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Figure 4 | Malaria Journal

Figure 4

From: The design and statistical power of treatment re-infection studies of the association between pre-erythrocytic immunity and infection with Plasmodium falciparum

Figure 4

The effect of sampling frequency (weeks between each evenly spaced sample assuming no seasonality in transmission) on statistical power and estimated hazard ratio. Statistical power at the 5% significance level to detect the effect of a pre-erythrocytic immune response that prevents 50% of infections in (A) a low transmission setting (EIR = 5), and (B) a high transmission setting (EIR = 150). Mean of estimated hazard ratios for infection associated with a ten-fold increase in antibody titre in (C) a low transmission setting (EIR = 5), and (D) a high transmission setting (EIR = 150).

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