TABLE 3.
Sampling results for hospital and the local municipal wastewater treatment plant over time
| Source | Sample daya | CT values (N1, N2, RP)b | Determination | Anticipated result based on occupancy or epidemiology | Interpretation | No. of casesc |
|---|---|---|---|---|---|---|
| Hospital | Baselinec | 30.9, 32.5, 30.1 | Positive | Positive | True positive | 30 |
| 8 | 30.6, 33.2, 31.0 | Positive | Positive | True positive | 28 | |
| 9 | 39.1, 37.5, 31.4 | Positive | Positive | True positive | 28 | |
| 9 (duplicate) | 38.4, 38.6, 28.2 | Positive | Positive | True positive | ||
| 12 | 38.3, 38.9, 31.2 | Positive | Positive | True positive | 33 | |
| 35 | 32.2, 33.5, 32.2 | Positive | Positive | True positive | 34 | |
| 35 (duplicate) | 32.7, 34.1, 34.2 | Positive | Positive | True positive | ||
| 50, subsample ae | 34.8, 37.6, 30.4 | Positive | Positive | True positive | 30 | |
| 50, subsample be | 41.9, 41.2, 33.4 | Positive | Positive | True positive | ||
| 51 | 38.9, 41.0, 28.3 | Positive | Positive | True positive | 29 | |
| 52 | 37.7, 40.3, 36.3 | Positive | Positive | True positive | 29 | |
| WWTP, raw influent | Baselined | 30.3, 31.2, 28.3 | Positive | Positive | True positive | 7.9 |
| 8 | 34.0, ND, 30.3 | Indeterminate | Positive | 23.3 | ||
| 21 | 34.2, 35.2, 34.5 | Positive | Positive | True positive | 22.4 | |
| WWTP, primary solids | Baselined | 31.8, 32.5, 34.6 | Positive | Positive | True positive | 7.9 |
| 8 | 30.8, 32.4, 30.9 | Positive | Positive | True positive | 23.3 | |
| 21 | 36.2, 39.2, 35.0 | Positive | Positive | True positive | 22.4 | |
| Tap water | 14 | ND, ND, ND | Negative (no human DNA anticipated) | Negative | True negative | NA |
a
End of overnight sample collection period, which is also the same day samples were processed. Numbering of days was from the start of the study period in early July.
b
ND, not detected (CT ≥ 45).
c
Number of COVID-19 patients in the hospital tower during sample collection (hospital samples); 7-day moving average of new cases for WWTP catchment area (city of Charlottesville) (https://globalepidemics.org/key-metrics-for-covid-suppression/). NA, not applicable.
d
From Table 1.
e
The overnight composite sample was divided. Subsample a was processed the day it was collected. Subsample b was refrigerated and processed 24 h later.