Table 2.
Data regarding anti-S1/S2 IgG seropositivity (SP) rates, anti-SARS-CoV-2 S1/S2 IgG titres, frequency of neutralising antibodies (NAb) and mean percentage of neutralising activity in spondyloarthritis (SpA) patients and controls (CG) after the first (D28) and second doses (D69) of CoronaVac vaccination.
| After 1st dose |
After 2 doses |
|||
|---|---|---|---|---|
| SpA (n = 176) | CG (n = 162) | SpA (n = 176) | CG (n = 162) | |
| Anti-S1/S2 IgG | ||||
| SP, n (%) | 35 (19.9)a | 49 (30.2) | 141 (80.2)c | 155 (95.7) |
| GMT (95% CI) | 5.6 (4.7–6.6)c | 9.7 (7.9–12.0) | 34.4 (29.4–40.2)c | 68.9 (60.9–78.0) |
| Neutralising antibodies (NAb) | ||||
| NAb presence, n (%) | 37 (21.0)b | 57 (35.2) | 108 (61.6)c | 134 (82.7) |
| Mean neutralising activity, (SD)% | 51.1 (16.4) | 57.4 (21.4) | 61.4 (15.2)a | 66.7 (16.1) |
Seropositivity (SP) is defined as post-vaccination titre ≥ 15 AU/mL by indirect ELISA, LIAISON SARS-CoV-2 S1/S2 IgG. Frequencies of SP are presented as number (%), and were compared using a two-sided Chi2 test between SpA patients and CG at pre-specified time points (D28 and D69). IgG antibody titres are expressed as geometric means (GMT) with 95% confidence interval (CI). Data regarding IgG titres were analysed using generalised estimating equations (GEE) with normal marginal distribution and gamma distribution respectively and identity binding function assuming first order autoregressive correlation matrix between moments (D0, D28 and D69) in the comparison of the 2 groups (SpA vs. CG), followed by Bonferroni's multiple comparisons. The behavior of IgG titres was different for SpA and CG groups between D28 and D69: mean titres increased at each time point for SpA and CG (P < 0.001). All analyses were two-sided. Frequencies of subjects with positive NAb are expressed as number (%). Positivity for NAb was defined as neutralising activity ≥ 30% (cPass sVNT Kit). Data were compared using a two-sided Chi2 test between SpA patients and CG at pre-specified time points (D28 and D69). Percentages of neutralising activity among subjects with positive NAb are expressed as mean (± standard deviation – SD). Data were compared using a two-sided Mann–Whitney U-test for comparison between SpA patients and CG, at pre-specified time points (D28 and D69).
For comparisons between SpA patients and CG: P < 0.05.
For comparisons between SpA patients and CG: P < 0.01.
For comparisons between SpA patients and CG: P < 0.001.