Extended Data Fig. 9. Ct values in new PCR-positives ≥14 days after second vaccination.

(a) by months since second vaccination (N = 1,736), (b) by age (N = 1,736) and (c) by most recent anti-trimeric spike IgG antibody measurement where available (N = 846). Note: in (a) red solid line shows 30 threshold used in main analysis. Short red lines show median within groups. In (c) antibody measurements taken median 30 (IQR 28-54) [range 25–91] days before the new PCR-positive, at or before the most recent prior negative swab and 14 days or more after first vaccination. 42 ng/ml is the positivity threshold. Overall association with Ct Spearman rho=0.08 (p = 0.002) for age (b), and 0.10 (p = 0.002) for IgG (c). P-values for the Spearman tests were obtained using a two-side t-test.