Table 2.
Anti-SARS-CoV-2 IgG and NAbs titers, and proportion of seropositive LTRs at each collection time point.
| LTR Participants | |||||
|---|---|---|---|---|---|
| Day of Collection | Anti-SARS-CoV-2 IgG (BAU/mL) | IgG-seropositive LTRs, n (%) | NAbs (AU/mL) | NAbs-seropositive LTRs, n (%) | IgG and/or NAbs Seropositive LTRs, n (%) |
| Day 0 (n = 49) |
2.1 (2.0–2.2) | 0 (0.0) | 4.3 (3.8–4.7) | 1 (2.0) | 1 (2.0) |
| Day 28 (n = 47) |
2.7 (1.9–3.8) | 1 (2.1) | 4.2 (3.9–4.5) | 2 (4.2) | 3 (6.4) |
| Day 84 (n = 49) |
6.1 (0.7–11.6) | 2 (4.0) | 6.2 (3.3–9.0) | 4 (8.2) | 4 (8.2) |
| Day 112 (n = 44) |
12.1 (0.4–23.8) | 3 (6.8) | 11.7 (2.3–21.0) | 5 (11.4) | 5 (11.4) |
| Day 180 (n = 42) a |
9.7 (0.6–18.7) | 3 (7.2) | 6.3 (3.8–8.8) | 4 (10.0) | 5 (11.9) |
| Day 210 (n = 32) b |
12.8 (0.0–26.4) | 3 (9.3) | 8.0 (3.7–12.2) | 4 (12.9) | 4 (12.5) |
| Day 238 (n = 28) |
197.8 (0.0–491.4) * | 9 (32.2) | 76.6 (0–159.6) # | 9 (32.2) | 9 (32.2) |
IgG titers and neutralizing antibodies (NAbs) titers are expressed as mean ± 95% CI. * p < 0.05 for comparison between day 238 vs all timepoints by the Kruskal–Wallis test followed by a post hoc Dunn’s test. # p < 0.01 for comparison between day 238 and days 0, 28, and 84 by the Kruskal–Wallis test followed by a post hoc Dunn’s test. a Two missing values for NAbs measurement due to insufficient serum volume. b One missing value for NAbs measurement due to insufficient serum volume.