Table 1.
Characteristics of the Indiana University community with testing data from August 2020–May 2021, stratified by single infection and reinfection status
| Demographic characteristics | Total population (N = 83,878)a | Single infection without re-infection (N = 12,198) | Reinfection (N = 74) | p value (reinfection vs single)b | |
|---|---|---|---|---|---|
| First infection | Second infection | ||||
| Age (years), N (%) | 0.1 | ||||
| < 30 | 62,205 (74.2) | 10,731 (88.0) | 70 (94.6) | ||
| 30–40 | 9299 (11.1) | 625 (5.1) | 3 (4.0) | ||
| > 40 | 12,374 (14.7) | 842 (6.9) | 1 (1.4) | ||
| Sex, N (%) | 0.9 | ||||
| Male | 37,607 (44.8) | 5637 (46.2) | 35 (47.3) | ||
| Female | 46,269 (55.2) | 6561 (53.8) | 39 (52.7) | ||
| Unknown | 2 (0.0) | 0 (0) | 0 (0) | ||
| Greek organization membership, N (%) | 0.001 | ||||
| No | 76,905 (91.7) | 9072 (74.4) | 42 (56.8) | ||
| Yes | 6973 (8.3) | 3126 (25.6) | 32 (43.2) | ||
| Greek organization type (among Greek members), N (%) | 0.7 | ||||
| Fraternity | 3147 (45.1) | 1514 (48.4) | 14 (43.7) | ||
| Sorority | 3826 (54.9) | 1612 (51.6) | 18 (56.3) | ||
| IU affiliation status, N (%) | 0.1 | ||||
| Student | 65,831 (78.5) | 11,013 (90.3) | 71 (96.0) | ||
| Staff | 10,685 (12.7) | 875 (7.2) | 1 (1.4) | ||
| Faculty | 7362 (8.8) | 310 (2.5) | 2 (2.7) | ||
| Positive test type, N (%) | 0.1 | ||||
| Asymptomaticc | – | 5584 (45.8) | 41 (55.4) | 41 (55.4) | |
| Symptomaticd | – | 6614 (54.2) | 33 (44.6) | 33 (44.6) | |
| Median date of infection (IQR) | – | 11/11/2020 (9/10/2020, 1/2/2021) | 9/8/2020 (9/1/2020, 11/2/2020) | 2/25/2021 (12/30/2020, 3/29/2021) | < 0.0001 |
| Median time interval (days) between 1st and 2nd infection (IQR) | – | – | – | 123.5 (98.3, 171.8) | – |
aTotal population includes all members of IU affiliated faculty, staff, and students with at least one SARS-CoV-2 test during the study period of August 1, 2020 to May 9, 2021
bp-values for categorical variables are from Chi-square tests. p-values for continuous variables are from Mann–Whitney U tests
cAsymptomatic tests include the following test categories: surveillance, voluntary, and arrival tests. The total number of tests in these categories were 4363, 770, 451, respectively, for single infections; 33, 3, 5, respectively, for the first diagnostic test of reinfected population; and 31, 10, 0, respectively, for the second test of reinfected population
dSymptomatic tests include the following test categories: Self-report, symptomatic, and other tests. The total number of tests in these categories were 4795, 1818, 1, respectively, for single infections; 26, 7, 0, respectively, for the first diagnostic test of reinfected population; and 30, 3, 0, respectively, for the second test of reinfected population