Table 3.
Clinical characteristics of “COVID-19 + Flu” and “Overall COVID-19” cohorts at the Mayo Clinic. The “COVID-19 + Flu” cohort includes all individuals with a positive PCR test for SARS-CoV-2 and at least one of the following within 14 days: a positive laboratory test for influenza, an ICD code for influenza, or a clinical note indicating a diagnosis of influenza. The “Overall COVID-19” cohort includes all individuals with a positive PCR test for SARS-CoV-2. *** implies significant value.
| Clinical characteristic | COVID-19 + Flu cohort case count (%) | Overall COVID-19 cohort case count (%) | Relative risk (95% CI) |
|---|---|---|---|
| Total number of cases | 120 | 197,364 | |
| Type of SARS-CoV-2 infection | |||
| - Primary infection | 111 (92.5%) | 190,916 (96.7%) | 0.96 [0.90, 1.00] |
| - Reinfection | 9 (7.5%) | 6,448 (3.3%) | 2.31 [1.31, 4.45]*** |
| Time of SARS-CoV-2 infection | |||
| - 2020 March 12 to 2021 March 15 | 7 (5.8%) | 77,989 (39.5%) | 0.15 [0.08, 0.31]*** |
| - 2021 March 16 to 2021 June 15 | 1 (0.8%) | 7,685 (3.9%) | 0.21 [0.06, 1.56] |
| - 2021 June 16 to 2021 December 13 | 10 (8.3%) | 49,705 (25.2%) | 0.33 [0.19, 0.61]*** |
| - 2021 December 14 to 2022 April 2 | 102 (85.0%) | 61,952 (31.4%) | 2.71 [2.50, 2.91]*** |
| COVID-19 vaccination status | |||
| - Unvaccinated | 83 (69.2%) | 150,102 (76.0%) | 0.91 [0.81, 1.02] |
| - Partial | 6 (5.0%) | 5,843 (3.0%) | 1.69 [0.86, 3.83] |
| - Full | 31 (25.8%) | 31,624 (16.0%) | 1.61 [1.20, 2.19]*** |
| - Boosted | 0 (0.0%) | 9,795 (5.0%) | 0.00 [0.00, 1.32] |
| Initial COVID-19 vaccine type | |||
| - None | 83 (69.2%) | 150,102 (76.0%) | 0.91 [0.81, 1.02] |
| - Janssen | 3 (2.5%) | 3,065 (1.6%) | 1.61 [0.66, 5.23] |
| - Moderna | 17 (14.2%) | 12,547 (6.4%) | 2.23 [1.47, 3.51]*** |
| - Pfizer/BioNTech | 17 (14.2%) | 31,650 (16.0%) | 0.88 [0.58, 1.39] |
| Flu vaccination status at time of SARS-CoV-2 infection | |||
| - Unvaccinated | 104 (86.7%) | 175,327 (88.9%) | 0.98 [0.91, 1.04] |
| - Vaccinated | 16 (13.3%) | 21,971 (11.1%) | 1.20 [0.78, 1.92] |
| Site | |||
| Mayo Clinic—Arizona | 3 (2.5%) | 18,910 (9.6%) | 0.26 [0.11, 0.85]*** |
| Mayo Clinic—Florida | 5 (4.2%) | 20,686 (10.5%) | 0.40 [0.19, 0.98]*** |
| Mayo Clinic—Midwest | 112 (93.3%) | 157,768 (79.9%) | 1.17 [1.11, 1.22]*** |
| Sex | |||
| - Female | 53 (44.2%) | 101,039 (51.2%) | 0.86 [0.71, 1.06] |
| - Male | 67 (55.8%) | 96,254 (48.8%) | 1.14 [0.98, 1.34] |
| - Unknown/nonbinary | 0 (0.0%) | 71 (0.0%) | 0.00 [0.00, 183.02] |
| Race | |||
| - Asian | 2 (1.7%) | 5,157 (2.6%) | 0.23, 2.70] |
| - Black/African American | 8 (6.7%) | 8,438 (4.3%) | 0.86, 3.15] |
| - Native American | 2 (1.7%) | 912 (0.5%) | 1.31, 15.33]*** |
| - Native Hawaiian/Pacific Islander | 0 (0.0%) | 354 (0.2%) | 0.00, 36.63] |
| - White/Caucasian | 98 (81.7%) | 165,701 (84.0%) | [0.89, 1.06] |
| - Other | 8 (6.7%) | 6,883 (3.5%) | 1.05, 3.85]*** |
| - Unknown | 2 (1.7%) | 9,919 (5.0%) | 0.33 [0.12, 1.40] |
| Ethnicity | |||
| - Hispanic or Latino | 11 (9.2%) | 14,660 (7.4%) | 0.74, 2.22] |
| - Not Hispanic or Latino | 108 (90.0%) | 170,335 (86.3%) | 1.04 [0.98, 1.10] |
| - Unknown | 1 (0.8%) | 12,369 (6.3%) | 0.13 [0.04, 0.97]*** |
| Clinical characteristic | COVID-19 + Flu cohort case count (%) | Overall COVID-19 cohort case count (%) | Mann–Whitney U test P-value |
| Age at time of positive PCR test for SARS-CoV-2 (in years) | |||
| - Mean: | 26.7 | 49.0 | 3.2e-12*** |
| - Median: | 19.9 | 38.7 | |
| - SD: | 20.7 | 21.2 | |
| - IQR: | (11.6, 40.8) | (23.1, 56.4) | |
| Elixhauser Comorbidity Index | |||
| - Mean: | 0.7 | 1.7 | 0.23 |
| - SD: | 5.4 | 6.5 |