Fig. 7.

Persistence of the anti-RBD antibody response. A) Solid symbols represent those negative results from patients that that later seroconverted. BR displayed on log2 scale. Duration of follow-up shown in weeks. Dotted line is cut-off. A total of 737 samples are shown from 109 patients, 68 samples from 18 patients were unreactive. Three patients seroconvert during follow up. Ten sero-positive patients sero-revert to become sero-negative (32 samples). Five patients are persistently sero-negative (33 samples) but have a positive-PCR result listed, 2 of their samples displayed borderline binding ratios of between 0.8 and 0.9. B) Evolution of anti-RBD total antibody assayed over time in a minority of ten patients who sero-reverted during follow-up. Coloured symbols represent individual patients. Three patients received a single dose of Pfizer vaccine prior to their two final samples.