Fig. 3: Anti–SARS-CoV-2 antibody concentration levels.

Anti-spike IgG antibody levels in patient samples were measured using Abbott’s SARS-CoV-2 IgG II Quant ARCHITECT assay. Comparing these antibody concentrations, the one-dose J&J vaccine induces lower antibody levels than the two-dose Pfizer and Moderna vaccines. There is no significant difference in mean concentrations between individuals vaccinated with Pfizer vs Moderna (the Tukey HSD test p-value = 0.5108). However, there is a significant difference in antibody concentration levels across the three groups as determined by ANOVA (F-test p-value = 0.0001), and pairwise Tukey HSD (Pfizer vs J&J: p-value = 0.0019; Moderna vs J&J: p-value = 0.0000). The number of samples tested was 26, 19, and 29 for Pfizer, Johnson & Johnson, and Moderna, respectively.