of the strategy, using standardized assessments of personnel/non-personnel resources and surveys of physicians to gauge perceptions;5. Work with consultants and national organizations (AAP, AAFP, APA, SAM, CDC) to disseminate findings;develop a toolkit for medical homes to implement best strategies for adolescent vaccinations. Our team has been at the forefront of research in childhood, adult, and now adolescent immunization delivery. We have longstanding experience in interventions involving medical homes, and analyses of resources and costs. By rigorously evaluating the effectiveness of a feasible practice-based strategy across a wide spectrum of patients and practices, this study will provide critical information for practitioners and leaders in immunization and public health to implement strategies to enhance adolescent immunizations and preventive care. PUBLIC HEALTH RELEVANCE: Due to the recent recommendation of three new adolescent vaccines (meningococcus, pertussis, and HPV vaccines) and two new vaccine recommendations for adolescents (influenza and varicella), adolescent vaccinations have become a major new priority area for public health. Currently, adolescent vaccination rates are low. Primary care practices or medical homes are the major sources of healthcare for the majority of adolescents across the US, yet evidence is needed for feasible and sustainable strategies, within medical homes, to optimize adolescent vaccination delivery. This study will provide critical information for pediatrics, adolescent medicine, and public health regarding practical strategies for vaccinating adolescents, the cost of these strategies, and the potential spillover benefits for improving other preventive services by enhancing vaccination of adolescents in medical homes.