Fig. 5

Sensitivity analysis of the incremental cost-effectiveness ratio (ICER) of various vaccination strategies for older adults when switching to PCV20 in childhood vaccination, compared to no vaccination. Panel A shows the impact of varying the magnitude of indirect protection or serotype replacement. The main analysis assumes 80% indirect protection with 100% serotype replacement (pneumococcal incidence levels returning to pre-indirect effects level). Panel B shows the impact of varying the time between the switch to PCV20 in childhood vaccination and the vaccination of older adults. The main analysis assumes older adults to be vaccinated in the year of switching (year 0 in the graph). Year 8 in the graph means that older adults are vaccinated 8 years after the implementation of PCV20 in childhood vaccination. Results are presented for a 65-year-old cohort with a 70% vaccination coverage, followed for 15 years. The vaccine price of PCV21 was assumed to be equal to PCV20. 3xPPV23: PPV23 administered at years 0, 5, and 10; PCV15 + 3xPPV23: PCV15 administered at year 0 and PPV23 at years 1, 6, and 11. ICER, incremental cost-effectiveness ratio; PCV, pneumococcal conjugate vaccine; PPV, pneumococcal polysaccharide vaccine; QALY, quality-adjusted life year