Fig. 4.

Vaccine price and efficacy relationship with standardized cost-effectiveness (ICER/WTP) stratified by country income level. The ICER uncertainty from Hontelez et al. [28] is reported in one direction as a result of the threshold analysis method to set the vaccine price, resulting in an ICER equal to the country-specific willingness to pay. Three authors are included twice to reflect different results from multiple publications (Long [26, 27] and Moodley [31, 32]) and analysis of two populations in one publication (Harmon et al. [30]). Amirfar et al. [24] and Stover et al. [33] did not explicitly state cost-effectiveness thresholds. The threshold from Harmon et al. [30] was applied to the Stover et al. [33] study as both model the same 26 countries. Standardized ICER = ICER/WTP. ICER incremental cost-effectiveness ratio. WTP willingness to pay per health unit gained