Figure 5
Possible factors for variation in vaccine efficacy against acquisition. (a) Prevalence of serotype 19F pre-PCV7 and model-based vaccine efficacy estimates. The decreasing trend suggests that high initial frequency of a serotype for which vaccine protection may be inferior (e.g. 19F) could influence model estimates of the net realized vaccine efficacy against PCV7 serotypes when aggregated together, (R 2 = 47%, (R 2-adj = 11%, GLM fit: ρ = −0.0003, p = 0.10 n.s.). (b) Temperature across countries correlates with vaccine efficacy values estimated by the model (R 2 = 92%, R 2-adj = 87%, GLM fit: ρ = −0.019, p < 0.005 significant), suggesting a possible environmental factor in immunomodulation and vaccination responses. (c) Income inequality, as a proxy for transmission heterogeneity, is associated negatively to realized vaccine efficacy extracted by the model (R 2 = 68%, R 2-adj = 46%, GLM fit: ρ = −0.013, p < 0.05 significant). More details are provided in the Supplementary Tables S4 and S5. The fitted regression lines are displayed in Fig. S7.
