Table 3.
Descriptive statistics of variables and clinical outcomes collected at each visit.
| Pre-vaccine 1 (n = 551) |
Post-2 weeks (n = 515) |
Post-10 weeks (n = 519) |
Post-24 weeks (n = 499) |
|
|---|---|---|---|---|
| Potential exposure to SARS-CoV-2 | ||||
| At least 1 occupational-related exposure | 310 (56%) | 138 (27%) | 196 (38%) | 285 (57%) |
| List of occupational-related exposure | ||||
| Perform nasopharyngeal swabbing | 101 (18%) | 37 (7%) | 49 (9%) | 94 (19%) |
| Face-to-face exposure (with or without PPE) | 192 (35%) | 67 (13%) | 130 (25%) | 178 (36%) |
| Provide care to COVID-19 patients | 162 (29%) | 67 (13%) | 123 (24%) | 177 (35%) |
| Perform aerosol-generating procedure | 84 (15%) | 35 (7%) | 62 (12%) | 88 (18%) |
| Handling biospecimen of COVID-19 patients | 139 (25%) | 69 (13%) | 94 (18%) | 138 (28%) |
| Contact with COVID-19 environment | 162 (29%) | 66 (13%) | 105 (20%) | 157 (31%) |
| Close contact to COVID-19 casea | ||||
| At work | – | 18 (3%) | 69 (13%) | 179 (36%) |
| Outside work | – | 0 (0%) | 14 (3%) | 49 (10%) |
| Compliance to SOPb | ||||
| At workplace | 520 (95%) | 481 (93%) | 496 (96%) | 474 (95%) |
| At public placesb | 530/546 (97%) | 487/513 (95%) | 498/511 (97%) | 480/492 (98%) |
| During social eventsb | 530/546 (97%) | 488/515 (95%) | 500/513 (97%) | 484/495 (98%) |
| Clinical outcomes | ||||
| Had symptoms in the past 2 weeks | – | 195 (38%) | 37 (7%) | 70 (14%) |
| Had breakthrough infection in-between visits | – | – | 1 (0.2%) | 56 (10%)d |
| Asymptomatic | – | – | 1/1 (100%) | 11/56 (20%) |
| Mild symptoms | – | – | 0/1 (0%) | 45/56 (80%) |
| Presumed source of infectionc | ||||
| Handling COVID-19 patients at work | – | – | – | 16/56 (28%) |
| From healthcare colleagues | – | – | – | 11/56 (20%) |
| From household members | – | – | – | 15/56(27%) |
| From community or friends (not from the same household) | – | – | – | 5/56 (9%) |
| Unknown | – | – | – | 9/56 (16%) |
PPE, personal protection equipment, SOP, standard operating procedures.
Close contact and symptoms data were collected only after complete vaccination.
Some participants did not visit public places or attend social events within 1 month when prompted to answer compliance questions. Hence, the compliance to SOP questions did not apply to these participants. The number of participants, who answered compliance, is noted as the denominator.
Self-reported presumed source of infection for the 56 breakthrough infections that occurred between 10 and 24 months post-vaccination.
There were 3, 20, 27 and 6 breakthrough infections that occurred at 3-, 4-, 5-, and 6-month post-vaccination, respectively.