Fig. 2.

Quantitative serological response in relation to number of vaccine doses and SARS-CoV-2 infection (COVID-19). (A) Box plot showing Spike Wu-Hu.1 stratified based on COVID-19 status as defined by prior positive COVID-19 test (PCR/RAT) and/or anti-nucleocapsid Ab titres >5000 AU/ml. Subgroup analysis of Spike Wu-Hu.1 Ab titres following three (B) and four (C) vaccine doses ordered by the mean Ab-titre levels in each subgroup. Only subgroups with more than five recorded samples are displayed. All Ab titres were quantified using V-PLEX Serology Panels (MSD). Statistical tests performed were Mann–Whitney with Bonferroni correction for multiple comparisons. The star annotation (∗) indicates statistical significance at a p-value threshold of 0.05 (or ∗∗ for p < 0.01, ∗∗∗ for p < 0.001, ∗∗∗∗ for p < 0.0001). For sample sizes, please see Table 1. Whiskers for all boxplots represents 1.5× IQR.