Table 1.
Characteristics of participants
| Case participants (Self-reported positive test) | Control participants (Never self-reported positive test) | P-value* | |
|---|---|---|---|
| N | 3,901 | 27,813 | |
| Site of enrollment | <.001 | ||
| Atrium | 1,106 (28.4%) | 6,101 (21.9%) | |
| Campbell | 44 (1.1%) | 553 (2.0%) | |
| New Hanover | 38 (1.0%) | 617 (2.2%) | |
| Vidant | 48 (1.2%) | 1,034 (3.7%) | |
| Wake Forest | 2,356 (60.4%) | 17,089 (61.4%) | |
| Wake Med | 309 (7.9%) | 2,419 (8.7%) | |
| Period of Match | .424 | ||
| Pre-Delta (July2020-June2021) | 1,641 (42.5%) | 12,062 (43.6%) | |
| Delta (July-Nov 2021) | 659 (17.1%) | 4,649 (16.8%) | |
| Omicron (Dec 2021-March 2022) | 1,563 (40.5%) | 10,960 (39.6%) | |
| Age in years | <.001 | ||
| 18-39 y | 1,067 (27.4%) | 8,025 (28.9%) | |
| 40-54 y | 1,463 (37.5%) | 8,072 (29.0%) | |
| 55-64 y | 844 (21.6%) | 5,735 (20.6%) | |
| 65 y† | 527 (13.5%) | 5,981 (21.5%) | |
| Sex | <.001 | ||
| Female | 2,788 (71.5%) | 19,074 (68.6%) | |
| Male | 1,113 (28.5%) | 8,739 (31.4%) | |
| Race and ethnicity | <.001 | ||
| Hispanic | 114 (2.9%) | 661 (2.4%) | |
| NH Black | 169 (4.3%) | 1,505 (5.4%) | |
| NH White | 3,477 (89.1%) | 24,336 (87.5%) | |
| Other | 141 (3.6%) | 1,311 (4.7%) | |
| County classification | <.001 | ||
| Rural | 907 (23.3%) | 5,758 (20.7%) | |
| Suburban | 884 (22.7%) | 5,363 (19.3%) | |
| Urban | 2,110 (54.1%) | 16,692 (60.0%) | |
| Healthcare worker occupation | <.001 | ||
| No | 2,521 (64.6%) | 20,365 (73.2%) | |
| Yes | 1,380 (35.4%) | 7,448 (26.8%) | |
| Vaccination status§ | <.001 | ||
| mRNA ≥14 days after 2nd dose | 2,096 (53.7%) | 15,490 (55.7%) | |
| mRNA ≥1 dose | 158 (4.1%) | 1,358 (4.9%) | |
| Unvaccinated | 1,647 (42.2%) | 10,965 (39.4%) | |
| Education level‡ | <.001 | ||
| College degree | 2,469 (71.7%) | 14,371 (75.3%) | |
| No College degree | 974 (28.3%) | 4,713 (24.7%) | |
| Household size‡ | <.001 | ||
| >2 people | 1,576 (60.0%) | 6,358 (46.2%) | |
| 1-2 people | 1,050 (40.0%) | 7,401 (53.8%) | |
| Any comorbidity§ | .009 | ||
| Yes | 979 (25.8%) | 7,009 (27.9%) | |
| No | 2,811 (74.2%) | 18,132 (72.1%) |
P-values for Pearson's Chi-squared test comparing cases to controls.
Vaccination status at the time of index/match date. We defined vaccination using self-report and categorized participants into 3 categories: ≥14 days after receiving second dose of either the Pfizer BioNTech BNT162b2 or Moderna mRNA-1273 vaccine, receiving at least one dose of either mRNA vaccine or unvaccinated. Participants who reported receiving a non-mRNA vaccine or had an undetermined vaccine status were excluded.
Available on a subset of participants who completed a supplemental survey (N = 3,443 case-participants and N=19,084 control-participants).
Defined as any comorbidity self-reported or in EHR (autoimmune disease, cancer, CVD, diabetes, immunocompromised, liver disease, renal disease, obesity, pulmonary disease, other disease, neurologic disease, substance use disorder, mental health condition). Available on a subset of participants who completed a supplemental survey or had linked EHR data available (N = 3,790 case-participants and N = 25,141 control-participants).