Table 1.
Characteristics of the Study Population
| Antibody Negative | Antibody Positive | All With Serologic Tests | P valuea | |
|---|---|---|---|---|
| Number of participants | 49 | 8 | 57 | … |
| Number of exhaled breath sample visitsb | 78 | 15 | 93 | … |
| Female, N (%) | 18 (37) | 2 (25) | 20 (35) | .70 |
| Age, mean years ± SD | 23.7 ± 9.5 | 24.9 ± 8.4 | 23.8 ± 9.3 | .73 |
| Age group, N (%) | … | |||
| <18 | 1 (2) | 0 (0) | 1 (2) | |
| 18–45 | 45 (92) | 8 (100) | 53 (93) | |
| >45 | 3 (6) | 0 (0) | 3 (5) | |
| White, N (%) | 40 (82) | 5 (62) | 45 (79) | .16 |
| BMI, mean ± SD | 24.6 ± 4.5 | 27.3 ± 4.8 | 25 ± 4.6 | .12 |
| Chronic respiratory illnessc N (%) | 12 (24) | 1 (12) | 13 (23) | .67 |
| Ever smoker N (%) | 2 (4) | 1 (12) | 3 (5) | .37 |
| Has taken singing lessons/part of a choir N (%) | 4 (8) | 0 (0) | 4 (7) | … |
| Alpha variant N (%) | 4 (8) | 0 (0) | 4 (7) | … |
| Days post onsetd mean ± SD (range) | 3.8 ± 2.1 (day 1–10) | 5.9 ± 3.8 (day 0–12) | 4.1 ± 2.5 (day 0–12) | .18 |
| Coughs per 30 min, mean ± SD(range) | 1 ± 3 (0–17) | 3 ± 8 (0–24) | 1 ± 4 (0–24) | .098 |
| Loss of taste/smell N (%) | 13 (27) | 4 (50) | 17 (30) | .22 |
| Median upper respiratory symptoms (IQR)e | 2 (1–3) | 3 (1.5–4) | 2 (1–3) | .17 |
| Median lower respiratory symptoms (IQR) | 0 (0–1.2) | 0 (0–1) | 0 (0–1) | .82 |
| Median systemic symptoms (IQR) | 1 (0–3) | 1 (0–2.5) | 1 (0–3) | .60 |
| Median gastrointestinal symptoms (IQR) | 0 (0–1) | 0 (0) | 0 (0–1) | .36 |
| Temperature, mean Celsius ± SD | 37.2 ± 0.4 | 37.2 ± 0.2 | 37.2 ± 0.3 | .80 |
| Oxygen saturation (SpO2), mean ± SD | 97.9 ± 1 | 97.5 ± 1.1 | 97.8 ± 1 | .25 |
Abbreviations: BMI, body mass index; IQR, interquartile range; SD, standard deviation.
aGroup comparisons were made between antibody negative and positive cases using 2-sample t test for continuous variables and Fisher’s exact test for categorical variables.
bIn total, 57 volunteers provided breath samples and sera at the initial shedding assessment visit; 34 of them provided exhaled breath samples at the 2nd shedding assessment visit approximately 2 days later; 4 volunteers who did not provide sera at the first visit were excluded.
cChronic respiratory illness = volunteers with any chronic obstructive pulmonary disease, asthma, other lung diseases.
dDays since start of symptoms or first positive test if asymptomatic or presymptomatic to first breath sample; 3 subjects reported no symptoms.
eSymptoms at the time of each sample collection visit. Sixteen symptoms were rated from 0 to 3 with a maximum possible composite score of 15 for upper respiratory, 9 for lower respiratory, 12 for systemic symptoms, and 12 for gastrointestinal symptoms.