Table 1:
Characteristics of study population of COVID-19 index cases and close contacts in California prisons.
| Index cases (N=1226) (N (%) or mean (SD)) | Close contacts* (N=1226) (N (%) or mean (SD)) | |||
|---|---|---|---|---|
|
| ||||
| No COVID-19 vaccination (N=273) | Any COVID-19 vaccination (N=953) | No COVID-19 vaccination (N=173) | Any COVID-19 vaccination (N=1053) |
|
|
| ||||
| Sex | ||||
| Female | 8 (3%) | 30 (3%) | 7 (4%) | 31 (3%) |
| Male | 265 (97%) | 923 (97%) | 166 (96%) | 1022 (97%) |
| Age (years) | 36.3 (10) | 39 (10.7) | 35.9 (10.1) | 39.6 (11.1) |
| Race/ethnicity | ||||
| American Indian/Alaskan Native | 0 (0%) | 11 (1%) | 1 (1%) | 10 (1%) |
| Asian or Pacific Islander | 4 (2%) | 12 (1%) | 0 (0%) | 10 (1%) |
| Black | 89 (33%) | 221 (23%) | 56 (32%) | 244 (23%) |
| Hispanic | 145 (53%) | 548 (58%) | 88 (51%) | 599 (57%) |
| White | 28 (10%) | 136 (14%) | 23 (13%) | 155 (15%) |
| Other** | 7 (3%) | 25 (3%) | 5 (3%) | 35 (3%) |
| COVID-19 risk score (range 0–12) *** | 0.7 (1.3) | 1 (1.4) | 0.7 (1) | 1.1 (1.5) |
| Number of days of exposure between index case and close contact | 2.4 (1.2) | 2.2 (1.1) | 2.4 (1.2) | 2.3 (1.1) |
| Prior infection | 84 (31%) | 356 (37%) | 59 (34%) | 448 (43%) |
| Vaccination status | ||||
| Unvaccinated | 273 (100%) | - | 173 (100%) | - |
| Ad26.COV2 | - | 113 (12%) | - | 152 (15%) |
| Completed only primary series | - | 58 (51%) | - | 70 (46%) |
| Received booster or additional doses | - | 55 (49%) | - | 82 (54%) |
| BNT162b2 | - | 188 (20%) | - | 193 (18%) |
| Received 1 dose of primary series | - | 5 (3%) | - | 3 (2%) |
| Completed only primary series | - | 55 (29%) | - | 43 (22%) |
| Received booster or additional doses | - | 128 (68%) | - | 147 (76%) |
| mRNA-1273 | - | 652 (68%) | - | 708 (67%) |
| Received 1 dose of primary series | - | 13 (2%) | - | 25 (4%) |
| Completed only primary series | - | 229 (35%) | - | 223 (31%) |
| Received booster or additional doses | - | 412 (63%) | - | 462 (65%) |
History of prior natural infection and vaccination status reflect the index case and close contact’s vaccination and natural infection status on the day of first positive test (for index cases) or first exposure to an infectious index case (for close contacts)
*
Residents were considered close contacts of two index cases in rare cases (<0.01% of cases)
**
Other race/ethnicity based on self-reported data and those with mixed race/ethnicity
***
COVID-19 risk score was estimated by California Correctional Health Care Services as weighted sum of different comorbidities most associated with severe COVID-19 complications (35)