Table 4. Incremental Cost-Effectiveness Ratios for SOP by Base Case (18%) and in Sensitivity Analyses on Vaccination Rate Increases for Influenza and Pneumococcal Polysaccharide Vaccines in Persons ≥65 Years of Age.

Strategy	Increase in Vaccination Rate (%)	Cost (C)	Incremental Cost (ΔC)	Effectiveness (E, QALY)	Incremental Effectiveness (ΔE)	ICER (ΔC/ΔE)
No SOP	18	$740.47		11.4605
SOP		$831.45	$90.99	11.4669	0.0064	$14,171
No SOP	0	$740.47		11.4605
SOP		$803.25		11.4605		(Dominated)
No SOP	1	$740.47		11.4605
SOP		$804.80	$64.33	11.4608	0.0004	$180,429
No SOP	2	$740.47		11.4605
SOP		$806.36	$65.89	11.4612	0.0007	$92,395
No SOP	3	$740.47		11.4605
SOP		$807.92	$67.45	11.4615	0.0011	$63,052
No SOP	5	$740.47		11.4605
SOP		$811.04	$70.57	11.4623	0.0018	$39,579
No SOP	10	$740.47		11.4605
SOP		$818.86	$78.40	11.464	0.0036	$21,982
No SOP	20	$740.47		11.4605
SOP		$834.62	$94.15	11.4676	0.0071	$13,196

QALY: quality adjusted life year; ICER: Incremental cost-effectiveness ratio ($/QALY); SOP: standing order program.