Table 5.
Adjusted Risk of SARS-CoV-2 Infection by Exposure to Infected Individuals, Infection Control and Prevention Practices, and Vaccination Status Among High-Risk Caregivers, Stratified by Period
| Variable | Prevaccination Period 15 Nov 2020 to 15 Jan 2021 |
Postvaccination Period 16 Jan 2021 to 29 May 2021 |
||||||
|---|---|---|---|---|---|---|---|---|
| Cases (N = 1,672), % |
Controls (N = 820), % |
aOR | 95% CI | Cases (N = 374), % |
Controls (N = 542), % |
aOR | 95% CI | |
| Household exposure to COVID-19 | 6.4 | 2.8 | 5.1 | 3.0–8.8 | 18.9 | 3.3 | 19.9 | 9.7–40.8 |
| Workplace exposure to COVID-19 patients | 74.3 | 56.3 | 3.4 | 2.6–4.4 | 52.8 | 35.9 | 1.9 | 1.2–3.0 |
| Workplace exposure to COVID-19 coworkers | 62.7 | 44.5 | 1.8 | 1.4–2.4 | 44.4 | 24.0 | 2.7 | 1.7–4.3 |
| IPC training | ||||||||
| None | 1.8 | 2.6 | Ref | 2.4 | 3.3 | Ref | ||
| Only written recommendations | 9.0 | 14.2 | 0.7 | 0.3–1.6 | 8.3 | 11.8 | 1.9 | 0.6–6.5 |
| Any type of training | 89.3 | 83.3 | 1.2 | 0.6–2.6 | 83.2 | 79.8 | 2.5 | 0.9–7.5 |
| Hand washing after patient contact | ||||||||
| Not always | 5.2 | 7.4 | Ref | 6.1 | 7.5 | Ref | ||
| Always | 92.8 | 87.4 | 1.1 | 0.7–1.6 | 82.1 | 73.9 | 0.9 | 0.5–1.9 |
| Workplace masking | ||||||||
| Not always | 4.5 | 5.3 | 4.8 | 8.2 | ||||
| Always | 95.5 | 94.7 | 1.0 | 0.6–1.7 | 95.2 | 91.9 | 0.6 | 0.3–1.4 |
| Physical distancing | ||||||||
| Sometimes/Never | 14.4 | 15.5 | Ref | 18.0 | 16.0 | Ref | ||
| Most of the time | 26.5 | 30.1 | 1.1 | 0.8–1.6 | 23.4 | 29.4 | 0.9 | 0.5–1.6 |
| Always | 59.1 | 54.5 | 1.4 | 1.0–1.9 | 58.5 | 54.6 | 1.4 | 0.8–2.4 |
| Mask use during contact with non–COVID-19 patients | ||||||||
| Not always | 6.0 | 5.8 | Ref | 4.3 | 6.1 | Ref | ||
| Always | 79.5 | 78.5 | 0.8 | 0.5–1.2 | 79.2 | 74.1 | 1.5 | 0.7–3.6 |
| Mask use during non-AGMP contact with COVID-19 patients | ||||||||
| Medical mask | 62.8 | 40.9 | Ref | 36.3 | 19.9 | Ref | ||
| N95 always/most of the time | 6.0 | 7.8 | 0.8 | 0.5–1.2 | 9.9 | 11.0 | 0.6 | 0.3–1.1 |
| Mask use during AGMP contact with COVID-19 patients | ||||||||
| Medical mask | 2.7 | 2.8 | Ref | 2.7 | 2.0 | Ref | ||
| N95 always or most of the time | 5.5 | 12.0 | 0.6 | 0.3–1.1 | 8.0 | 8.8 | 0.6 | 0.2–2.0 |
| Vaccination against COVID-19 | ||||||||
| Unvaccinated | 93.4 | 88.8 | Ref | 54.9 | 26.8 | Ref | ||
| 1 dose 0–13 d before testing | 5.4 | 8.5 | 0.6 | 0.4–0.9 | 15.5 | 7.5 | 1.1 | 0.6–2.1 |
| ≥1 dose ≥14 d before testing | 1.2 | 2.7 | 0.3 | 0.1–0.6 | 29.6 | 65.6 | 0.3 | 0.2–0.5 |
Note. ACH, acute-care hospitals; AGMP, aerosol-generating medical procedures; aOR, adjusted odds ratio; CI, confidence interval; IPC, infection prevention and control; LTCF, long-term care facility; ref, reference category.