Fig. 4.

Prospective risk for SARS-CoV-2 infection and COVID-19 severity in relation to antibody titres. (A) Ab titres at 3-, 6-, and 9-months in patients without a prior history of COVID-19 (and Nucleocapsid Ab titres <5000 AU/ml) in relation to later development of COVID-19. Statistical test performed were Mann–Whitney U test. Correlation between Wu-Hu.1 (B) or BA.1 (C) reactive Ab titres at different sampling timepoints and future COVID-19 severity. Statistical tests performed were Spearman correlation. For sample sizes, please see Table 1. Whiskers for all boxplots represents 1.5× IQR.