Table 1.
Surface samples taken following a SARS-CoV-2 outbreak at a manufacturing workplace, March 2021, in England
|
RT-PCR results (From a total of 66 samples) |
Level of RNA (based on Ct value) |
||||
|---|---|---|---|---|---|
| Confirmed Positive | Suspected Positive | Negative | Moderate-High (Ct <32.0) |
Low (Ct 32.0-34.9) |
Very low-None (Ct ≥35.0a) |
| 8 (12.1%) | 11 (16.7%) | 47 (71.2%) | 0 (0.0%) | 0 (0.0%) | 66 (%) |
| Positive sample information | |||||
| Site area | Location in area | Mean Ct valueb | Estimated copies per cm2c | ||
| Ops Office | Desk and Chair Arms | 37.5 | 699 | ||
| Assembly | Desk and Under Chair | 37.1 | 935 | ||
| Assembly | Stationery Cupboard | 37.7d | 1075 | ||
| Production | Tool Trolley | 36.8 | 2757 | ||
| Maintenance | 2x Clamps + Cupboard | 37.8 | 329 | ||
| Tool Room | Cupboard | 36.7 | 2641 | ||
| Tool Room | Computer | 37.3 | 1524 | ||
| Tool Room | G Clamp Handle | 37.7d | 2206 | ||
| Production | Machinery | 37.6d | 1155 | ||
| WC | Dryer - Board Underneath | 37.3d | 922 | ||
| Canteen 2 | Table and Chairs | 37.3d | 997 | ||
| Canteen 2 | Leather Seat | 37.4d | 1347 | ||
| Maintenance Office | Cupboard - Handles and Inner Door | 37.9d | 882 | ||
| Warehouse | Aircon unit | 36.7 | 918 | ||
| Warehouse | Cleaning station - tool handles | 37.5d | 103 | ||
| Locker room | Locker | 37.3d | 919 | ||
| Locker room | Front of 140, 141 | 37.5d | 790 | ||
| Locker room | Bench | 37.9 | 418 | ||
| Locker room | Bench | 37.4d | 430 | ||
Abbreviations: RT-PCR Reverse transcription-polymerase chain reaction, Ct Cycle threshold, Ops Operations, WC Water Closet
aIncludes 47 samples with no SARS-CoV-2 RNA detected
bMean Ct value for the N gene
cExtrapolation from copies per reaction to copies per sample collected based on the dilution factor, then divided by recorded sampling area
dSample identified as suspected positive, defined as a sample with a single replicate testing positive for at least one target