Table 1.
Participants characteristics
| Characteristic | Total (N = 304) | Naive vaccinated (n = 107) | Infected vaccinated (n = 42) | Vaccinated infected (n = 155) |
|---|---|---|---|---|
| Age, years; median (IQR) | 31 (27–44) | 30 (26–43) | 32 (28–46) | 31 (27–45) |
| 21–29, n (%) | 134 (44.1) | 52 (48.6) | 12 (28.6) | 70 (45.2) |
| 30–39, n (%) | 68 (22.4) | 21 (19.6) | 18 (42.9) | 29 (18.7) |
| 40–49, n (%) | 57 (18.8) | 23 (21.5) | 4 (9.5) | 30 (19.3) |
| 50–59, n (%) | 45 (14.8) | 11 (10.3) | 8 (19.0) | 26 (16.8) |
| Gender | ||||
| Women, n (%) | 235 (77.3) | 83 (77.6) | 30 (71.4) | 122 (78.7) |
| Men, n (%) | 69 (22.7) | 24 (22.4) | 12 (28.6) | 33 (21.3) |
| No. of previous SARS-CoV-2 infections, n (%) | ||||
| 0 | 107 (35.2) | 107 (100.0) | 0 (0.0) | 0 (0.0) |
| 1 | 176 (57.9) | 0 (0.0) | 27 (64.3) | 149 (96.1) |
| 2 | 21 (6.9) | 0 (0.0) | 15 (35.7) | 6 (3.9) |
| Comorbidities, n (%) | ||||
| No | 243 (79.9) | 88 (82.2) | 34 (81.0) | 121 (78.1) |
| Yes | 61 (20.1) | 19 (17.8) | 8 (19.0) | 34 (21.9) |
| Obesity | 39 (12.9) | 13 (12.2) | 6 (14.3) | 20 (12.9) |
| Cardiovascular disease (including hypertension) | 20 (6.6) | 6 (5.6) | 2 (4.8) | 12 (7.7) |
| Asthma | 7 (2.3) | 2 (1.9) | 1 (2.4) | 4 (2.6) |
| Diabetes mellitus | 4 (1.3) | 2 (1.9) | 1 (2.4) | 1 (0.7) |
| Data before mRNA-1273 booster dose (day 0) | ||||
| Interval between first and second CoronaVac dose, days; median (IQR) | 14 (14–17) | 14 (14–17) | 28 (14–31) | 14 (14–14) |
| Interval between second CoronaVac dose and mRNA-1273 booster, days; median (IQR) | 190 (165–232) | 177 (151–190) | 137 (94–153) | 229 (196–241) |
| Interval between the most recent spike antigen exposure* and mRNA-1273 booster, days; median (IQR) | 104 (89–171) | 177 (151–190) | 111 (92–147) | 92 (79–101) |
| Bab titer, BAU/mL; median (IQR) | 250 (32–1.389) | 32 (15–84) | 125 (42–760) | 963 (292–2,116) |
| Bab seropositivity,† n (%) | 293 (96.4) | 97 (90.7) | 42 (100.0) | 154 (99.4) |
| Data after mRNA-1273 booster dose (day 28) | ||||
| Interval between mRNA-1273 booster and day 28 Bab measurement, days; median (IQR) | 34 (31–36) | 35 (34–39) | 35 (31–43) | 31 (29–34) |
| Bab titer day 28, BAU/mL; median (IQR) | 2,313 (1,226–4,324) | 2,834 (1,228–4,687) | 1,986 (1,153–4,078) | 2,136 (1,299–3,855) |
| Bab seropositivity,† n % | 304 (100) | 107 (100) | 42 (100) | 155 (100) |
Bab = binding antibody; BAU = binding antibody units (according to the WHO International Standard); IQR = interquartile range; mRNA = messenger RNA.
*
Defined as either CoronaVac second dose or breakthrough infection, whichever occurred most recently.
†
Binding antibody seropositivity was defined as ≥ 7.1 BAU/mL.