Figure 3. CCP recipient D0 posttransfusion and matched donor antibody levels stratified by duration from symptom onset to transfusion using cutoffs established by the ROC and maximum antibody threshold method.

(A) RCDCs illustrating antibody distribution of early and late CCP recipients and placebo controls, and thresholds (red dashed lines), established by the maximum antibody that best distinguished hospitalized from nonhospitalized cases. Early recipients are delineated at 2.06 log₁₀(anti–S-RBD AUC) (115 AUC), while late recipients are delineated at 2.58 log₁₀(anti–S-RBD AUC) (380.2 AUC). Curves exclude 5 early participants and 1 late control participant whose posttransfusion plasma was not available. The n values shown are CCP recipients (n = 171 early, n = 190 late) plus placebo recipients (n = 161 early, n = 200 late). (B) Screen seronegative, unvaccinated recipient D0 posttransfusion antibody (n = 361) segregated by early versus late administration assessed as days from symptom onset to transfusion and high versus low antibody using early/late stratum-specific cutoffs established by the maximum antibody that best distinguished hospitalized from nonhospitalized cases. Subsequently hospitalized (red) and nonhospitalized (blue) recipients are shown. The n values and percentages in each quadrant are the proportion hospitalized among quadrant total. (C) Predicted probabilities of hospitalization across early versus late and high versus low categories among screen seronegative, unvaccinated CCP recipients estimated using Firth’s logistic regression adjusted for age, sex, BMI, and variant. P values that predicted the probability is greater than 0% (represented by the horizontal dashed line) are shown for each category, with P < 0.05 considered significant.