The impact of rheumatic diagnosis on neutralising capacity and anti-RBD-IgG levels in patients with AIRD (n=308) compared with controls (n=296)
| Rheumatic diagnosis, n | Neutralising capacity (%) | Anti-RBD-IgG (S/CO) | ||||
| Median (IQR) | Unadjusted p value | Adjusted p value | Median (IQR) | Unadjusted p value | Adjusted p value | |
| Immunocompetent controls, n=296 | 96.5 (93.5–97.1) | (ref) | (ref) | 6.7 (6.3–7.1) | (ref) | (ref) |
| Rheumatoid arthritis, n=128 | 76.9 (35.6–92.9) | <0.001 | 0.888 | 5.1 (0.9–6.4) | <0.001 | 0.666 |
| Psoriatic arthritis, n=45 | 95.3 (83.6–96.7) | 0.108 | 0.583 | 5.9 (3.6–6.9) | <0.001 | 0.190 |
| Axial spondyloarthritis, n=28 | 94.5 (84.5–96.8) | 0.599 | 0.810 | 6.2 (4.2–6.8) | 0.001 | 0.062 |
| Systemic lupus erythematosus, n=33 | 95.3 (90.3–96.7) | 0.001 | 0.215 | 6.3 (3.9–7.0) | <0.001 | 0.901 |
| Systemic sclerosis, n=12 | 96.5 (93.7–96.7) | 0.928 | 0.314 | 6.2 (5.2–6.6) | 0.527 | 0.442 |
| Primary Sjögren's syndrome, n=9 | 95.9 (88.6–96.4) | 0.335 | 0.373 | 6.2 (6.0, 6.7) | – | – |
| Myositis, n=7 | 34.8 (7.7–96.2) | <0.001 | 0.571 | 0.2 (0, 6.3) | <0.001 | 0.477 |
| ANCA-associated vasculitides, n=17 | 11.6 (2.9, 46.1) | <0.001 | 0.758 | 0 (0, 0.6) | <0.001 | 0.580 |
| Polymyalgia rheumatica/giant cell arteritis, n=10 | 95.3 (86.7, 96.4) | 0.586 | 0.659 | 5.3 (4.5, 6.5) | 0.069 | 0.148 |
| IgG4-related disease, n=7 | 94.6 (10.9, 95.8) | 0.011 | 0.587 | 5.5 (0, 6.2) | 0.002 | 0.636 |
| Autoinflammatory syndromes, n=6 | 96.5 (82.8, 97.0) | 0.567 | 0.593 | 6.5 (5.1, 6.9) | 0.491 | 0.399 |
| Other AIRD, n=6* | 91.2 (0, 94.1) | <0.001 | 0.226 | 4 (0, 5.3) | <0.001 | 0.116 |
P values were estimated by a Wald test as combined p value of the two-part model. Statistically significant results in bold. A hyphen indicates that calculation was not possible within the model.
Adjusted multivariable analysis includes the covariates age, sex, BMI, type of vaccination, vaccine interval in days, interval between second vaccination and antibody testing in days, rheumatic diagnosis, comorbidity and immunosuppressive therapy.
*Cogan-syndrome (n=2), peripheral spondyloarthritis (n=2), polychondritis (n=1), sarcoidosis (n=1).
AIRD, autoimmune rheumatic diseases; ANCA, antineutrophil cytoplasmic antibody; BMI, body mass index; RBD, receptor-binding domain; ref, reference; S/CO, signal/cut-off.