Extended Data Fig. 9: Performance of assay is dependent on time between blood draws and measurement error.

Optimization of assays for the detection of events in which the specificity is maintained at >95%. a–c, We explore the performance of three different assay testing protocols: current practice for which infection events are defined as a rise above a cutoff point in any serotype across two blood draws (a), a ‘mean approach’ for which the mean across all serotypes is first calculated before comparing the means across time points (b), a ‘mean approach’ for which titres are available on a continuous scale (c). For each protocol, we identify the optimal cutoff point for a range of assay measurement errors from 100,000 simulated titres based on the fitted titre responses from infections in our study population, that maintains a specificity of >95% (top row). We then calculate the sensitivity of the approach for different time intervals between blood draws using 50% held-out data (bottom row). d–f, Same as a–c but using a more stringent cutoff of 99%.