Pneumococcal vaccination is underused in underserved minorities, who are at greater pneumococcal disease risk. Two vaccines are available, the older pneumococcal polysaccharide vaccine (PPSV) and the 13-valent pneumococcal conjugate vaccine (PCV13). However, the optimally protective vaccination regimen is unclear, due to changing epidemiology and uncertain vaccine effectiveness; both should become clearer soon. Current CDC vaccination recommendations are complex and may not optimally protect the underserved, due multiple barriers to effective implementation. Vaccine uptake could improve with either better implementation of cur- rent recommendations or broader CDC recommendations that are easier to implement, which could have pro-portionately greater effects on the underserved. Clinical trials comparing these strategies are unlikely and, due to the "moving target" of vaccination-related epidemiologic changes and US Affordable Care Act (ACA) effects on vaccination rates, could be unhelpful. To investigate these issues, a systematic synthesis of available data and evidence-based projections with rigor- ous modeling of uncertainty is planned to assist policymaking and inform research resource allocation. Potential changes to decrease the complexity of pneumococcal vaccination recommendations (using PPSV and/or PCV13) will be modeled and compared to current recommendations implemented under programs to improve vaccination rates. Specific aims are to: 1) compare the public health impact on underserved minority populations of potential CDC adult pneumococcal vaccination recommendations, specifically addressing age-based vs. the more complex comorbidity-based use of vaccine; and 2) determine the public health impact and cost- effectiveness of implementation programs to improve vaccination rates in underserved minorities and persons <65 with high risk conditions, compared to potential CDC vaccination recommendations from Aim 1. Vaccination strategies will be compared via Markov model-based cost-effectiveness analysis, with probabilistic sensitivity analysis and value of information analysis to determine favored strategies and identify the most valuable areas for future research. Analyses will also innovatively use the CDC-recommended RE-AIM framework to evaluate implementation program options and explore interactions between ACA effects, potential CDC recommendations, and race-specific pneumococcal disease characteristics. Since CDC vaccination recommendation evaluations increasingly consider economic analyses, analysis results can be used, as they have previously, to assist vaccination recommendation decisions and potentially change vaccination policy to better protect the underserved.