Table 3.
Seropositivity and seroprotection according to age, sex, and BMI.
| Characteristics | N | Anti-RBD titer (Architect) |
Anti-RBD titer (Elecsys) |
||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Seropositivity ≥ 50 [AU/mL] |
Seroprotection ≥ 5458 [AU/mL] |
Seropositivity ≥ 0.8 [U/mL] |
Seroprotection > 753 [U/mL] |
||||||||||||||||
| S0 | S1 | S2 | S3 | S0 | S1 | S2 | S3 | S0 | S1 | S2 | S3 | S0 | S1 | S2 | S3 | ||||
| Overall | 385 | 4 (1) | 381 (99) | 385(100) | 385(100) | 0(0) | 2 (1) | 258a (67) | 2 (1) | 1 (<1) | 373 (97) | 385(100) | 385(100) | 0(0) | 2 (1) | 240b (62) | 165c (43) | ||
| Age (years) | |||||||||||||||||||
| 20–29 | 63 | 0 (0) | 63 (100) | 0 (0) | 47 (75) | 1 (2) | 0 (0) | 62 (98) | 2 (3) | 50 (79) | 43 (68) | ||||||||
| 30–39 | 88 | 0 (0) | 88 (100) | 1 (1) | 64 (73) | 1 (1) | 0 (0) | 87 (99) | 0 (0) | 64 (73) | 43 (49) | ||||||||
| 40–49 | 132 | 2 (2) | 130 (98) | 1 (1) | 91 (69) | 0 (0) | 1 (1) | 128 (97) | 0 (0) | 78 (59) | 50 (38) | ||||||||
| 50–59 | 88 | 2 (2) | 86 (98) | 0 (0) | 52 (59) | 0 (0) | 0 (0) | 82 (93) | 0 (0) | 44 (50) | 26 (30) | ||||||||
| 60–64 | 14 | 0 (0) | 14 (100) | 0 (0) | 4 (29) | 0 (0) | 0 (0) | 14 (100) | 0 (0) | 4 (29) | 3 (21) | ||||||||
| P = 0.65 | P = 0.65 | P = 1.00 | P < 0.01 | P = 0.35 | P = 1.00 | P = 0.31 | P = 0.10 | P < 0.01 | P < 0.01 | ||||||||||
| Sex | |||||||||||||||||||
| Male | 126 | 0 (0) | 126 (100) | 0 (0) | 76 (60) | 1 (1) | 0 (0) | 124 (98) | 2 (2) | 79 (63) | 56 (44) | ||||||||
| Female | 259 | 4 (2) | 255 (98) | 2 (1) | 182 (70) | 1 (<1) | 1 (<1) | 249 (96) | 0 (0) | 161 (62) | 109 (42) | ||||||||
| P = 0.31 | P = 0.31 | P = 1.00 | P = 0.051 | P = 0.55 | P = 1.00 | P = 0.35 | P = 0.11 | P = 1.00 | P = 0.66 | ||||||||||
| BMI（kg/m2） | |||||||||||||||||||
| <18.5 | 40 | 2 (5) | 38 (95) | 0 (0) | 33 (83) | 0 (0) | 0 (0) | 36 (90) | 0 (0) | 27 (68) | 22 (55) | ||||||||
| 18.5–24.9 | 279 | 0 (0) | 278 (99) | 2 (1) | 187 (67) | 1 (<1) | 1 (<1) | 272 (97) | 2 (1) | 173 (62) | 118 (42) | ||||||||
| 25–40 | 66 | 2 (3) | 65 (98) | 0 (0) | 38 (58) | 1 (2) | 0 (0) | 65 (98) | 0 (0) | 40 (61) | 25 (38) | ||||||||
| P < 0.01 | P = 0.04 | P = 1.00 | P < 0.01 | P = 0.48 | P = 1.00 | P = 0.046 | P = 1.00 | P = 0.52 | P = 0.11 | ||||||||||
Values in the table are n (%). The thresholds for seropositivity and seroprotection were defined as 1.0 AU/mL and 5458 AU/mL, respectively using the Architect assay; and 0.8 U/mL and 753 U/mL, respectively using the Elecsys assay. P values were calculated using the Mantel-Haenszel chi-square test or Fisher's exact test, depending on the number of participants that exceeded the seropositivity or seroprotection threshold.
BMI: body mass index; anti-RBD: anti-SARS-CoV-2 receptor binding domain spike protein IgG; Architect: Architect SARS-CoV-2 IgG Ⅱ Quant (Abbott Laboratories); Elecsys: Elecsys anti-SARS-CoV-2 S (Roche Diagnostics); S0: Within 1 week before the first vaccination, S1: Within 1 week before the second vaccination, S2: 4–5 weeks after the second vaccination, S3: 6 months after the second vaccination.