Table 1

Study sample characteristics

Total sampleNo prior
SARS-CoV-2 infection
Prior
SARS-CoV-2 infection
P value*
n84378459
Age in years, median (IQR)41.66 (35.19, 52.80)41.89 (35.25, 53.00)38.72 (34.93, 49.31)0.169
Age in years (range)20.37–87.2620.37–87.2623.52–76.87
Male sex, n (%)256 (30.4)239 (30.5)17 (28.8)0.903
Non-white race, n (%)405 (48.0)372 (47.4)33 (55.9)0.262
Hispanic ethnicity, n (%)86 (10.2)73 (9.3)13 (22.0)0.004
Obesity, n (%)103 (12.2)92 (11.7)11 (18.6)0.175
Hypertension, n (%)128 (15.2)122 (15.6)6 (10.2)0.355
Charlson Comorbidity Index, median (IQR)†0.00 (0.00, 1.00)0.00 (0.00, 1.00)0.00 (0.00, 1.00)0.572
Work environment‡
 ICU, COVID-19 unit135 (16.1)126 (16.2)9 (15.3)1.00
 ICU, non-COVID-19 unit133 (15.9)129 (16.5)4 (6.8)0.073
 Ward, COVID-19 unit160 (19.1)141 (18.1)19 (32.2)0.013
 Ward, non-COVID-19 unit204 (24.3)193 (24.7)11 (18.6)0.37
 Emergency department /urgent care98 (11.7)94 (12.1)4 (6.8)0.315
 Outpatient clinic215 (25.6)206 (26.4)9 (15.3)0.082
 Office129 (15.4)119 (15.3)10 (16.9)0.873
 Work from home61 (7.3)57 (7.3)4 (6.8)1.00
 Other185 (22.1)177 (22.7)8 (13.6)0.142
 Unknown74 (8.8)71 (9.1)3 (5.1)0.423
  • *P value comparing those with versus without prior SARS-CoV-2 infection.

  • †The Charlson Comorbidity Index weights the clinical conditions into a single score to predict 10-year survival: age, myocardial infarction, heart failure, peripheral vascular disease, stroke, dementia, chronic obstructive pulmonary disease, connective tissue disease, peptic ulcer disease, liver disease, diabetes mellitus, hemiplegia, chronic kidney disease, solid tumour, leukaemia, lymphoma and AIDS.

  • ‡Participant-provided work environment. Participants could select multiple environments if they worked in more than one location.

  • ICU, intensive care unit.