Table 1.
Infection rate per 100 person-years overall and by factors, and factors associated with SARS-CoV-2 infection after vaccination.
| Characteristics | Univariate | Multivariate | |||||
|---|---|---|---|---|---|---|---|
| Fixed Covariates | N (%) | Of Events (%) | Event Rate (95% CI) |
Hazard Ratio (95% CI) |
p-Value | Hazard Ratio (95% CI) |
p-Value |
| Overall | 15808 (100%) | 638 (4%) | 6.7 (6.2–7.2) | ||||
| Age | |||||||
| 18–44 (Reference group) | 5169 (33%) | 244 (4.7%) | 8.6 (7.6–9.8) | ||||
| 45-64 | 7485 (47%) | 315 (4.2%) | 6.9 (6.2–7.7) | 0.71 (0.60–0.84) | <0.0001 | 0.70 (0.59–0.82) | <0.0001 |
| 65+ | 3154 (20%) | 79 (2.5%) | 3.7 (3.0–4.6) | 0.35 (0.27–0.45) | <0.0001 | 0.41 (0.32–0.54) | <0.0001 |
| Sex | |||||||
| Female (Reference group) | 11631 (74%) | 471 (4%) | 6.7 (6.1–7.3) | ||||
| Male | 4177 (26%) | 167 (4%) | 6.6 (5.7–7.7) | 0.97 (0.82–1.15) | 0.7387 | 1.11 (0.93–1.32) | 0.2399 |
| Race/Ethnicity | |||||||
| Non-Hispanic White (Reference group) | 14854 (94%) | 611 (4.1%) | 6.8 (6.2–7.3) | ||||
| Non-Hispanic Black | 400 (3%) | 8 (2%) | 3.8 (1.9–7.6) | 0.72 (0.36–1.43) | 0.3484 | 0.7 (0.35–1.41) | 0.3163 |
| Hispanic | 165 (1%) | 6 (3.6%) | 7.0 (3.1–15.6) | 1.24 (0.56–2.75) | 0.6041 | 0.96 (0.43–2.16) | 0.9289 |
| Non-Hispanic Other | 389 (2%) | 13 (3.3%) | 6.2 (3.6–10.7) | 1.04 (0.61–1.78) | 0.8785 | 1.01 (0.59–1.73) | 0.9789 |
| Healthcare Worker Status | |||||||
| No (Reference group) | 10518 (67%) | 374 (3.6%) | 6.0 (5.4–6.6) | ||||
| Yes | 5290 (33%) | 264 (5%) | 8.1 (7.1–9.1) | 1.14 (0.96–1.35) | 0.1268 | 1.12 (0.92–1.36) | 0.2647 |
| Vaccination Product | |||||||
| Moderna-mRNA-1273 (Reference group) | 3985 (25%) | 120 (3%) | 5.1 (4.2–6.1) | ||||
| Pfizer/BNT-BNT162b2 | 10999 (70%) | 473 (4.3%) | 7.0 (6.4–7.7) | 1.24 (1.02–1.51) | 0.0351 | 1.35 (1.10–1.66) | 0.0042 |
| J&J-Ad26.COV2.S | 824 (5%) | 45 (5.5%) | 10.2 (7.6–13.6) | 2.22 (1.59–3.10) | <0.0001 | 1.74 (1.24–2.44) | 0.0014 |
| Prior COVID Infection | |||||||
| No (Reference group) | 14743 (93%) | 610 (4.1%) | 6.8 (6.3–7.4) | ||||
| Yes | 1065 (7%) | 28 (2.6%) | 4.8 (3.3–6.9) | 0.79 (0.54–1.15) | 0.2129 | 0.58 (0.39–0.85) | 0.0052 |
| County Classification | |||||||
| Urban (Reference group) | 10554 (67%) | 410 (3.9%) | 6.3 (5.7–7.0) | ||||
| Suburban | 2361 (15%) | 111 (4.7%) | 8.1 (6.7–9.7) | 1.32 (1.07–1.62) | 0.0087 | 1.33 (1.08- 1.64) | 0.0076 |
| Rural | 2893 (18%) | 117 (4%) | 7.0 (5.8–8.4) | 1.20 (0.98–1.47) | 0.0756 | 1.24 (1.01–1.53) | 0.0396 |
| Time-varying covariates | |||||||
| Vaccination Rate in County of Residence 3 weeks prior | |||||||
| ≤60% (Reference group) | |||||||
| >60% | 0.81 (0.61–1.07) | 0.1425 | 0.85 (0.64–1.13) | 0.2692 | |||
| Mask Usage in week prior | |||||||
| ≤90% (Reference group) | |||||||
| >90% | 0.61 (0.52–0.73) | <0.0001 | 0.66 (0.56–0.79) | <0.0001 | |||
| Delta Time Frame * | |||||||
| Not in Delta Time Frame (Reference group) | |||||||
| In Delta Time Frame | 0.87 (0.71–1.07) | 0.1814 | 3.54 (2.34–5.35) | <0.0001 | |||
| Omicron Time Frame ** | |||||||
| Not in Omicron Time Frame (Reference group) | |||||||
| In Omicron Time Frame | 4.19 (3.33–5.28) | <0.0001 | 16.68 (10.05–27.68) | <0.0001 | |||
| Receipt of booster shot | |||||||
| No (Reference group) | |||||||
| Yes | 0.35 (0.29–0.43) | <0.0001 | 0.33 (0.27–0.40) | <0.0001 | |||
* Delta Time Frame set as between 28 June 2021 and 21 November 2021. ** Omicron Time Frame set as between 5 December 2021 and 3 January 2022, the end of the observation period for this analysis.