Fig. 4

Effect of CSP antibody avidity on protection against the first malaria episode. Kaplan–Meier estimates of time to the first clinical malaria episode during the 12-month follow-up period after the third vaccine dose by the three tertiles (high in grey; medium in blue; low in yellow) of avidity index values at month 3 in RTS,S/AS01E vaccinees. Only plasma/serum samples which IgG concentrations were above the lower limit of quantification (LLOQ) (1.43 EU mL⁻¹ and 2.79 EU mL⁻¹ in NANP (a) and C-terminus [C-term] (b), respectively) were included. The median value for NANP was 0.43 and for C-term 0.11 and the number of subjects included was n = 691 for NANP and n = 698 for C-term. The median survival time (days), i.e., time at which the survivorship function equals 0.5, are shown next to the plots for each strata with the corresponding 95% confidence intervals. p-values assessing differences in the distribution of survival time between the two strata were significant and have been estimated through the Log-rank test. The number of subjects in each tertile are also indicated next to the plots, stratified by age group