Table 3.
Model to estimate mean half-life of antibodies and its variation considering demographic and clinical characteristics.
| Univariate model | Multivariate model | ||||
|---|---|---|---|---|---|
| Estimate | 95% CI | Estimate | 95% CI | ||
| Baseline model | Initial titer | 6.55 | (6.20 - 6.93) | 6.05 | (5.31 - 6.89) |
| half-life | 146.3 | (138.6 - 154.9) | 121.4 | (109.1 - 136.6) | |
| Age model | Initial titer: < 45 years | 6.49 | (6.03 - 6.98) | – | – |
| half-life: < 45 years | 141.1 | (131.4 - 152.2) | – | – | |
| Δ Initial titer: > 45 years | 0.36 | (−0.32 - 1.23) | 0.33 | (−0.30 - 1.23) | |
| Δ half-life: > 45 years | 10.1 | (−5.0 - 35.5) | 10.5 | (−1.4 - 33.2) | |
| Sex model | Initial titer: Male | 6.81 | (6.12 - 7.57) | – | – |
| half-life: Male | 146.2 | (132.3 - 163.5) | – | – | |
| Δ Initial titer: Female | −0.34 | (−0.99 - 0.57) | 0.35 | (−0.35 - 1.36) | |
| Δ half-life: Female | 0.1 | (−13.3 - 26.6) | −0.5 | (−9.7 - 17.5) | |
| Exposure Risk model | Initial titer: Low risk | 6.48 | (5.89 - 7.12) | – | – |
| half-life: Low risk | 135.8 | (124.7 - 149.1) | – | – | |
| Δ Initial titer: High risk | 0.12 | (−0.56 - 1.03) | 0.22 | (−0.41 - 1.12) | |
| Δ half-life: High risk | 16.3 | (−0.1 - 46.4) | 14.1 | (0.6 - 40.2) | |
| Infection Category model | Initial titer: Asymptomatic/Mild | 6.53 | (6.17 - 6.92) | – | – |
| half-life: Asymptomatic/Mild | 145.6 | (137.7 - 154.4) | – | – | |
| Δ Initial titer: Moderate/ Severe | 0.36 | (−0.97 - 2.24) | 0.07 | (−1.01 - 1.82) | |
| Δ half-life: Moderate/ Severe | 11.3 | (−17.2 - 70.5) | 3.1 | (−13.9 - 43.0) | |
| COVID-19 Symptoms model | Initial titer: No | 6.26 | (5.76 - 6.80) | – | – |
| half-life: No | 138.0 | (127.9 - 149.8) | – | – | |
| Δ Initial titer: Yes | 0.54 | (−0.16 - 1.45) | 0.34 | (−0.30 - 1.25) | |
| Δ half-life: Yes | 15.4 | (−0.5 - 43.1) | 14.1 | (0.9 - 39.8) | |
COVID-19: Coronavirus Disease 2019; SARS-CoV-2: Severe Acute Respiratory Syndrome Coronavirus 2; IgG: Immunoglobulin G.