Table 1. Characteristics of the Protection From Infection Study Population at Their Exposure Event.
| Factor | Events, No. (%) | ||
|---|---|---|---|
| All included in the analysis (n = 4689)a | That did not result in an infection (n = 4137) | That resulted in an infection (n = 552) | |
| Age, median (IQR), y | 50 (40-60) | 50.8 (41.3-60.7) | 47.7 (39.0-56.5) |
| Sex | |||
| Male | 1099 (23.4) | 964 (23.3) | 135 (24.5) |
| Female | 3590 (76.6) | 3173 (76.7) | 417 (75.5) |
| Received 4 vaccine doses during the study period | 1453 (31.0) | 1330 (32) | 123 (22.3) |
| Time from last vaccine dose, median (IQR), d | 123.00 (44.00-152.00) | 116 (42-150) | 147 (106.5-162) |
| Time from serology test to exposure event, median (IQR), d | 14 (8-22) | 14 (8-22) | 14 (8-21) |
| IgG levels, BAU | |||
| 0-500 | 1031 (22.0) | 886 (21.4) | 145 (26.3) |
| 501-1000 | 1158 (24.7) | 998 (24.1) | 160 (29) |
| 1001-2000 | 1161 (24.8) | 1018 (24.6) | 143 (25.9) |
| >2000 | 1339 (28.6) | 1235 (29.9) | 104 (18.8) |
| Neutralizing antibody titer | |||
| 0-512 | 924 (35.2) | 753 (33.3) | 171 (47.2) |
| 1024 | 530 (20.2) | 449 (19.9) | 81 (22.4) |
| 2048-4096 | 847 (32.3) | 760 (33.6) | 87 (24) |
| >4096 | 321 (12.2) | 298 (13.2) | 23 (6.4) |
a
A health care worker could contribute more than 1 event that did not result in an infection but was censored following their first infection.