Table 3.
Predictors of Viral RNA Shedding Among Seronegative Participants
| Coarse Aerosol (>5 μm) | Fine Aerosol (≤5 μm) | |||||
|---|---|---|---|---|---|---|
| Without Face Mask N = 49, n = 78a | Paired ± Mask N = 46,n = 69 | Without Face Mask N = 49, n = 78 | Paired ± Mask N = 46,n = 69 | |||
| Unadjusted | Adjustedb | Estimatec | Unadjusted | Adjusted | Estimate | |
| Alpha variant | 67 (6.7, 660) | 3.6 (0.35, 36) | 100 (16, 650) | 43 (6.6, 280) | 18 (3.4,92) | 73 (15, 350) |
| Face mask | … | … | 0.23 (.11, .49) | … | … | 0.52 (.28, .97) |
| Age | 1.4 (0.44,4.4) | … | … | 1.7 (.74, 3.7) | 1.7 (1, 2.8) | … |
| Day post onsete | 0.79 (0.53, 1.2) | … | … | 0.97 (.76, 1.2) | … | … |
| Log mid-turbinate swab | 480 (40,5700) | 36 (3.5, 370) | … | 13 (4.3, 42) | 7.3 (2.5, 21) | … |
| Log saliva | 4.6 (1.4,15) | 1.5 (.55, 4.3) | … | 2.8 (1.2, 6.5) | 0.96 (.47, 2) | … |
| Number of coughs | 1.2 (0.92,1.5) | 1.2 (1, 1.5) | 1 (0.93, 1.2) | 1.2 (.96, 1.5) | 1.2 (1, 1.3) | 1.1 (1, 1.3) |
| Upper respiratory symptoms | 2.4 (0.91,6.1) | … | … | 1.7 (.83, 3.6) | 0.75 (.44, 1.3) | … |
| Lower respiratory symptoms | 0.99 (0.36,2.7) | 0.4 (0.13,1.2) | … | 0.64 (.3, 1.4) | … | … |
| Gastrointestinal symptoms | 2.3 (1.1,5.2) | 1.2 (.55, 2.4) | … | 1.7 (.94, 3.2) | 1 (.61, 1.7) | … |
| Systemic symptoms | 5.7 (2.5,13) | 2.4 (.97, 6.1) | … | 2.1 (1.1, 4) | 1.1 (.59, 2) | … |
| Alpha variant × face mask | … | … | 0.62 (.15, 2.7) | … | … | 0.7 (.2, 2.4) |
Effect estimates and their 95% confidence intervals are shown as the ratio of RNA copy number of samples: with alpha variant to without alpha variant, with mask to without mask, or as the fold-increase in RNA copy number for a 10-year increase in age, 1-day increase in day post-symptom onset, and an interquartile range change in symptom scores, mid-turbinate swab and saliva RNA copy number. All analyses were controlled for random effects of subject and sample nested within subjects and for censoring by the limit of detection using a linear mixed-effects model for censored responses (R Project lmec package).
aN = Number of participants, n = number of samples for without face mask analysis and number of pairs of same day with and without face masks samples for paired analysis of the effect of face masks.
bAdjusted estimates accounted for potential covariates resulting in >10% change in the estimates of the main exposure variable—“alpha variant.”
cEffect of mask on samples adjusted for alpha variant and number of coughs counted during sample collection.
dFace masks included both surgical masks provided by the investigators and masks currently being used by participants on the day of testing; surgical masks and participant-provided masks were not significantly different (Supplementary Table 5).
e Days since start of symptoms or first positive test if asymptomatic or presymptomatic to breath sample; 2 subjects had no symptoms.