Cost-effectiveness analysis of influenza and pneumococcal vaccination for Hong Kong elderly in long-term care facilities

Background: To compare cost and quality-adjusted life-years (QALYs) gained by influenza vaccination with or without pneumococcal vaccination in the elderly living in long-term care facilities (LTCFs). Methods: Cost-effectiveness analysis based on Markov modelling over 5 years, from a Hong Kong public health provider's perspective, on a hypothetical cohort of LTCF residents aged ≥65 years. Benefit-cost ratio (BCR) and net present value (NPV) of two vaccination strategies versus no vaccination were estimated. The cost and QALYs gained by two vaccination strategies were compared by Student's t-test in probabilistic sensitivity analysis (10 000 Monte Carlo simulations). Results: Both vaccination strategies had high BCRs and NPVs (6.39 and US$334 for influenza vaccination; 5.10 and US$332 for influenza plus pneumococcal vaccination). In base case analysis, the two vaccination strategies were expected to cost less and gain higher QALYs than no vaccination. In probabilistic sensitivity analysis, the cost of combined vaccination and influenza vaccination was significantly lower (p<0.001) than the cost of no vaccination. Both vaccination strategies gained significantly higher (p