Fig. 2.

Anti-spike antibody titres in quantitative analysis subset. (A) Post-vaccination titres for all patients in the quantitative analysis subset (n = 18), including patients with no confirmed history of natural infection (n = 8; black) and patients with confirmed history of natural infection (n = 10; red). The dotted line indicates the seropositivity threshold (anti-spike antibody titre ≥ 13). (B) Post-vaccination titres for patients with no confirmed history of natural infection (n = 8; black), post-vaccination pre-infection titres for patients with confirmed history of natural infection (n = 10; red) and post-vaccination post-infection titres for patients with confirmed history of natural infection (n = 10; blue). * p < 0.05. ns, not significant.  (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article.)