Cost-effectiveness of increasing vaccination in high-risk adults aged 18–64 Years: a model-based decision analysis

BACKGROUND Adults aged 18-64 years with comorbid conditions are at high risk for complications of certain vaccine-preventable diseases, including influenza and pneumococcal disease. The 4 Pillars™ Practice Transformation Program (4 Pillars Program) increases uptake of pneumococcal polysaccharide vaccine, influenza vaccine and tetanus-diphtheria-acellular pertussis vaccine by 5-10% among adults with high-risk medical conditions, but its cost-effectiveness is unknown. METHODS A decision tree model estimated the cost-effectiveness of implementing the 4 Pillars Program in primary care practices compared to no program for a population of adults 18-64 years of age at high risk of illness complications over a 10 year time horizon. Vaccination rates and intervention costs were derived from a randomized controlled cluster trial in diverse practices in 2 U.S. cities. One-way and probabilistic sensitivity analyses were conducted. RESULTS From a third-party payer perspective, which considers direct medical costs, the 4 Pillars Program cost $28,301 per quality-adjusted life year gained; from a societal perspective, which adds direct nonmedical and indirect costs, the program was cost saving and more effective than no intervention. Cost effectiveness results favoring the program were robust in sensitivity analyses. From a public health standpoint, the model predicted that the intervention reduced influenza cases by 1.4%, with smaller decreases in pertussis and pneumococcal disease cases. CONCLUSION The 4 Pillars Practice Transformation Program is an economically reasonable, and perhaps cost saving, strategy for protecting the health of adults aged < 65 years with high-risk medical conditions.