Sensitivity analysis for D29 markers
ASYMPTOMATIC COVID-19
Stronger evidence for D29 markers may be anticipated, given that individuals with low D29 antibody markers may be at high risk for symptomatic COVID-19 before D57. Accordingly, these high-risk individuals would be included in the analysis of the D29 markers but not the D57 analysis. However, in a setting with lower transmission, there may be fewer such high-risk individuals, and, as such, D29 correlates may not generalize as well to these settings. To study this point, we included a sensitivity analysis that studied the D29 markers and their association with COVID-19 occurring more than 7 days after D57—the identical set of COVID-19 endpoints used in the analysis of the D57 markers. Restricting to post-D57 endpoints attenuated hazard ratio–associated D29 markers, resulting in hazard ratios similar to the D57 markers (